Merge pull request #13049 from MrMino/empty_histrange_means_all

Accept empty history ranges

docs/source/whatsnew/pr/empty-hist-range.rst

@@ -0,0 +1,19 b''
+Empty History Ranges
+====================
+
+A number of magics that take history ranges can now be used with an empty
+range. These magics are:
+
+ * ``%save``
+ * ``%load``
+ * ``%pastebin``
+ * ``%pycat``
+
+Using them this way will make them take the history of the current session up
+to the point of the magic call (such that the magic itself will not be
+included).
+
+Therefore it is now possible to save the whole history to a file using simple
+``%save <filename>``, load and edit it using ``%load`` (makes for a nice usage
+when followed with :kbd:`F2`), send it to dpaste.org using ``%pastebin``, or
+view the whole thing syntax-highlighted with a single ``%pycat``.

IPython/core/history.py

@@ -1,897 +1,907 b''
 """ History related magics and functionality """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 import atexit
 import datetime
 from pathlib import Path
 import re
 import sqlite3
 import threading
 
 from traitlets.config.configurable import LoggingConfigurable
 from decorator import decorator
 from IPython.utils.decorators import undoc
 from IPython.paths import locate_profile
 from traitlets import (
     Any,
     Bool,
     Dict,
     Instance,
     Integer,
     List,
     Unicode,
     Union,
     TraitError,
     default,
     observe,
 )
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 @undoc
 class DummyDB(object):
     """Dummy DB that will act as a black hole for history.
 
     Only used in the absence of sqlite"""
     def execute(*args, **kwargs):
         return []
 
     def commit(self, *args, **kwargs):
         pass
 
     def __enter__(self, *args, **kwargs):
         pass
 
     def __exit__(self, *args, **kwargs):
         pass
 
 
 @decorator
 def only_when_enabled(f, self, *a, **kw):
     """Decorator: return an empty list in the absence of sqlite."""
     if not self.enabled:
         return []
     else:
         return f(self, *a, **kw)
 
 
 # use 16kB as threshold for whether a corrupt history db should be saved
 # that should be at least 100 entries or so
 _SAVE_DB_SIZE = 16384
 
 @decorator
 def catch_corrupt_db(f, self, *a, **kw):
     """A decorator which wraps HistoryAccessor method calls to catch errors from
     a corrupt SQLite database, move the old database out of the way, and create
     a new one.
 
     We avoid clobbering larger databases because this may be triggered due to filesystem issues,
     not just a corrupt file.
     """
     try:
         return f(self, *a, **kw)
     except (sqlite3.DatabaseError, sqlite3.OperationalError) as e:
         self._corrupt_db_counter += 1
         self.log.error("Failed to open SQLite history %s (%s).", self.hist_file, e)
         if self.hist_file != ':memory:':
             if self._corrupt_db_counter > self._corrupt_db_limit:
                 self.hist_file = ':memory:'
                 self.log.error("Failed to load history too many times, history will not be saved.")
             elif self.hist_file.is_file():
                 # move the file out of the way
                 base = str(self.hist_file.parent / self.hist_file.stem)
                 ext = self.hist_file.suffix
                 size = self.hist_file.stat().st_size
                 if size >= _SAVE_DB_SIZE:
                     # if there's significant content, avoid clobbering
                     now = datetime.datetime.now().isoformat().replace(':', '.')
                     newpath = base + '-corrupt-' + now + ext
                     # don't clobber previous corrupt backups
                     for i in range(100):
                         if not Path(newpath).exists():
                             break
                         else:
                             newpath = base + '-corrupt-' + now + (u'-%i' % i) + ext
                 else:
                     # not much content, possibly empty; don't worry about clobbering
                     # maybe we should just delete it?
                     newpath = base + '-corrupt' + ext
                 self.hist_file.rename(newpath)
                 self.log.error("History file was moved to %s and a new file created.", newpath)
             self.init_db()
             return []
         else:
             # Failed with :memory:, something serious is wrong
             raise
 
 
 class HistoryAccessorBase(LoggingConfigurable):
     """An abstract class for History Accessors """
 
     def get_tail(self, n=10, raw=True, output=False, include_latest=False):
         raise NotImplementedError
 
     def search(self, pattern="*", raw=True, search_raw=True,
                output=False, n=None, unique=False):
         raise NotImplementedError
 
     def get_range(self, session, start=1, stop=None, raw=True,output=False):
         raise NotImplementedError
 
     def get_range_by_str(self, rangestr, raw=True, output=False):
         raise NotImplementedError
 
 
 class HistoryAccessor(HistoryAccessorBase):
     """Access the history database without adding to it.
 
     This is intended for use by standalone history tools. IPython shells use
     HistoryManager, below, which is a subclass of this."""
 
     # counter for init_db retries, so we don't keep trying over and over
     _corrupt_db_counter = 0
      # after two failures, fallback on :memory:
     _corrupt_db_limit = 2
 
     # String holding the path to the history file
     hist_file = Union(
         [Instance(Path), Unicode()],
         help="""Path to file to use for SQLite history database.
 
         By default, IPython will put the history database in the IPython
         profile directory.  If you would rather share one history among
         profiles, you can set this value in each, so that they are consistent.
 
         Due to an issue with fcntl, SQLite is known to misbehave on some NFS
         mounts.  If you see IPython hanging, try setting this to something on a
         local disk, e.g::
 
             ipython --HistoryManager.hist_file=/tmp/ipython_hist.sqlite
 
         you can also use the specific value `:memory:` (including the colon
         at both end but not the back ticks), to avoid creating an history file.
 
         """,
     ).tag(config=True)
 
     enabled = Bool(True,
         help="""enable the SQLite history
 
         set enabled=False to disable the SQLite history,
         in which case there will be no stored history, no SQLite connection,
         and no background saving thread.  This may be necessary in some
         threaded environments where IPython is embedded.
         """
     ).tag(config=True)
 
     connection_options = Dict(
         help="""Options for configuring the SQLite connection
 
         These options are passed as keyword args to sqlite3.connect
         when establishing database connections.
         """
     ).tag(config=True)
 
     # The SQLite database
     db = Any()
     @observe('db')
     def _db_changed(self, change):
         """validate the db, since it can be an Instance of two different types"""
         new = change['new']
         connection_types = (DummyDB, sqlite3.Connection)
         if not isinstance(new, connection_types):
             msg = "%s.db must be sqlite3 Connection or DummyDB, not %r" % \
                     (self.__class__.__name__, new)
             raise TraitError(msg)
 
     def __init__(self, profile="default", hist_file="", **traits):
         """Create a new history accessor.
 
         Parameters
         ----------
         profile : str
           The name of the profile from which to open history.
         hist_file : str
           Path to an SQLite history database stored by IPython. If specified,
           hist_file overrides profile.
         config : :class:`~traitlets.config.loader.Config`
           Config object. hist_file can also be set through this.
         """
         # We need a pointer back to the shell for various tasks.
         super(HistoryAccessor, self).__init__(**traits)
         # defer setting hist_file from kwarg until after init,
         # otherwise the default kwarg value would clobber any value
         # set by config
         if hist_file:
             self.hist_file = hist_file
 
         try:
             self.hist_file
         except TraitError:
             # No one has set the hist_file, yet.
             self.hist_file = self._get_hist_file_name(profile)
 
         self.init_db()
 
     def _get_hist_file_name(self, profile='default'):
         """Find the history file for the given profile name.
 
         This is overridden by the HistoryManager subclass, to use the shell's
         active profile.
 
         Parameters
         ----------
         profile : str
           The name of a profile which has a history file.
         """
         return Path(locate_profile(profile)) / "history.sqlite"
 
     @catch_corrupt_db
     def init_db(self):
         """Connect to the database, and create tables if necessary."""
         if not self.enabled:
             self.db = DummyDB()
             return
 
         # use detect_types so that timestamps return datetime objects
         kwargs = dict(detect_types=sqlite3.PARSE_DECLTYPES|sqlite3.PARSE_COLNAMES)
         kwargs.update(self.connection_options)
         self.db = sqlite3.connect(str(self.hist_file), **kwargs)
         self.db.execute("""CREATE TABLE IF NOT EXISTS sessions (session integer
                         primary key autoincrement, start timestamp,
                         end timestamp, num_cmds integer, remark text)""")
         self.db.execute("""CREATE TABLE IF NOT EXISTS history
                 (session integer, line integer, source text, source_raw text,
                 PRIMARY KEY (session, line))""")
         # Output history is optional, but ensure the table's there so it can be
         # enabled later.
         self.db.execute("""CREATE TABLE IF NOT EXISTS output_history
                         (session integer, line integer, output text,
                         PRIMARY KEY (session, line))""")
         self.db.commit()
         # success! reset corrupt db count
         self._corrupt_db_counter = 0
 
     def writeout_cache(self):
         """Overridden by HistoryManager to dump the cache before certain
         database lookups."""
         pass
 
     ## -------------------------------
     ## Methods for retrieving history:
     ## -------------------------------
     def _run_sql(self, sql, params, raw=True, output=False):
         """Prepares and runs an SQL query for the history database.
 
         Parameters
         ----------
         sql : str
           Any filtering expressions to go after SELECT ... FROM ...
         params : tuple
           Parameters passed to the SQL query (to replace "?")
         raw, output : bool
           See :meth:`get_range`
 
         Returns
         -------
         Tuples as :meth:`get_range`
         """
         toget = 'source_raw' if raw else 'source'
         sqlfrom = "history"
         if output:
             sqlfrom = "history LEFT JOIN output_history USING (session, line)"
             toget = "history.%s, output_history.output" % toget
         cur = self.db.execute("SELECT session, line, %s FROM %s " %\
                                 (toget, sqlfrom) + sql, params)
         if output:    # Regroup into 3-tuples, and parse JSON
             return ((ses, lin, (inp, out)) for ses, lin, inp, out in cur)
         return cur
 
     @only_when_enabled
     @catch_corrupt_db
     def get_session_info(self, session):
         """Get info about a session.
 
         Parameters
         ----------
 
         session : int
             Session number to retrieve.
 
         Returns
         -------
 
         session_id : int
            Session ID number
         start : datetime
            Timestamp for the start of the session.
         end : datetime
            Timestamp for the end of the session, or None if IPython crashed.
         num_cmds : int
            Number of commands run, or None if IPython crashed.
         remark : unicode
            A manually set description.
         """
         query = "SELECT * from sessions where session == ?"
         return self.db.execute(query, (session,)).fetchone()
 
     @catch_corrupt_db
     def get_last_session_id(self):
         """Get the last session ID currently in the database.
 
         Within IPython, this should be the same as the value stored in
         :attr:`HistoryManager.session_number`.
         """
         for record in self.get_tail(n=1, include_latest=True):
             return record[0]
 
     @catch_corrupt_db
     def get_tail(self, n=10, raw=True, output=False, include_latest=False):
         """Get the last n lines from the history database.
 
         Parameters
         ----------
         n : int
           The number of lines to get
         raw, output : bool
           See :meth:`get_range`
         include_latest : bool
           If False (default), n+1 lines are fetched, and the latest one
           is discarded. This is intended to be used where the function
           is called by a user command, which it should not return.
 
         Returns
         -------
         Tuples as :meth:`get_range`
         """
         self.writeout_cache()
         if not include_latest:
             n += 1
         cur = self._run_sql("ORDER BY session DESC, line DESC LIMIT ?",
                                 (n,), raw=raw, output=output)
         if not include_latest:
             return reversed(list(cur)[1:])
         return reversed(list(cur))
 
     @catch_corrupt_db
     def search(self, pattern="*", raw=True, search_raw=True,
                output=False, n=None, unique=False):
         """Search the database using unix glob-style matching (wildcards
         * and ?).
 
         Parameters
         ----------
         pattern : str
           The wildcarded pattern to match when searching
         search_raw : bool
           If True, search the raw input, otherwise, the parsed input
         raw, output : bool
           See :meth:`get_range`
         n : None or int
           If an integer is given, it defines the limit of
           returned entries.
         unique : bool
           When it is true, return only unique entries.
 
         Returns
         -------
         Tuples as :meth:`get_range`
         """
         tosearch = "source_raw" if search_raw else "source"
         if output:
             tosearch = "history." + tosearch
         self.writeout_cache()
         sqlform = "WHERE %s GLOB ?" % tosearch
         params = (pattern,)
         if unique:
             sqlform += ' GROUP BY {0}'.format(tosearch)
         if n is not None:
             sqlform += " ORDER BY session DESC, line DESC LIMIT ?"
             params += (n,)
         elif unique:
             sqlform += " ORDER BY session, line"
         cur = self._run_sql(sqlform, params, raw=raw, output=output)
         if n is not None:
             return reversed(list(cur))
         return cur
 
     @catch_corrupt_db
     def get_range(self, session, start=1, stop=None, raw=True,output=False):
         """Retrieve input by session.
 
         Parameters
         ----------
         session : int
             Session number to retrieve.
         start : int
             First line to retrieve.
         stop : int
             End of line range (excluded from output itself). If None, retrieve
             to the end of the session.
         raw : bool
             If True, return untranslated input
         output : bool
             If True, attempt to include output. This will be 'real' Python
             objects for the current session, or text reprs from previous
             sessions if db_log_output was enabled at the time. Where no output
             is found, None is used.
 
         Returns
         -------
         entries
           An iterator over the desired lines. Each line is a 3-tuple, either
           (session, line, input) if output is False, or
           (session, line, (input, output)) if output is True.
         """
         if stop:
             lineclause = "line >= ? AND line < ?"
             params = (session, start, stop)
         else:
             lineclause = "line>=?"
             params = (session, start)
 
         return self._run_sql("WHERE session==? AND %s" % lineclause,
                                     params, raw=raw, output=output)
 
     def get_range_by_str(self, rangestr, raw=True, output=False):
         """Get lines of history from a string of ranges, as used by magic
         commands %hist, %save, %macro, etc.
 
         Parameters
         ----------
         rangestr : str
-          A string specifying ranges, e.g. "5 ~2/1-4". See
-          :func:`magic_history` for full details.
+          A string specifying ranges, e.g. "5 ~2/1-4". If empty string is used,
+          this will return everything from current session's history.
+
+          See the documentation of :func:`%history` for the full details.
+
         raw, output : bool
           As :meth:`get_range`
 
         Returns
         -------
         Tuples as :meth:`get_range`
         """
         for sess, s, e in extract_hist_ranges(rangestr):
             for line in self.get_range(sess, s, e, raw=raw, output=output):
                 yield line
 
 
 class HistoryManager(HistoryAccessor):
     """A class to organize all history-related functionality in one place.
     """
     # Public interface
 
     # An instance of the IPython shell we are attached to
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
                      allow_none=True)
     # Lists to hold processed and raw history. These start with a blank entry
     # so that we can index them starting from 1
     input_hist_parsed = List([""])
     input_hist_raw = List([""])
     # A list of directories visited during session
     dir_hist = List()
     @default('dir_hist')
     def _dir_hist_default(self):
         try:
             return [Path.cwd()]
         except OSError:
             return []
 
     # A dict of output history, keyed with ints from the shell's
     # execution count.
     output_hist = Dict()
     # The text/plain repr of outputs.
     output_hist_reprs = Dict()
 
     # The number of the current session in the history database
     session_number = Integer()
 
     db_log_output = Bool(False,
         help="Should the history database include output? (default: no)"
     ).tag(config=True)
     db_cache_size = Integer(0,
         help="Write to database every x commands (higher values save disk access & power).\n"
         "Values of 1 or less effectively disable caching."
     ).tag(config=True)
     # The input and output caches
     db_input_cache = List()
     db_output_cache = List()
 
     # History saving in separate thread
     save_thread = Instance('IPython.core.history.HistorySavingThread',
                            allow_none=True)
     save_flag = Instance(threading.Event, allow_none=True)
 
     # Private interface
     # Variables used to store the three last inputs from the user.  On each new
     # history update, we populate the user's namespace with these, shifted as
     # necessary.
     _i00 = Unicode(u'')
     _i = Unicode(u'')
     _ii = Unicode(u'')
     _iii = Unicode(u'')
 
     # A regex matching all forms of the exit command, so that we don't store
     # them in the history (it's annoying to rewind the first entry and land on
     # an exit call).
     _exit_re = re.compile(r"(exit|quit)(\s*\(.*\))?$")
 
     def __init__(self, shell=None, config=None, **traits):
         """Create a new history manager associated with a shell instance.
         """
         # We need a pointer back to the shell for various tasks.
         super(HistoryManager, self).__init__(shell=shell, config=config,
             **traits)
         self.save_flag = threading.Event()
         self.db_input_cache_lock = threading.Lock()
         self.db_output_cache_lock = threading.Lock()
 
         try:
             self.new_session()
         except sqlite3.OperationalError:
             self.log.error("Failed to create history session in %s. History will not be saved.",
                 self.hist_file, exc_info=True)
             self.hist_file = ':memory:'
 
         if self.enabled and self.hist_file != ':memory:':
             self.save_thread = HistorySavingThread(self)
             self.save_thread.start()
 
     def _get_hist_file_name(self, profile=None):
         """Get default history file name based on the Shell's profile.
 
         The profile parameter is ignored, but must exist for compatibility with
         the parent class."""
         profile_dir = self.shell.profile_dir.location
         return Path(profile_dir) / "history.sqlite"
 
     @only_when_enabled
     def new_session(self, conn=None):
         """Get a new session number."""
         if conn is None:
             conn = self.db
 
         with conn:
             cur = conn.execute("""INSERT INTO sessions VALUES (NULL, ?, NULL,
                             NULL, "") """, (datetime.datetime.now(),))
             self.session_number = cur.lastrowid
 
     def end_session(self):
         """Close the database session, filling in the end time and line count."""
         self.writeout_cache()
         with self.db:
             self.db.execute("""UPDATE sessions SET end=?, num_cmds=? WHERE
                             session==?""", (datetime.datetime.now(),
                             len(self.input_hist_parsed)-1, self.session_number))
         self.session_number = 0
 
     def name_session(self, name):
         """Give the current session a name in the history database."""
         with self.db:
             self.db.execute("UPDATE sessions SET remark=? WHERE session==?",
                             (name, self.session_number))
 
     def reset(self, new_session=True):
         """Clear the session history, releasing all object references, and
         optionally open a new session."""
         self.output_hist.clear()
         # The directory history can't be completely empty
         self.dir_hist[:] = [Path.cwd()]
 
         if new_session:
             if self.session_number:
                 self.end_session()
             self.input_hist_parsed[:] = [""]
             self.input_hist_raw[:] = [""]
             self.new_session()
 
     # ------------------------------
     # Methods for retrieving history
     # ------------------------------
     def get_session_info(self, session=0):
         """Get info about a session.
 
         Parameters
         ----------
 
         session : int
             Session number to retrieve. The current session is 0, and negative
             numbers count back from current session, so -1 is the previous session.
 
         Returns
         -------
 
         session_id : int
            Session ID number
         start : datetime
            Timestamp for the start of the session.
         end : datetime
            Timestamp for the end of the session, or None if IPython crashed.
         num_cmds : int
            Number of commands run, or None if IPython crashed.
         remark : unicode
            A manually set description.
         """
         if session <= 0:
             session += self.session_number
 
         return super(HistoryManager, self).get_session_info(session=session)
 
     def _get_range_session(self, start=1, stop=None, raw=True, output=False):
         """Get input and output history from the current session. Called by
         get_range, and takes similar parameters."""
         input_hist = self.input_hist_raw if raw else self.input_hist_parsed
 
         n = len(input_hist)
         if start < 0:
             start += n
         if not stop or (stop > n):
             stop = n
         elif stop < 0:
             stop += n
 
         for i in range(start, stop):
             if output:
                 line = (input_hist[i], self.output_hist_reprs.get(i))
             else:
                 line = input_hist[i]
             yield (0, i, line)
 
     def get_range(self, session=0, start=1, stop=None, raw=True,output=False):
         """Retrieve input by session.
 
         Parameters
         ----------
         session : int
             Session number to retrieve. The current session is 0, and negative
             numbers count back from current session, so -1 is previous session.
         start : int
             First line to retrieve.
         stop : int
             End of line range (excluded from output itself). If None, retrieve
             to the end of the session.
         raw : bool
             If True, return untranslated input
         output : bool
             If True, attempt to include output. This will be 'real' Python
             objects for the current session, or text reprs from previous
             sessions if db_log_output was enabled at the time. Where no output
             is found, None is used.
 
         Returns
         -------
         entries
           An iterator over the desired lines. Each line is a 3-tuple, either
           (session, line, input) if output is False, or
           (session, line, (input, output)) if output is True.
         """
         if session <= 0:
             session += self.session_number
         if session==self.session_number:          # Current session
             return self._get_range_session(start, stop, raw, output)
         return super(HistoryManager, self).get_range(session, start, stop, raw,
                                                      output)
 
     ## ----------------------------
     ## Methods for storing history:
     ## ----------------------------
     def store_inputs(self, line_num, source, source_raw=None):
         """Store source and raw input in history and create input cache
         variables ``_i*``.
 
         Parameters
         ----------
         line_num : int
           The prompt number of this input.
 
         source : str
           Python input.
 
         source_raw : str, optional
           If given, this is the raw input without any IPython transformations
           applied to it.  If not given, ``source`` is used.
         """
         if source_raw is None:
             source_raw = source
         source = source.rstrip('\n')
         source_raw = source_raw.rstrip('\n')
 
         # do not store exit/quit commands
         if self._exit_re.match(source_raw.strip()):
             return
 
         self.input_hist_parsed.append(source)
         self.input_hist_raw.append(source_raw)
 
         with self.db_input_cache_lock:
             self.db_input_cache.append((line_num, source, source_raw))
             # Trigger to flush cache and write to DB.
             if len(self.db_input_cache) >= self.db_cache_size:
                 self.save_flag.set()
 
         # update the auto _i variables
         self._iii = self._ii
         self._ii = self._i
         self._i = self._i00
         self._i00 = source_raw
 
         # hackish access to user namespace to create _i1,_i2... dynamically
         new_i = '_i%s' % line_num
         to_main = {'_i': self._i,
                    '_ii': self._ii,
                    '_iii': self._iii,
                    new_i : self._i00 }
 
         if self.shell is not None:
             self.shell.push(to_main, interactive=False)
 
     def store_output(self, line_num):
         """If database output logging is enabled, this saves all the
         outputs from the indicated prompt number to the database. It's
         called by run_cell after code has been executed.
 
         Parameters
         ----------
         line_num : int
           The line number from which to save outputs
         """
         if (not self.db_log_output) or (line_num not in self.output_hist_reprs):
             return
         output = self.output_hist_reprs[line_num]
 
         with self.db_output_cache_lock:
             self.db_output_cache.append((line_num, output))
         if self.db_cache_size <= 1:
             self.save_flag.set()
 
     def _writeout_input_cache(self, conn):
         with conn:
             for line in self.db_input_cache:
                 conn.execute("INSERT INTO history VALUES (?, ?, ?, ?)",
                                 (self.session_number,)+line)
 
     def _writeout_output_cache(self, conn):
         with conn:
             for line in self.db_output_cache:
                 conn.execute("INSERT INTO output_history VALUES (?, ?, ?)",
                                 (self.session_number,)+line)
 
     @only_when_enabled
     def writeout_cache(self, conn=None):
         """Write any entries in the cache to the database."""
         if conn is None:
             conn = self.db
 
         with self.db_input_cache_lock:
             try:
                 self._writeout_input_cache(conn)
             except sqlite3.IntegrityError:
                 self.new_session(conn)
                 print("ERROR! Session/line number was not unique in",
                       "database. History logging moved to new session",
                                                 self.session_number)
                 try:
                     # Try writing to the new session. If this fails, don't
                     # recurse
                     self._writeout_input_cache(conn)
                 except sqlite3.IntegrityError:
                     pass
             finally:
                 self.db_input_cache = []
 
         with self.db_output_cache_lock:
             try:
                 self._writeout_output_cache(conn)
             except sqlite3.IntegrityError:
                 print("!! Session/line number for output was not unique",
                       "in database. Output will not be stored.")
             finally:
                 self.db_output_cache = []
 
 
 class HistorySavingThread(threading.Thread):
     """This thread takes care of writing history to the database, so that
     the UI isn't held up while that happens.
 
     It waits for the HistoryManager's save_flag to be set, then writes out
     the history cache. The main thread is responsible for setting the flag when
     the cache size reaches a defined threshold."""
     daemon = True
     stop_now = False
     enabled = True
     def __init__(self, history_manager):
         super(HistorySavingThread, self).__init__(name="IPythonHistorySavingThread")
         self.history_manager = history_manager
         self.enabled = history_manager.enabled
         atexit.register(self.stop)
 
     @only_when_enabled
     def run(self):
         # We need a separate db connection per thread:
         try:
             self.db = sqlite3.connect(
                 str(self.history_manager.hist_file),
                 **self.history_manager.connection_options
             )
             while True:
                 self.history_manager.save_flag.wait()
                 if self.stop_now:
                     self.db.close()
                     return
                 self.history_manager.save_flag.clear()
                 self.history_manager.writeout_cache(self.db)
         except Exception as e:
             print(("The history saving thread hit an unexpected error (%s)."
                    "History will not be written to the database.") % repr(e))
 
     def stop(self):
         """This can be called from the main thread to safely stop this thread.
 
         Note that it does not attempt to write out remaining history before
         exiting. That should be done by calling the HistoryManager's
         end_session method."""
         self.stop_now = True
         self.history_manager.save_flag.set()
         self.join()
 
 
 # To match, e.g. ~5/8-~2/3
 range_re = re.compile(r"""
 ((?P<startsess>~?\d+)/)?
 (?P<start>\d+)?
 ((?P<sep>[\-:])
  ((?P<endsess>~?\d+)/)?
  (?P<end>\d+))?
 $""", re.VERBOSE)
 
 
 def extract_hist_ranges(ranges_str):
     """Turn a string of history ranges into 3-tuples of (session, start, stop).
 
+    Empty string results in a `[(0, 1, None)]`, i.e. "everything from current
+    session".
+
     Examples
     --------
     >>> list(extract_hist_ranges("~8/5-~7/4 2"))
     [(-8, 5, None), (-7, 1, 5), (0, 2, 3)]
     """
+    if ranges_str == "":
+        yield (0, 1, None)  # Everything from current session
+        return
+
     for range_str in ranges_str.split():
         rmatch = range_re.match(range_str)
         if not rmatch:
             continue
         start = rmatch.group("start")
         if start:
             start = int(start)
             end = rmatch.group("end")
             # If no end specified, get (a, a + 1)
             end = int(end) if end else start + 1
         else:  # start not specified
             if not rmatch.group('startsess'):  # no startsess
                 continue
             start = 1
             end = None  # provide the entire session hist
 
         if rmatch.group("sep") == "-":       # 1-3 == 1:4 --> [1, 2, 3]
             end += 1
         startsess = rmatch.group("startsess") or "0"
         endsess = rmatch.group("endsess") or startsess
         startsess = int(startsess.replace("~","-"))
         endsess = int(endsess.replace("~","-"))
         assert endsess >= startsess, "start session must be earlier than end session"
 
         if endsess == startsess:
             yield (startsess, start, end)
             continue
         # Multiple sessions in one range:
         yield (startsess, start, None)
         for sess in range(startsess+1, endsess):
             yield (sess, 1, None)
         yield (endsess, 1, end)
 
 
 def _format_lineno(session, line):
     """Helper function to format line numbers properly."""
     if session == 0:
         return str(line)
     return "%s#%s" % (session, line)

IPython/core/magics/code.py

@@ -1,750 +1,754 b''
 """Implementation of code management magic functions.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 The IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import inspect
 import io
 import os
 import re
 import sys
 import ast
 from itertools import chain
 from urllib.request import Request, urlopen
 from urllib.parse import urlencode
 from pathlib import Path
 
 # Our own packages
 from IPython.core.error import TryNext, StdinNotImplementedError, UsageError
 from IPython.core.macro import Macro
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.core.oinspect import find_file, find_source_lines
 from IPython.core.release import version
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils.contexts import preserve_keys
 from IPython.utils.path import get_py_filename
 from warnings import warn
 from logging import error
 from IPython.utils.text import get_text_list
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes
 #-----------------------------------------------------------------------------
 
 # Used for exception handling in magic_edit
 class MacroToEdit(ValueError): pass
 
 ipython_input_pat = re.compile(r"<ipython\-input\-(\d+)-[a-z\d]+>$")
 
 # To match, e.g. 8-10 1:5 :10 3-
 range_re = re.compile(r"""
 (?P<start>\d+)?
 ((?P<sep>[\-:])
  (?P<end>\d+)?)?
 $""", re.VERBOSE)
 
 
 def extract_code_ranges(ranges_str):
     """Turn a string of range for %%load into 2-tuples of (start, stop)
     ready to use as a slice of the content split by lines.
 
     Examples
     --------
     list(extract_input_ranges("5-10 2"))
     [(4, 10), (1, 2)]
     """
     for range_str in ranges_str.split():
         rmatch = range_re.match(range_str)
         if not rmatch:
             continue
         sep = rmatch.group("sep")
         start = rmatch.group("start")
         end = rmatch.group("end")
 
         if sep == '-':
             start = int(start) - 1 if start else None
             end = int(end) if end else None
         elif sep == ':':
             start = int(start) - 1 if start else None
             end = int(end) - 1 if end else None
         else:
             end = int(start)
             start = int(start) - 1
         yield (start, end)
 
 
 def extract_symbols(code, symbols):
     """
     Return a tuple  (blocks, not_found)
     where ``blocks`` is a list of code fragments
     for each symbol parsed from code, and ``not_found`` are
     symbols not found in the code.
 
     For example::
 
         In [1]: code = '''a = 10
            ...: def b(): return 42
            ...: class A: pass'''
 
         In [2]: extract_symbols(code, 'A,b,z')
         Out[2]: (['class A: pass\\n', 'def b(): return 42\\n'], ['z'])
     """
     symbols = symbols.split(',')
 
     # this will raise SyntaxError if code isn't valid Python
     py_code = ast.parse(code)
 
     marks = [(getattr(s, 'name', None), s.lineno) for s in py_code.body]
     code = code.split('\n')
 
     symbols_lines = {}
     
     # we already know the start_lineno of each symbol (marks). 
     # To find each end_lineno, we traverse in reverse order until each 
     # non-blank line
     end = len(code)  
     for name, start in reversed(marks):
         while not code[end - 1].strip():
             end -= 1
         if name:
             symbols_lines[name] = (start - 1, end)
         end = start - 1
 
     # Now symbols_lines is a map
     # {'symbol_name': (start_lineno, end_lineno), ...}
     
     # fill a list with chunks of codes for each requested symbol
     blocks = []
     not_found = []
     for symbol in symbols:
         if symbol in symbols_lines:
             start, end = symbols_lines[symbol]
             blocks.append('\n'.join(code[start:end]) + '\n')
         else:
             not_found.append(symbol)
 
     return blocks, not_found
 
 def strip_initial_indent(lines):
     """For %load, strip indent from lines until finding an unindented line.
 
     https://github.com/ipython/ipython/issues/9775
     """
     indent_re = re.compile(r'\s+')
 
     it = iter(lines)
     first_line = next(it)
     indent_match = indent_re.match(first_line)
 
     if indent_match:
         # First line was indented
         indent = indent_match.group()
         yield first_line[len(indent):]
 
         for line in it:
             if line.startswith(indent):
                 yield line[len(indent):]
             else:
                 # Less indented than the first line - stop dedenting
                 yield line
                 break
     else:
         yield first_line
 
     # Pass the remaining lines through without dedenting
     for line in it:
         yield line
 
 
 class InteractivelyDefined(Exception):
     """Exception for interactively defined variable in magic_edit"""
     def __init__(self, index):
         self.index = index
 
 
 @magics_class
 class CodeMagics(Magics):
     """Magics related to code management (loading, saving, editing, ...)."""
 
     def __init__(self, *args, **kwargs):
         self._knowntemps = set()
         super(CodeMagics, self).__init__(*args, **kwargs)
 
     @line_magic
     def save(self, parameter_s=''):
         """Save a set of lines or a macro to a given filename.
 
         Usage:\\
           %save [options] filename n1-n2 n3-n4 ... n5 .. n6 ...
 
         Options:
 
           -r: use 'raw' input.  By default, the 'processed' history is used,
           so that magics are loaded in their transformed version to valid
           Python.  If this option is given, the raw input as typed as the
           command line is used instead.
           
           -f: force overwrite.  If file exists, %save will prompt for overwrite
           unless -f is given.
 
           -a: append to the file instead of overwriting it.
 
         This function uses the same syntax as %history for input ranges,
         then saves the lines to the filename you specify.
 
+        If no ranges are specified, saves history of the current session up to
+        this point.
+
         It adds a '.py' extension to the file if you don't do so yourself, and
         it asks for confirmation before overwriting existing files.
 
         If `-r` option is used, the default extension is `.ipy`.
         """
 
         opts,args = self.parse_options(parameter_s,'fra',mode='list')
         if not args:
             raise UsageError('Missing filename.')
         raw = 'r' in opts
         force = 'f' in opts
         append = 'a' in opts
         mode = 'a' if append else 'w'
         ext = '.ipy' if raw else '.py'
         fname, codefrom = args[0], " ".join(args[1:])
         if not fname.endswith(('.py','.ipy')):
             fname += ext
         file_exists = os.path.isfile(fname)
         if file_exists and not force and not append:
             try:
                 overwrite = self.shell.ask_yes_no('File `%s` exists. Overwrite (y/[N])? ' % fname, default='n')
             except StdinNotImplementedError:
                 print("File `%s` exists. Use `%%save -f %s` to force overwrite" % (fname, parameter_s))
                 return
             if not overwrite :
                 print('Operation cancelled.')
                 return
         try:
             cmds = self.shell.find_user_code(codefrom,raw)
         except (TypeError, ValueError) as e:
             print(e.args[0])
             return
         with io.open(fname, mode, encoding="utf-8") as f:
             if not file_exists or not append:
                 f.write("# coding: utf-8\n")
             f.write(cmds)
             # make sure we end on a newline
             if not cmds.endswith('\n'):
                 f.write('\n')
         print('The following commands were written to file `%s`:' % fname)
         print(cmds)
 
     @line_magic
     def pastebin(self, parameter_s=''):
         """Upload code to dpaste.com, returning the URL.
 
         Usage:\\
           %pastebin [-d "Custom description"][-e 24] 1-7
 
         The argument can be an input history range, a filename, or the name of a
         string or macro.
 
+        If no arguments are given, uploads the history of this session up to
+        this point.
+
         Options:
 
           -d: Pass a custom description. The default will say
               "Pasted from IPython".
           -e: Pass number of days for the link to be expired.
               The default will be 7 days.
         """
         opts, args = self.parse_options(parameter_s, "d:e:")
 
         try:
             code = self.shell.find_user_code(args)
         except (ValueError, TypeError) as e:
             print(e.args[0])
             return
 
         expiry_days = 7
         try:
             expiry_days = int(opts.get("e", 7))
         except ValueError as e:
             print(e.args[0].capitalize())
             return
         if expiry_days < 1 or expiry_days > 365:
             print("Expiry days should be in range of 1 to 365")
             return
 
         post_data = urlencode(
             {
                 "title": opts.get("d", "Pasted from IPython"),
                 "syntax": "python",
                 "content": code,
                 "expiry_days": expiry_days,
             }
         ).encode("utf-8")
 
         request = Request(
             "https://dpaste.com/api/v2/",
             headers={"User-Agent": "IPython v{}".format(version)},
         )
         response = urlopen(request, post_data)
         return response.headers.get('Location')
 
     @line_magic
     def loadpy(self, arg_s):
         """Alias of `%load`
 
         `%loadpy` has gained some flexibility and dropped the requirement of a `.py`
         extension. So it has been renamed simply into %load. You can look at
         `%load`'s docstring for more info.
         """
         self.load(arg_s)
 
     @line_magic
     def load(self, arg_s):
         """Load code into the current frontend.
 
         Usage:\\
           %load [options] source
 
           where source can be a filename, URL, input history range, macro, or
           element in the user namespace
 
+        If no arguments are given, loads the history of this session up to this
+        point.
+
         Options:
 
           -r <lines>: Specify lines or ranges of lines to load from the source.
           Ranges could be specified as x-y (x..y) or in python-style x:y 
           (x..(y-1)). Both limits x and y can be left blank (meaning the 
           beginning and end of the file, respectively).
 
           -s <symbols>: Specify function or classes to load from python source. 
 
           -y : Don't ask confirmation for loading source above 200 000 characters.
 
           -n : Include the user's namespace when searching for source code.
 
         This magic command can either take a local filename, a URL, an history
         range (see %history) or a macro as argument, it will prompt for
         confirmation before loading source with more than 200 000 characters, unless
         -y flag is passed or if the frontend does not support raw_input::
 
+        %load
         %load myscript.py
         %load 7-27
         %load myMacro
         %load http://www.example.com/myscript.py
         %load -r 5-10 myscript.py
         %load -r 10-20,30,40: foo.py
         %load -s MyClass,wonder_function myscript.py
         %load -n MyClass
         %load -n my_module.wonder_function
         """
         opts,args = self.parse_options(arg_s,'yns:r:')
-
-        if not args:
-            raise UsageError('Missing filename, URL, input history range, '
-                             'macro, or element in the user namespace.')
-
         search_ns = 'n' in opts
-
         contents = self.shell.find_user_code(args, search_ns=search_ns)
 
         if 's' in opts:
             try:
                 blocks, not_found = extract_symbols(contents, opts['s'])
             except SyntaxError:
                 # non python code
                 error("Unable to parse the input as valid Python code")
                 return
 
             if len(not_found) == 1:
                 warn('The symbol `%s` was not found' % not_found[0])
             elif len(not_found) > 1:
                 warn('The symbols %s were not found' % get_text_list(not_found,
                                                                      wrap_item_with='`')
                 )
 
             contents = '\n'.join(blocks)
 
         if 'r' in opts:
             ranges = opts['r'].replace(',', ' ')
             lines = contents.split('\n')
             slices = extract_code_ranges(ranges)
             contents = [lines[slice(*slc)] for slc in slices]
             contents = '\n'.join(strip_initial_indent(chain.from_iterable(contents)))
 
         l = len(contents)
 
         # 200 000 is ~ 2500 full 80 character lines
         # so in average, more than 5000 lines
         if l > 200000 and 'y' not in opts:
             try:
                 ans = self.shell.ask_yes_no(("The text you're trying to load seems pretty big"\
                 " (%d characters). Continue (y/[N]) ?" % l), default='n' )
             except StdinNotImplementedError:
                 #assume yes if raw input not implemented
                 ans = True
 
             if ans is False :
                 print('Operation cancelled.')
                 return
 
         contents = "# %load {}\n".format(arg_s) + contents
 
         self.shell.set_next_input(contents, replace=True)
 
     @staticmethod
     def _find_edit_target(shell, args, opts, last_call):
         """Utility method used by magic_edit to find what to edit."""
 
         def make_filename(arg):
             "Make a filename from the given args"
             try:
                 filename = get_py_filename(arg)
             except IOError:
                 # If it ends with .py but doesn't already exist, assume we want
                 # a new file.
                 if arg.endswith('.py'):
                     filename = arg
                 else:
                     filename = None
             return filename
 
         # Set a few locals from the options for convenience:
         opts_prev = 'p' in opts
         opts_raw = 'r' in opts
 
         # custom exceptions
         class DataIsObject(Exception): pass
 
         # Default line number value
         lineno = opts.get('n',None)
 
         if opts_prev:
             args = '_%s' % last_call[0]
             if args not in shell.user_ns:
                 args = last_call[1]
 
         # by default this is done with temp files, except when the given
         # arg is a filename
         use_temp = True
 
         data = ''
 
         # First, see if the arguments should be a filename.
         filename = make_filename(args)
         if filename:
             use_temp = False
         elif args:
             # Mode where user specifies ranges of lines, like in %macro.
             data = shell.extract_input_lines(args, opts_raw)
             if not data:
                 try:
                     # Load the parameter given as a variable. If not a string,
                     # process it as an object instead (below)
 
                     #print '*** args',args,'type',type(args)  # dbg
                     data = eval(args, shell.user_ns)
                     if not isinstance(data, str):
                         raise DataIsObject
 
                 except (NameError,SyntaxError):
                     # given argument is not a variable, try as a filename
                     filename = make_filename(args)
                     if filename is None:
                         warn("Argument given (%s) can't be found as a variable "
                              "or as a filename." % args)
                         return (None, None, None)
                     use_temp = False
 
                 except DataIsObject as e:
                     # macros have a special edit function
                     if isinstance(data, Macro):
                         raise MacroToEdit(data) from e
 
                     # For objects, try to edit the file where they are defined
                     filename = find_file(data)
                     if filename:
                         if 'fakemodule' in filename.lower() and \
                             inspect.isclass(data):
                             # class created by %edit? Try to find source
                             # by looking for method definitions instead, the
                             # __module__ in those classes is FakeModule.
                             attrs = [getattr(data, aname) for aname in dir(data)]
                             for attr in attrs:
                                 if not inspect.ismethod(attr):
                                     continue
                                 filename = find_file(attr)
                                 if filename and \
                                   'fakemodule' not in filename.lower():
                                     # change the attribute to be the edit
                                     # target instead
                                     data = attr
                                     break
                         
                         m = ipython_input_pat.match(os.path.basename(filename))
                         if m:
                             raise InteractivelyDefined(int(m.groups()[0])) from e
 
                         datafile = 1
                     if filename is None:
                         filename = make_filename(args)
                         datafile = 1
                         if filename is not None:
                             # only warn about this if we get a real name
                             warn('Could not find file where `%s` is defined.\n'
                              'Opening a file named `%s`' % (args, filename))
                     # Now, make sure we can actually read the source (if it was
                     # in a temp file it's gone by now).
                     if datafile:
                         if lineno is None:
                             lineno = find_source_lines(data)
                         if lineno is None:
                             filename = make_filename(args)
                             if filename is None:
                                 warn('The file where `%s` was defined '
                                      'cannot be read or found.' % data)
                                 return (None, None, None)
                     use_temp = False
 
         if use_temp:
             filename = shell.mktempfile(data)
             print('IPython will make a temporary file named:',filename)
 
         # use last_call to remember the state of the previous call, but don't
         # let it be clobbered by successive '-p' calls.
         try:
             last_call[0] = shell.displayhook.prompt_count
             if not opts_prev:
                 last_call[1] = args
         except:
             pass
 
 
         return filename, lineno, use_temp
 
     def _edit_macro(self,mname,macro):
         """open an editor with the macro data in a file"""
         filename = self.shell.mktempfile(macro.value)
         self.shell.hooks.editor(filename)
 
         # and make a new macro object, to replace the old one
         mvalue = Path(filename).read_text()
         self.shell.user_ns[mname] = Macro(mvalue)
 
     @skip_doctest
     @line_magic
     def edit(self, parameter_s='',last_call=['','']):
         """Bring up an editor and execute the resulting code.
 
         Usage:
           %edit [options] [args]
 
         %edit runs IPython's editor hook. The default version of this hook is
         set to call the editor specified by your $EDITOR environment variable.
         If this isn't found, it will default to vi under Linux/Unix and to
         notepad under Windows. See the end of this docstring for how to change
         the editor hook.
 
         You can also set the value of this editor via the
         ``TerminalInteractiveShell.editor`` option in your configuration file.
         This is useful if you wish to use a different editor from your typical
         default with IPython (and for Windows users who typically don't set
         environment variables).
 
         This command allows you to conveniently edit multi-line code right in
         your IPython session.
 
         If called without arguments, %edit opens up an empty editor with a
         temporary file and will execute the contents of this file when you
         close it (don't forget to save it!).
 
 
         Options:
 
         -n <number>: open the editor at a specified line number.  By default,
         the IPython editor hook uses the unix syntax 'editor +N filename', but
         you can configure this by providing your own modified hook if your
         favorite editor supports line-number specifications with a different
         syntax.
 
         -p: this will call the editor with the same data as the previous time
         it was used, regardless of how long ago (in your current session) it
         was.
 
         -r: use 'raw' input.  This option only applies to input taken from the
         user's history.  By default, the 'processed' history is used, so that
         magics are loaded in their transformed version to valid Python.  If
         this option is given, the raw input as typed as the command line is
         used instead.  When you exit the editor, it will be executed by
         IPython's own processor.
 
         -x: do not execute the edited code immediately upon exit. This is
         mainly useful if you are editing programs which need to be called with
         command line arguments, which you can then do using %run.
 
 
         Arguments:
 
         If arguments are given, the following possibilities exist:
 
         - If the argument is a filename, IPython will load that into the
           editor. It will execute its contents with execfile() when you exit,
           loading any code in the file into your interactive namespace.
 
         - The arguments are ranges of input history,  e.g. "7 ~1/4-6".
           The syntax is the same as in the %history magic.
 
         - If the argument is a string variable, its contents are loaded
           into the editor. You can thus edit any string which contains
           python code (including the result of previous edits).
 
         - If the argument is the name of an object (other than a string),
           IPython will try to locate the file where it was defined and open the
           editor at the point where it is defined. You can use `%edit function`
           to load an editor exactly at the point where 'function' is defined,
           edit it and have the file be executed automatically.
 
         - If the object is a macro (see %macro for details), this opens up your
           specified editor with a temporary file containing the macro's data.
           Upon exit, the macro is reloaded with the contents of the file.
 
         Note: opening at an exact line is only supported under Unix, and some
         editors (like kedit and gedit up to Gnome 2.8) do not understand the
         '+NUMBER' parameter necessary for this feature. Good editors like
         (X)Emacs, vi, jed, pico and joe all do.
 
         After executing your code, %edit will return as output the code you
         typed in the editor (except when it was an existing file). This way
         you can reload the code in further invocations of %edit as a variable,
         via _<NUMBER> or Out[<NUMBER>], where <NUMBER> is the prompt number of
         the output.
 
         Note that %edit is also available through the alias %ed.
 
         This is an example of creating a simple function inside the editor and
         then modifying it. First, start up the editor::
 
           In [1]: edit
           Editing... done. Executing edited code...
           Out[1]: 'def foo():\\n    print "foo() was defined in an editing
           session"\\n'
 
         We can then call the function foo()::
 
           In [2]: foo()
           foo() was defined in an editing session
 
         Now we edit foo.  IPython automatically loads the editor with the
         (temporary) file where foo() was previously defined::
 
           In [3]: edit foo
           Editing... done. Executing edited code...
 
         And if we call foo() again we get the modified version::
 
           In [4]: foo()
           foo() has now been changed!
 
         Here is an example of how to edit a code snippet successive
         times. First we call the editor::
 
           In [5]: edit
           Editing... done. Executing edited code...
           hello
           Out[5]: "print 'hello'\\n"
 
         Now we call it again with the previous output (stored in _)::
 
           In [6]: edit _
           Editing... done. Executing edited code...
           hello world
           Out[6]: "print 'hello world'\\n"
 
         Now we call it with the output #8 (stored in _8, also as Out[8])::
 
           In [7]: edit _8
           Editing... done. Executing edited code...
           hello again
           Out[7]: "print 'hello again'\\n"
 
 
         Changing the default editor hook:
 
         If you wish to write your own editor hook, you can put it in a
         configuration file which you load at startup time.  The default hook
         is defined in the IPython.core.hooks module, and you can use that as a
         starting example for further modifications.  That file also has
         general instructions on how to set a new hook for use once you've
         defined it."""
         opts,args = self.parse_options(parameter_s,'prxn:')
 
         try:
             filename, lineno, is_temp = self._find_edit_target(self.shell, 
                                                        args, opts, last_call)
         except MacroToEdit as e:
             self._edit_macro(args, e.args[0])
             return
         except InteractivelyDefined as e:
             print("Editing In[%i]" % e.index)
             args = str(e.index)
             filename, lineno, is_temp = self._find_edit_target(self.shell, 
                                                        args, opts, last_call)
         if filename is None:
             # nothing was found, warnings have already been issued,
             # just give up.
             return
 
         if is_temp:
             self._knowntemps.add(filename)
         elif (filename in self._knowntemps):
             is_temp = True
 
 
         # do actual editing here
         print('Editing...', end=' ')
         sys.stdout.flush()
         filepath = Path(filename)
         try:
             # Quote filenames that may have spaces in them when opening
             # the editor
             quoted = filename = str(filepath.absolute())
             if " " in quoted:
                 quoted = "'%s'" % quoted
             self.shell.hooks.editor(quoted, lineno)
         except TryNext:
             warn('Could not open editor')
             return
 
         # XXX TODO: should this be generalized for all string vars?
         # For now, this is special-cased to blocks created by cpaste
         if args.strip() == "pasted_block":
             self.shell.user_ns["pasted_block"] = filepath.read_text()
 
         if 'x' in opts:  # -x prevents actual execution
             print()
         else:
             print('done. Executing edited code...')
             with preserve_keys(self.shell.user_ns, '__file__'):
                 if not is_temp:
                     self.shell.user_ns['__file__'] = filename
                 if 'r' in opts:    # Untranslated IPython code
                     source = filepath.read_text()
                     self.shell.run_cell(source, store_history=False)
                 else:
                     self.shell.safe_execfile(filename, self.shell.user_ns,
                                              self.shell.user_ns)
 
         if is_temp:
             try:
                 return filepath.read_text()
             except IOError as msg:
                 if Path(msg.filename) == filepath:
                     warn('File not found. Did you forget to save?')
                     return
                 else:
                     self.shell.showtraceback()

IPython/core/magics/history.py

@@ -1,335 +1,333 b''
 """Implementation of magic functions related to History.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012, IPython Development Team.
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import os
 import sys
 from io import open as io_open
 import fnmatch
 
 # Our own packages
 from IPython.core.error import StdinNotImplementedError
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.core.magic_arguments import (argument, magic_arguments,
                                           parse_argstring)
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import io
 
 #-----------------------------------------------------------------------------
 # Magics class implementation
 #-----------------------------------------------------------------------------
 
 
 _unspecified = object()
 
 
 @magics_class
 class HistoryMagics(Magics):
 
     @magic_arguments()
     @argument(
         '-n', dest='print_nums', action='store_true', default=False,
         help="""
         print line numbers for each input.
         This feature is only available if numbered prompts are in use.
         """)
     @argument(
         '-o', dest='get_output', action='store_true', default=False,
         help="also print outputs for each input.")
     @argument(
         '-p', dest='pyprompts', action='store_true', default=False,
         help="""
         print classic '>>>' python prompts before each input.
         This is useful for making documentation, and in conjunction
         with -o, for producing doctest-ready output.
         """)
     @argument(
         '-t', dest='raw', action='store_false', default=True,
         help="""
         print the 'translated' history, as IPython understands it.
         IPython filters your input and converts it all into valid Python
         source before executing it (things like magics or aliases are turned
         into function calls, for example). With this option, you'll see the
         native history instead of the user-entered version: '%%cd /' will be
         seen as 'get_ipython().run_line_magic("cd", "/")' instead of '%%cd /'.
         """)
     @argument(
         '-f', dest='filename',
         help="""
         FILENAME: instead of printing the output to the screen, redirect
         it to the given file.  The file is always overwritten, though *when
         it can*, IPython asks for confirmation first. In particular, running
         the command 'history -f FILENAME' from the IPython Notebook
         interface will replace FILENAME even if it already exists *without*
         confirmation.
         """)
     @argument(
         '-g', dest='pattern', nargs='*', default=None,
         help="""
         treat the arg as a glob pattern to search for in (full) history.
         This includes the saved history (almost all commands ever written).
         The pattern may contain '?' to match one unknown character and '*'
         to match any number of unknown characters. Use '%%hist -g' to show
         full saved history (may be very long).
         """)
     @argument(
         '-l', dest='limit', type=int, nargs='?', default=_unspecified,
         help="""
         get the last n lines from all sessions. Specify n as a single
         arg, or the default is the last 10 lines.
         """)
     @argument(
         '-u', dest='unique', action='store_true',
         help="""
         when searching history using `-g`, show only unique history.
         """)
     @argument('range', nargs='*')
     @skip_doctest
     @line_magic
     def history(self, parameter_s = ''):
         """Print input history (_i<n> variables), with most recent last.
 
         By default, input history is printed without line numbers so it can be
         directly pasted into an editor. Use -n to show them.
 
         By default, all input history from the current session is displayed.
         Ranges of history can be indicated using the syntax:
         
         ``4``
             Line 4, current session
         ``4-6``
             Lines 4-6, current session
         ``243/1-5``
             Lines 1-5, session 243
         ``~2/7``
             Line 7, session 2 before current
         ``~8/1-~6/5``
             From the first line of 8 sessions ago, to the fifth line of 6
             sessions ago.
         
         Multiple ranges can be entered, separated by spaces
 
         The same syntax is used by %macro, %save, %edit, %rerun
 
         Examples
         --------
         ::
 
           In [6]: %history -n 4-6
           4:a = 12
           5:print a**2
           6:%history -n 4-6
 
         """
 
         args = parse_argstring(self.history, parameter_s)
 
         # For brevity
         history_manager = self.shell.history_manager
 
         def _format_lineno(session, line):
             """Helper function to format line numbers properly."""
             if session in (0, history_manager.session_number):
                 return str(line)
             return "%s/%s" % (session, line)
 
         # Check if output to specific file was requested.
         outfname = args.filename
         if not outfname:
             outfile = sys.stdout  # default
             # We don't want to close stdout at the end!
             close_at_end = False
         else:
             if os.path.exists(outfname):
                 try:
                     ans = io.ask_yes_no("File %r exists. Overwrite?" % outfname)
                 except StdinNotImplementedError:
                     ans = True
                 if not ans:
                     print('Aborting.')
                     return
                 print("Overwriting file.")
             outfile = io_open(outfname, 'w', encoding='utf-8')
             close_at_end = True
 
         print_nums = args.print_nums
         get_output = args.get_output
         pyprompts = args.pyprompts
         raw = args.raw
 
         pattern = None
         limit = None if args.limit is _unspecified else args.limit
 
         range_pattern = False
         if args.pattern is not None and not args.range:
             if args.pattern:
                 pattern = "*" + " ".join(args.pattern) + "*"
             else:
                 pattern = "*"
             hist = history_manager.search(pattern, raw=raw, output=get_output,
                                           n=limit, unique=args.unique)
             print_nums = True
         elif args.limit is not _unspecified:
             n = 10 if limit is None else limit
             hist = history_manager.get_tail(n, raw=raw, output=get_output)
         else:
-            if args.range:      # Get history by ranges
-                if args.pattern:
-                    range_pattern = "*" + " ".join(args.pattern) + "*"
-                    print_nums = True
-                hist = history_manager.get_range_by_str(" ".join(args.range),
-                                                        raw, get_output)
-            else:               # Just get history for the current session
-                hist = history_manager.get_range(raw=raw, output=get_output)
+            if args.pattern:
+                range_pattern = "*" + " ".join(args.pattern) + "*"
+                print_nums = True
+            hist = history_manager.get_range_by_str(
+                " ".join(args.range), raw, get_output
+            )
 
         # We could be displaying the entire history, so let's not try to pull
         # it into a list in memory. Anything that needs more space will just
         # misalign.
         width = 4
 
         for session, lineno, inline in hist:
             # Print user history with tabs expanded to 4 spaces.  The GUI
             # clients use hard tabs for easier usability in auto-indented code,
             # but we want to produce PEP-8 compliant history for safe pasting
             # into an editor.
             if get_output:
                 inline, output = inline
             if range_pattern:
                 if not fnmatch.fnmatch(inline, range_pattern):
                     continue
             inline = inline.expandtabs(4).rstrip()
 
             multiline = "\n" in inline
             line_sep = '\n' if multiline else ' '
             if print_nums:
                 print(u'%s:%s' % (_format_lineno(session, lineno).rjust(width),
                         line_sep),  file=outfile, end=u'')
             if pyprompts:
                 print(u">>> ", end=u"", file=outfile)
                 if multiline:
                     inline = "\n... ".join(inline.splitlines()) + "\n..."
             print(inline, file=outfile)
             if get_output and output:
                 print(output, file=outfile)
 
         if close_at_end:
             outfile.close()
 
     @line_magic
     def recall(self, arg):
         r"""Repeat a command, or get command to input line for editing.
 
         %recall and %rep are equivalent.
 
         - %recall (no arguments):
 
         Place a string version of last computation result (stored in the
         special '_' variable) to the next input prompt. Allows you to create
         elaborate command lines without using copy-paste::
 
              In[1]: l = ["hei", "vaan"]
              In[2]: "".join(l)
             Out[2]: heivaan
              In[3]: %recall
              In[4]: heivaan_ <== cursor blinking
 
         %recall 45
 
         Place history line 45 on the next input prompt. Use %hist to find
         out the number.
 
         %recall 1-4
 
         Combine the specified lines into one cell, and place it on the next
         input prompt. See %history for the slice syntax.
 
         %recall foo+bar
 
         If foo+bar can be evaluated in the user namespace, the result is
         placed at the next input prompt. Otherwise, the history is searched
         for lines which contain that substring, and the most recent one is
         placed at the next input prompt.
         """
         if not arg:                 # Last output
             self.shell.set_next_input(str(self.shell.user_ns["_"]))
             return
                                     # Get history range
         histlines = self.shell.history_manager.get_range_by_str(arg)
         cmd = "\n".join(x[2] for x in histlines)
         if cmd:
             self.shell.set_next_input(cmd.rstrip())
             return
 
         try:                        # Variable in user namespace
             cmd = str(eval(arg, self.shell.user_ns))
         except Exception:           # Search for term in history
             histlines = self.shell.history_manager.search("*"+arg+"*")
             for h in reversed([x[2] for x in histlines]):
                 if 'recall' in h or 'rep' in h:
                     continue
                 self.shell.set_next_input(h.rstrip())
                 return
         else:
             self.shell.set_next_input(cmd.rstrip())
             return
         print("Couldn't evaluate or find in history:", arg)
 
     @line_magic
     def rerun(self, parameter_s=''):
         """Re-run previous input
 
         By default, you can specify ranges of input history to be repeated
         (as with %history). With no arguments, it will repeat the last line.
 
         Options:
 
           -l <n> : Repeat the last n lines of input, not including the
           current command.
 
           -g foo : Repeat the most recent line which contains foo
         """
         opts, args = self.parse_options(parameter_s, 'l:g:', mode='string')
         if "l" in opts:         # Last n lines
             n = int(opts['l'])
 
             if n == 0:
                 print("Requested 0 last lines - nothing to run")
                 return
             elif n < 0:
                 print("Number of lines to rerun cannot be negative")
                 return
 
             hist = self.shell.history_manager.get_tail(n)
         elif "g" in opts:       # Search
             p = "*"+opts['g']+"*"
             hist = list(self.shell.history_manager.search(p))
             for l in reversed(hist):
                 if "rerun" not in l[2]:
                     hist = [l]     # The last match which isn't a %rerun
                     break
             else:
                 hist = []          # No matches except %rerun
         elif args:              # Specify history ranges
             hist = self.shell.history_manager.get_range_by_str(args)
         else:                   # Last line
             hist = self.shell.history_manager.get_tail(1)
         hist = [x[2] for x in hist]
         if not hist:
             print("No lines in history match specification")
             return
         histlines = "\n".join(hist)
         print("=== Executing: ===")
         print(histlines)
         print("=== Output: ===")
         self.shell.run_cell("\n".join(hist), store_history=False)

IPython/core/magics/osm.py

@@ -1,860 +1,859 b''
 """Implementation of magic functions for interaction with the OS.
 
 Note: this module is named 'osm' instead of 'os' to avoid a collision with the
 builtin.
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import io
 import os
 import re
 import sys
 from pprint import pformat
 
 from IPython.core import magic_arguments
 from IPython.core import oinspect
 from IPython.core import page
 from IPython.core.alias import AliasError, Alias
 from IPython.core.error import UsageError
 from IPython.core.magic import  (
     Magics, compress_dhist, magics_class, line_magic, cell_magic, line_cell_magic
 )
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils.openpy import source_to_unicode
 from IPython.utils.process import abbrev_cwd
 from IPython.utils.terminal import set_term_title
 from traitlets import Bool
 from warnings import warn
 
 
 @magics_class
 class OSMagics(Magics):
     """Magics to interact with the underlying OS (shell-type functionality).
     """
 
     cd_force_quiet = Bool(False,
         help="Force %cd magic to be quiet even if -q is not passed."
     ).tag(config=True)
 
     def __init__(self, shell=None, **kwargs):
 
         # Now define isexec in a cross platform manner.
         self.is_posix = False
         self.execre = None
         if os.name == 'posix':
             self.is_posix = True
         else:
             try:
                 winext = os.environ['pathext'].replace(';','|').replace('.','')
             except KeyError:
                 winext = 'exe|com|bat|py'
             try:
                 self.execre = re.compile(r'(.*)\.(%s)$' % winext,re.IGNORECASE)
             except re.error:
                 warn("Seems like your pathext environmental "
                      "variable is malformed. Please check it to "
                      "enable a proper handle of file extensions "
                      "managed for your system")
                 winext = 'exe|com|bat|py'
                 self.execre = re.compile(r'(.*)\.(%s)$' % winext,re.IGNORECASE)
 
         # call up the chain
         super().__init__(shell=shell, **kwargs)
 
 
     @skip_doctest
     def _isexec_POSIX(self, file):
         """
             Test for executable on a POSIX system
         """
         if os.access(file.path, os.X_OK):
             # will fail on maxOS if access is not X_OK
             return file.is_file()
         return False
 
 
     
     @skip_doctest
     def _isexec_WIN(self, file):
         """
             Test for executable file on non POSIX system
         """
         return file.is_file() and self.execre.match(file.name) is not None
 
     @skip_doctest
     def isexec(self, file):
         """
             Test for executable file on non POSIX system
         """
         if self.is_posix:
             return self._isexec_POSIX(file)
         else:
             return self._isexec_WIN(file)
 
 
     @skip_doctest
     @line_magic
     def alias(self, parameter_s=''):
         """Define an alias for a system command.
 
         '%alias alias_name cmd' defines 'alias_name' as an alias for 'cmd'
 
         Then, typing 'alias_name params' will execute the system command 'cmd
         params' (from your underlying operating system).
 
         Aliases have lower precedence than magic functions and Python normal
         variables, so if 'foo' is both a Python variable and an alias, the
         alias can not be executed until 'del foo' removes the Python variable.
 
         You can use the %l specifier in an alias definition to represent the
         whole line when the alias is called.  For example::
 
           In [2]: alias bracket echo "Input in brackets: <%l>"
           In [3]: bracket hello world
           Input in brackets: <hello world>
 
         You can also define aliases with parameters using %s specifiers (one
         per parameter)::
 
           In [1]: alias parts echo first %s second %s
           In [2]: %parts A B
           first A second B
           In [3]: %parts A
           Incorrect number of arguments: 2 expected.
           parts is an alias to: 'echo first %s second %s'
 
         Note that %l and %s are mutually exclusive.  You can only use one or
         the other in your aliases.
 
         Aliases expand Python variables just like system calls using ! or !!
         do: all expressions prefixed with '$' get expanded.  For details of
         the semantic rules, see PEP-215:
         http://www.python.org/peps/pep-0215.html.  This is the library used by
         IPython for variable expansion.  If you want to access a true shell
         variable, an extra $ is necessary to prevent its expansion by
         IPython::
 
           In [6]: alias show echo
           In [7]: PATH='A Python string'
           In [8]: show $PATH
           A Python string
           In [9]: show $$PATH
           /usr/local/lf9560/bin:/usr/local/intel/compiler70/ia32/bin:...
 
         You can use the alias facility to access all of $PATH.  See the %rehashx
         function, which automatically creates aliases for the contents of your
         $PATH.
 
         If called with no parameters, %alias prints the current alias table
         for your system.  For posix systems, the default aliases are 'cat',
         'cp', 'mv', 'rm', 'rmdir', and 'mkdir', and other platform-specific
         aliases are added.  For windows-based systems, the default aliases are
         'copy', 'ddir', 'echo', 'ls', 'ldir', 'mkdir', 'ren', and 'rmdir'.
 
         You can see the definition of alias by adding a question mark in the
         end::
 
           In [1]: cat?
           Repr: <alias cat for 'cat'>"""
 
         par = parameter_s.strip()
         if not par:
             aliases = sorted(self.shell.alias_manager.aliases)
             # stored = self.shell.db.get('stored_aliases', {} )
             # for k, v in stored:
             #     atab.append(k, v[0])
 
             print("Total number of aliases:", len(aliases))
             sys.stdout.flush()
             return aliases
 
         # Now try to define a new one
         try:
             alias,cmd = par.split(None, 1)
         except TypeError:
             print(oinspect.getdoc(self.alias))
             return
         
         try:
             self.shell.alias_manager.define_alias(alias, cmd)
         except AliasError as e:
             print(e)
     # end magic_alias
 
     @line_magic
     def unalias(self, parameter_s=''):
         """Remove an alias"""
 
         aname = parameter_s.strip()
         try:
             self.shell.alias_manager.undefine_alias(aname)
         except ValueError as e:
             print(e)
             return
         
         stored = self.shell.db.get('stored_aliases', {} )
         if aname in stored:
             print("Removing %stored alias",aname)
             del stored[aname]
             self.shell.db['stored_aliases'] = stored
 
     @line_magic
     def rehashx(self, parameter_s=''):
         """Update the alias table with all executable files in $PATH.
 
         rehashx explicitly checks that every entry in $PATH is a file
         with execute access (os.X_OK).
 
         Under Windows, it checks executability as a match against a
         '|'-separated string of extensions, stored in the IPython config
         variable win_exec_ext.  This defaults to 'exe|com|bat'.
 
         This function also resets the root module cache of module completer,
         used on slow filesystems.
         """
         from IPython.core.alias import InvalidAliasError
 
         # for the benefit of module completer in ipy_completers.py
         del self.shell.db['rootmodules_cache']
 
         path = [os.path.abspath(os.path.expanduser(p)) for p in
             os.environ.get('PATH','').split(os.pathsep)]
 
         syscmdlist = []
         savedir = os.getcwd()
 
         # Now walk the paths looking for executables to alias.
         try:
             # write the whole loop for posix/Windows so we don't have an if in
             # the innermost part
             if self.is_posix:
                 for pdir in path:
                     try:
                         os.chdir(pdir)
                     except OSError:
                         continue
 
                     # for python 3.6+ rewrite to: with os.scandir(pdir) as dirlist:
                     dirlist = os.scandir(path=pdir)
                     for ff in dirlist:
                         if self.isexec(ff):
                             fname = ff.name
                             try:
                                 # Removes dots from the name since ipython
                                 # will assume names with dots to be python.
                                 if not self.shell.alias_manager.is_alias(fname):
                                     self.shell.alias_manager.define_alias(
                                         fname.replace('.',''), fname)
                             except InvalidAliasError:
                                 pass
                             else:
                                 syscmdlist.append(fname)
             else:
                 no_alias = Alias.blacklist
                 for pdir in path:
                     try:
                         os.chdir(pdir)
                     except OSError:
                         continue
 
                     # for python 3.6+ rewrite to: with os.scandir(pdir) as dirlist:
                     dirlist = os.scandir(pdir)
                     for ff in dirlist:
                         fname = ff.name
                         base, ext = os.path.splitext(fname)
                         if self.isexec(ff) and base.lower() not in no_alias:
                             if ext.lower() == '.exe':
                                 fname = base
                                 try:
                                     # Removes dots from the name since ipython
                                     # will assume names with dots to be python.
                                     self.shell.alias_manager.define_alias(
                                         base.lower().replace('.',''), fname)
                                 except InvalidAliasError:
                                     pass
                                 syscmdlist.append(fname)
 
             self.shell.db['syscmdlist'] = syscmdlist
         finally:
             os.chdir(savedir)
 
     @skip_doctest
     @line_magic
     def pwd(self, parameter_s=''):
         """Return the current working directory path.
 
         Examples
         --------
         ::
 
           In [9]: pwd
           Out[9]: '/home/tsuser/sprint/ipython'
         """
         try:
             return os.getcwd()
         except FileNotFoundError as e:
             raise UsageError("CWD no longer exists - please use %cd to change directory.") from e
 
     @skip_doctest
     @line_magic
     def cd(self, parameter_s=''):
         """Change the current working directory.
 
         This command automatically maintains an internal list of directories
         you visit during your IPython session, in the variable ``_dh``. The
         command :magic:`%dhist` shows this history nicely formatted. You can
         also do ``cd -<tab>`` to see directory history conveniently.
         Usage:
 
           - ``cd 'dir'``: changes to directory 'dir'.
           - ``cd -``: changes to the last visited directory.
           - ``cd -<n>``: changes to the n-th directory in the directory history.
           - ``cd --foo``: change to directory that matches 'foo' in history
           - ``cd -b <bookmark_name>``: jump to a bookmark set by %bookmark
           - Hitting a tab key after ``cd -b`` allows you to tab-complete
             bookmark names.
 
           .. note::
             ``cd <bookmark_name>`` is enough if there is no directory
             ``<bookmark_name>``, but a bookmark with the name exists.
 
 
         Options:
 
         -q               Be quiet. Do not print the working directory after the
                          cd command is executed. By default IPython's cd
                          command does print this directory, since the default
                          prompts do not display path information.
 
         .. note::
            Note that ``!cd`` doesn't work for this purpose because the shell
            where ``!command`` runs is immediately discarded after executing
            'command'.
 
 
         Examples
         --------
         ::
 
           In [10]: cd parent/child
           /home/tsuser/parent/child
         """
 
         try:
             oldcwd = os.getcwd()
         except FileNotFoundError:
             # Happens if the CWD has been deleted.
             oldcwd = None
 
         numcd = re.match(r'(-)(\d+)$',parameter_s)
         # jump in directory history by number
         if numcd:
             nn = int(numcd.group(2))
             try:
                 ps = self.shell.user_ns['_dh'][nn]
             except IndexError:
                 print('The requested directory does not exist in history.')
                 return
             else:
                 opts = {}
         elif parameter_s.startswith('--'):
             ps = None
             fallback = None
             pat = parameter_s[2:]
             dh = self.shell.user_ns['_dh']
             # first search only by basename (last component)
             for ent in reversed(dh):
                 if pat in os.path.basename(ent) and os.path.isdir(ent):
                     ps = ent
                     break
 
                 if fallback is None and pat in ent and os.path.isdir(ent):
                     fallback = ent
 
             # if we have no last part match, pick the first full path match
             if ps is None:
                 ps = fallback
 
             if ps is None:
                 print("No matching entry in directory history")
                 return
             else:
                 opts = {}
 
 
         else:
             opts, ps = self.parse_options(parameter_s, 'qb', mode='string')
         # jump to previous
         if ps == '-':
             try:
                 ps = self.shell.user_ns['_dh'][-2]
             except IndexError as e:
                 raise UsageError('%cd -: No previous directory to change to.') from e
         # jump to bookmark if needed
         else:
             if not os.path.isdir(ps) or 'b' in opts:
                 bkms = self.shell.db.get('bookmarks', {})
 
                 if ps in bkms:
                     target = bkms[ps]
                     print('(bookmark:%s) -> %s' % (ps, target))
                     ps = target
                 else:
                     if 'b' in opts:
                         raise UsageError("Bookmark '%s' not found.  "
                               "Use '%%bookmark -l' to see your bookmarks." % ps)
 
         # at this point ps should point to the target dir
         if ps:
             try:
                 os.chdir(os.path.expanduser(ps))
                 if hasattr(self.shell, 'term_title') and self.shell.term_title:
                     set_term_title(self.shell.term_title_format.format(cwd=abbrev_cwd()))
             except OSError:
                 print(sys.exc_info()[1])
             else:
                 cwd = os.getcwd()
                 dhist = self.shell.user_ns['_dh']
                 if oldcwd != cwd:
                     dhist.append(cwd)
                     self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
 
         else:
             os.chdir(self.shell.home_dir)
             if hasattr(self.shell, 'term_title') and self.shell.term_title:
                 set_term_title(self.shell.term_title_format.format(cwd="~"))
             cwd = os.getcwd()
             dhist = self.shell.user_ns['_dh']
 
             if oldcwd != cwd:
                 dhist.append(cwd)
                 self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
         if not 'q' in opts and not self.cd_force_quiet and self.shell.user_ns['_dh']:
             print(self.shell.user_ns['_dh'][-1])
 
     @line_magic
     def env(self, parameter_s=''):
         """Get, set, or list environment variables.
 
         Usage:\\
 
           :``%env``: lists all environment variables/values
           :``%env var``: get value for var
           :``%env var val``: set value for var
           :``%env var=val``: set value for var
           :``%env var=$val``: set value for var, using python expansion if possible
         """
         if parameter_s.strip():
             split = '=' if '=' in parameter_s else ' '
             bits = parameter_s.split(split)
             if len(bits) == 1:
                 key = parameter_s.strip()
                 if key in os.environ:
                     return os.environ[key]
                 else:
                     err = "Environment does not have key: {0}".format(key)
                     raise UsageError(err)
             if len(bits) > 1:
                 return self.set_env(parameter_s)
         env = dict(os.environ)
         # hide likely secrets when printing the whole environment
         for key in list(env):
             if any(s in key.lower() for s in ('key', 'token', 'secret')):
                 env[key] = '<hidden>'
 
         return env
 
     @line_magic
     def set_env(self, parameter_s):
         """Set environment variables.  Assumptions are that either "val" is a
         name in the user namespace, or val is something that evaluates to a
         string.
 
         Usage:\\
           %set_env var val: set value for var
           %set_env var=val: set value for var
           %set_env var=$val: set value for var, using python expansion if possible
         """
         split = '=' if '=' in parameter_s else ' '
         bits = parameter_s.split(split, 1)
         if not parameter_s.strip() or len(bits)<2:
             raise UsageError("usage is 'set_env var=val'")
         var = bits[0].strip()
         val = bits[1].strip()
         if re.match(r'.*\s.*', var):
             # an environment variable with whitespace is almost certainly
             # not what the user intended.  what's more likely is the wrong
             # split was chosen, ie for "set_env cmd_args A=B", we chose
             # '=' for the split and should have chosen ' '.  to get around
             # this, users should just assign directly to os.environ or use
             # standard magic {var} expansion.
             err = "refusing to set env var with whitespace: '{0}'"
             err = err.format(val)
             raise UsageError(err)
         os.environ[var] = val
         print('env: {0}={1}'.format(var,val))
 
     @line_magic
     def pushd(self, parameter_s=''):
         """Place the current dir on stack and change directory.
 
         Usage:\\
           %pushd ['dirname']
         """
 
         dir_s = self.shell.dir_stack
         tgt = os.path.expanduser(parameter_s)
         cwd = os.getcwd().replace(self.shell.home_dir,'~')
         if tgt:
             self.cd(parameter_s)
         dir_s.insert(0,cwd)
         return self.shell.run_line_magic('dirs', '')
 
     @line_magic
     def popd(self, parameter_s=''):
         """Change to directory popped off the top of the stack.
         """
         if not self.shell.dir_stack:
             raise UsageError("%popd on empty stack")
         top = self.shell.dir_stack.pop(0)
         self.cd(top)
         print("popd ->",top)
 
     @line_magic
     def dirs(self, parameter_s=''):
         """Return the current directory stack."""
 
         return self.shell.dir_stack
 
     @line_magic
     def dhist(self, parameter_s=''):
         """Print your history of visited directories.
 
         %dhist       -> print full history\\
         %dhist n     -> print last n entries only\\
         %dhist n1 n2 -> print entries between n1 and n2 (n2 not included)\\
 
         This history is automatically maintained by the %cd command, and
         always available as the global list variable _dh. You can use %cd -<n>
         to go to directory number <n>.
 
         Note that most of time, you should view directory history by entering
         cd -<TAB>.
 
         """
 
         dh = self.shell.user_ns['_dh']
         if parameter_s:
             try:
                 args = map(int,parameter_s.split())
             except:
                 self.arg_err(self.dhist)
                 return
             if len(args) == 1:
                 ini,fin = max(len(dh)-(args[0]),0),len(dh)
             elif len(args) == 2:
                 ini,fin = args
                 fin = min(fin, len(dh))
             else:
                 self.arg_err(self.dhist)
                 return
         else:
             ini,fin = 0,len(dh)
         print('Directory history (kept in _dh)')
         for i in range(ini, fin):
             print("%d: %s" % (i, dh[i]))
 
     @skip_doctest
     @line_magic
     def sc(self, parameter_s=''):
         """Shell capture - run shell command and capture output (DEPRECATED use !).
 
         DEPRECATED. Suboptimal, retained for backwards compatibility.
 
         You should use the form 'var = !command' instead. Example:
 
          "%sc -l myfiles = ls ~" should now be written as
 
          "myfiles = !ls ~"
 
         myfiles.s, myfiles.l and myfiles.n still apply as documented
         below.
 
         --
         %sc [options] varname=command
 
         IPython will run the given command using commands.getoutput(), and
         will then update the user's interactive namespace with a variable
         called varname, containing the value of the call.  Your command can
         contain shell wildcards, pipes, etc.
 
         The '=' sign in the syntax is mandatory, and the variable name you
         supply must follow Python's standard conventions for valid names.
 
         (A special format without variable name exists for internal use)
 
         Options:
 
           -l: list output.  Split the output on newlines into a list before
           assigning it to the given variable.  By default the output is stored
           as a single string.
 
           -v: verbose.  Print the contents of the variable.
 
         In most cases you should not need to split as a list, because the
         returned value is a special type of string which can automatically
         provide its contents either as a list (split on newlines) or as a
         space-separated string.  These are convenient, respectively, either
         for sequential processing or to be passed to a shell command.
 
         For example::
 
             # Capture into variable a
             In [1]: sc a=ls *py
 
             # a is a string with embedded newlines
             In [2]: a
             Out[2]: 'setup.py\\nwin32_manual_post_install.py'
 
             # which can be seen as a list:
             In [3]: a.l
             Out[3]: ['setup.py', 'win32_manual_post_install.py']
 
             # or as a whitespace-separated string:
             In [4]: a.s
             Out[4]: 'setup.py win32_manual_post_install.py'
 
             # a.s is useful to pass as a single command line:
             In [5]: !wc -l $a.s
               146 setup.py
               130 win32_manual_post_install.py
               276 total
 
             # while the list form is useful to loop over:
             In [6]: for f in a.l:
               ...:      !wc -l $f
               ...:
             146 setup.py
             130 win32_manual_post_install.py
 
         Similarly, the lists returned by the -l option are also special, in
         the sense that you can equally invoke the .s attribute on them to
         automatically get a whitespace-separated string from their contents::
 
             In [7]: sc -l b=ls *py
 
             In [8]: b
             Out[8]: ['setup.py', 'win32_manual_post_install.py']
 
             In [9]: b.s
             Out[9]: 'setup.py win32_manual_post_install.py'
 
         In summary, both the lists and strings used for output capture have
         the following special attributes::
 
             .l (or .list) : value as list.
             .n (or .nlstr): value as newline-separated string.
             .s (or .spstr): value as space-separated string.
         """
 
         opts,args = self.parse_options(parameter_s, 'lv')
         # Try to get a variable name and command to run
         try:
             # the variable name must be obtained from the parse_options
             # output, which uses shlex.split to strip options out.
             var,_ = args.split('=', 1)
             var = var.strip()
             # But the command has to be extracted from the original input
             # parameter_s, not on what parse_options returns, to avoid the
             # quote stripping which shlex.split performs on it.
             _,cmd = parameter_s.split('=', 1)
         except ValueError:
             var,cmd = '',''
         # If all looks ok, proceed
         split = 'l' in opts
         out = self.shell.getoutput(cmd, split=split)
         if 'v' in opts:
             print('%s ==\n%s' % (var, pformat(out)))
         if var:
             self.shell.user_ns.update({var:out})
         else:
             return out
 
     @line_cell_magic
     def sx(self, line='', cell=None):
         """Shell execute - run shell command and capture output (!! is short-hand).
 
         %sx command
 
         IPython will run the given command using commands.getoutput(), and
         return the result formatted as a list (split on '\\n').  Since the
         output is _returned_, it will be stored in ipython's regular output
         cache Out[N] and in the '_N' automatic variables.
 
         Notes:
 
         1) If an input line begins with '!!', then %sx is automatically
         invoked.  That is, while::
 
           !ls
 
         causes ipython to simply issue system('ls'), typing::
 
           !!ls
 
         is a shorthand equivalent to::
 
           %sx ls
 
         2) %sx differs from %sc in that %sx automatically splits into a list,
         like '%sc -l'.  The reason for this is to make it as easy as possible
         to process line-oriented shell output via further python commands.
         %sc is meant to provide much finer control, but requires more
         typing.
 
         3) Just like %sc -l, this is a list with special attributes:
         ::
 
           .l (or .list) : value as list.
           .n (or .nlstr): value as newline-separated string.
           .s (or .spstr): value as whitespace-separated string.
 
         This is very useful when trying to use such lists as arguments to
         system commands."""
         
         if cell is None:
             # line magic
             return self.shell.getoutput(line)
         else:
             opts,args = self.parse_options(line, '', 'out=')
             output = self.shell.getoutput(cell)
             out_name = opts.get('out', opts.get('o'))
             if out_name:
                 self.shell.user_ns[out_name] = output
             else:
                 return output
 
     system = line_cell_magic('system')(sx)
     bang = cell_magic('!')(sx)
 
     @line_magic
     def bookmark(self, parameter_s=''):
         """Manage IPython's bookmark system.
 
         %bookmark <name>       - set bookmark to current dir
         %bookmark <name> <dir> - set bookmark to <dir>
         %bookmark -l           - list all bookmarks
         %bookmark -d <name>    - remove bookmark
         %bookmark -r           - remove all bookmarks
 
         You can later on access a bookmarked folder with::
 
           %cd -b <name>
 
         or simply '%cd <name>' if there is no directory called <name> AND
         there is such a bookmark defined.
 
         Your bookmarks persist through IPython sessions, but they are
         associated with each profile."""
 
         opts,args = self.parse_options(parameter_s,'drl',mode='list')
         if len(args) > 2:
             raise UsageError("%bookmark: too many arguments")
 
         bkms = self.shell.db.get('bookmarks',{})
 
         if 'd' in opts:
             try:
                 todel = args[0]
             except IndexError as e:
                 raise UsageError(
                     "%bookmark -d: must provide a bookmark to delete") from e
             else:
                 try:
                     del bkms[todel]
                 except KeyError as e:
                     raise UsageError(
                         "%%bookmark -d: Can't delete bookmark '%s'" % todel) from e
 
         elif 'r' in opts:
             bkms = {}
         elif 'l' in opts:
             bks = sorted(bkms)
             if bks:
                 size = max(map(len, bks))
             else:
                 size = 0
             fmt = '%-'+str(size)+'s -> %s'
             print('Current bookmarks:')
             for bk in bks:
                 print(fmt % (bk, bkms[bk]))
         else:
             if not args:
                 raise UsageError("%bookmark: You must specify the bookmark name")
             elif len(args)==1:
                 bkms[args[0]] = os.getcwd()
             elif len(args)==2:
                 bkms[args[0]] = args[1]
         self.shell.db['bookmarks'] = bkms
 
     @line_magic
     def pycat(self, parameter_s=''):
         """Show a syntax-highlighted file through a pager.
 
         This magic is similar to the cat utility, but it will assume the file
         to be Python source and will show it with syntax highlighting.
 
         This magic command can either take a local filename, an url,
-        an history range (see %history) or a macro as argument ::
+        an history range (see %history) or a macro as argument.
+
+        If no parameter is given, prints out history of current session up to
+        this point. ::
 
         %pycat myscript.py
         %pycat 7-27
         %pycat myMacro
         %pycat http://www.example.com/myscript.py
         """
-        if not parameter_s:
-            raise UsageError('Missing filename, URL, input history range, '
-                             'or macro.')
-
-        try :
+        try:
             cont = self.shell.find_user_code(parameter_s, skip_encoding_cookie=False)
         except (ValueError, IOError):
             print("Error: no such file, variable, URL, history range or macro")
             return
 
         page.page(self.shell.pycolorize(source_to_unicode(cont)))
 
     @magic_arguments.magic_arguments()
     @magic_arguments.argument(
         '-a', '--append', action='store_true', default=False,
         help='Append contents of the cell to an existing file. '
              'The file will be created if it does not exist.'
     )
     @magic_arguments.argument(
         'filename', type=str,
         help='file to write'
     )
     @cell_magic
     def writefile(self, line, cell):
         """Write the contents of the cell to a file.
         
         The file will be overwritten unless the -a (--append) flag is specified.
         """
         args = magic_arguments.parse_argstring(self.writefile, line)
         if re.match(r'^(\'.*\')|(".*")$', args.filename):
             filename = os.path.expanduser(args.filename[1:-1])
         else:
             filename = os.path.expanduser(args.filename)
             
         if os.path.exists(filename):
             if args.append:
                 print("Appending to %s" % filename)
             else:
                 print("Overwriting %s" % filename)
         else:
             print("Writing %s" % filename)
         
         mode = 'a' if args.append else 'w'
         with io.open(filename, mode, encoding='utf-8') as f:
             f.write(cell)

IPython/core/tests/test_history.py

@@ -1,215 +1,223 b''
 # coding: utf-8
 """Tests for the IPython tab-completion machinery.
 """
 #-----------------------------------------------------------------------------
 # Module imports
 #-----------------------------------------------------------------------------
 
 # stdlib
 import io
 from pathlib import Path
 import sys
 import tempfile
 from datetime import datetime
 import sqlite3
 
 # third party
 import nose.tools as nt
 
 # our own packages
 from traitlets.config.loader import Config
 from IPython.utils.tempdir import TemporaryDirectory
 from IPython.core.history import HistoryManager, extract_hist_ranges
 from IPython.testing.decorators import skipif
 
 def test_proper_default_encoding():
     nt.assert_equal(sys.getdefaultencoding(), "utf-8")
 
 @skipif(sqlite3.sqlite_version_info > (3,24,0))
 def test_history():
     ip = get_ipython()
     with TemporaryDirectory() as tmpdir:
         tmp_path = Path(tmpdir)
         hist_manager_ori = ip.history_manager
         hist_file = tmp_path / "history.sqlite"
         try:
             ip.history_manager = HistoryManager(shell=ip, hist_file=hist_file)
             hist = [u'a=1', u'def f():\n    test = 1\n    return test', u"b='€Æ¾÷ß'"]
             for i, h in enumerate(hist, start=1):
                 ip.history_manager.store_inputs(i, h)
 
             ip.history_manager.db_log_output = True
             # Doesn't match the input, but we'll just check it's stored.
             ip.history_manager.output_hist_reprs[3] = "spam"
             ip.history_manager.store_output(3)
 
             nt.assert_equal(ip.history_manager.input_hist_raw, [''] + hist)
 
             # Detailed tests for _get_range_session
             grs = ip.history_manager._get_range_session
             nt.assert_equal(list(grs(start=2,stop=-1)), list(zip([0], [2], hist[1:-1])))
             nt.assert_equal(list(grs(start=-2)), list(zip([0,0], [2,3], hist[-2:])))
             nt.assert_equal(list(grs(output=True)), list(zip([0,0,0], [1,2,3], zip(hist, [None,None,'spam']))))
 
             # Check whether specifying a range beyond the end of the current
             # session results in an error (gh-804)
             ip.magic('%hist 2-500')
 
             # Check that we can write non-ascii characters to a file
             ip.magic("%%hist -f %s" % (tmp_path / "test1"))
             ip.magic("%%hist -pf %s" % (tmp_path / "test2"))
             ip.magic("%%hist -nf %s" % (tmp_path / "test3"))
             ip.magic("%%save %s 1-10" % (tmp_path / "test4"))
 
             # New session
             ip.history_manager.reset()
             newcmds = [u"z=5",
                        u"class X(object):\n    pass",
                        u"k='p'",
                        u"z=5"]
             for i, cmd in enumerate(newcmds, start=1):
                 ip.history_manager.store_inputs(i, cmd)
             gothist = ip.history_manager.get_range(start=1, stop=4)
             nt.assert_equal(list(gothist), list(zip([0,0,0],[1,2,3], newcmds)))
             # Previous session:
             gothist = ip.history_manager.get_range(-1, 1, 4)
             nt.assert_equal(list(gothist), list(zip([1,1,1],[1,2,3], hist)))
 
             newhist = [(2, i, c) for (i, c) in enumerate(newcmds, 1)]
 
             # Check get_hist_tail
             gothist = ip.history_manager.get_tail(5, output=True,
                                                     include_latest=True)
             expected = [(1, 3, (hist[-1], "spam"))] \
                 + [(s, n, (c, None)) for (s, n, c) in newhist]
             nt.assert_equal(list(gothist), expected)
 
             gothist = ip.history_manager.get_tail(2)
             expected = newhist[-3:-1]
             nt.assert_equal(list(gothist), expected)
 
             # Check get_hist_search
 
             gothist = ip.history_manager.search("*test*")
             nt.assert_equal(list(gothist), [(1,2,hist[1])] )
 
             gothist = ip.history_manager.search("*=*")
             nt.assert_equal(list(gothist),
                             [(1, 1, hist[0]),
                              (1, 2, hist[1]),
                              (1, 3, hist[2]),
                              newhist[0],
                              newhist[2],
                              newhist[3]])
 
             gothist = ip.history_manager.search("*=*", n=4)
             nt.assert_equal(list(gothist),
                             [(1, 3, hist[2]),
                              newhist[0],
                              newhist[2],
                              newhist[3]])
 
             gothist = ip.history_manager.search("*=*", unique=True)
             nt.assert_equal(list(gothist),
                             [(1, 1, hist[0]),
                              (1, 2, hist[1]),
                              (1, 3, hist[2]),
                              newhist[2],
                              newhist[3]])
 
             gothist = ip.history_manager.search("*=*", unique=True, n=3)
             nt.assert_equal(list(gothist),
                             [(1, 3, hist[2]),
                              newhist[2],
                              newhist[3]])
 
             gothist = ip.history_manager.search("b*", output=True)
             nt.assert_equal(list(gothist), [(1,3,(hist[2],"spam"))] )
 
             # Cross testing: check that magic %save can get previous session.
             testfilename = (tmp_path / "test.py").resolve()
             ip.magic("save " + str(testfilename) + " ~1/1-3")
             with io.open(testfilename, encoding='utf-8') as testfile:
                 nt.assert_equal(testfile.read(),
                                         u"# coding: utf-8\n" + u"\n".join(hist)+u"\n")
 
             # Duplicate line numbers - check that it doesn't crash, and
             # gets a new session
             ip.history_manager.store_inputs(1, "rogue")
             ip.history_manager.writeout_cache()
             nt.assert_equal(ip.history_manager.session_number, 3)
         finally:
             # Ensure saving thread is shut down before we try to clean up the files
             ip.history_manager.save_thread.stop()
             # Forcibly close database rather than relying on garbage collection
             ip.history_manager.db.close()
             # Restore history manager
             ip.history_manager = hist_manager_ori
 
 
 def test_extract_hist_ranges():
     instr = "1 2/3 ~4/5-6 ~4/7-~4/9 ~9/2-~7/5 ~10/"
     expected = [(0, 1, 2),  # 0 == current session
                 (2, 3, 4),
                 (-4, 5, 7),
                 (-4, 7, 10),
                 (-9, 2, None),  # None == to end
                 (-8, 1, None),
                 (-7, 1, 6),
                 (-10, 1, None)]
     actual = list(extract_hist_ranges(instr))
     nt.assert_equal(actual, expected)
 
+
+def test_extract_hist_ranges_empty_str():
+    instr = ""
+    expected = [(0, 1, None)]  # 0 == current session, None == to end
+    actual = list(extract_hist_ranges(instr))
+    nt.assert_equal(actual, expected)
+
+
 def test_magic_rerun():
     """Simple test for %rerun (no args -> rerun last line)"""
     ip = get_ipython()
     ip.run_cell("a = 10", store_history=True)
     ip.run_cell("a += 1", store_history=True)
     nt.assert_equal(ip.user_ns["a"], 11)
     ip.run_cell("%rerun", store_history=True)
     nt.assert_equal(ip.user_ns["a"], 12)
 
 def test_timestamp_type():
     ip = get_ipython()
     info = ip.history_manager.get_session_info()
     nt.assert_true(isinstance(info[1], datetime))
 
 def test_hist_file_config():
     cfg = Config()
     tfile = tempfile.NamedTemporaryFile(delete=False)
     cfg.HistoryManager.hist_file = Path(tfile.name)
     try:
         hm = HistoryManager(shell=get_ipython(), config=cfg)
         nt.assert_equal(hm.hist_file, cfg.HistoryManager.hist_file)
     finally:
         try:
             Path(tfile.name).unlink()
         except OSError:
             # same catch as in testing.tools.TempFileMixin
             # On Windows, even though we close the file, we still can't
             # delete it.  I have no clue why
             pass
 
 def test_histmanager_disabled():
     """Ensure that disabling the history manager doesn't create a database."""
     cfg = Config()
     cfg.HistoryAccessor.enabled = False
 
     ip = get_ipython()
     with TemporaryDirectory() as tmpdir:
         hist_manager_ori = ip.history_manager
         hist_file = Path(tmpdir) / "history.sqlite"
         cfg.HistoryManager.hist_file = hist_file
         try:
             ip.history_manager = HistoryManager(shell=ip, config=cfg)
             hist = [u'a=1', u'def f():\n    test = 1\n    return test', u"b='€Æ¾÷ß'"]
             for i, h in enumerate(hist, start=1):
                 ip.history_manager.store_inputs(i, h)
             nt.assert_equal(ip.history_manager.input_hist_raw, [''] + hist)
             ip.history_manager.reset()
             ip.history_manager.end_session()
         finally:
             ip.history_manager = hist_manager_ori
 
     # hist_file should not be created
     nt.assert_false(hist_file.exists())

IPython/core/tests/test_magic.py

@@ -1,1279 +1,1302 b''
 # -*- coding: utf-8 -*-
 """Tests for various magic functions.
 
 Needs to be run by nose (to make ipython session available).
 """
 
 import io
 import os
 import re
 import sys
 import warnings
 from textwrap import dedent
 from unittest import TestCase
 from unittest import mock
 from importlib import invalidate_caches
 from io import StringIO
 from pathlib import Path
 
 import nose.tools as nt
 
 import shlex
 
 from IPython import get_ipython
 from IPython.core import magic
 from IPython.core.error import UsageError
 from IPython.core.magic import (Magics, magics_class, line_magic,
                                 cell_magic,
                                 register_line_magic, register_cell_magic)
 from IPython.core.magics import execution, script, code, logging, osm
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 from IPython.utils.io import capture_output
 from IPython.utils.tempdir import (TemporaryDirectory,
                                     TemporaryWorkingDirectory)
 from IPython.utils.process import find_cmd
 from .test_debugger import PdbTestInput
 
 import pytest
 
 
 @magic.magics_class
 class DummyMagics(magic.Magics): pass
 
 def test_extract_code_ranges():
     instr = "1 3 5-6 7-9 10:15 17: :10 10- -13 :"
     expected = [(0, 1), 
                 (2, 3),
                 (4, 6),
                 (6, 9),
                 (9, 14),
                 (16, None),
                 (None, 9),
                 (9, None),
                 (None, 13),
                 (None, None)]
     actual = list(code.extract_code_ranges(instr))
     nt.assert_equal(actual, expected)
 
 def test_extract_symbols():
     source = """import foo\na = 10\ndef b():\n    return 42\n\n\nclass A: pass\n\n\n"""
     symbols_args = ["a", "b", "A", "A,b", "A,a", "z"]
     expected = [([], ['a']),
                 (["def b():\n    return 42\n"], []),
                 (["class A: pass\n"], []),
                 (["class A: pass\n", "def b():\n    return 42\n"], []),
                 (["class A: pass\n"], ['a']),
                 ([], ['z'])]
     for symbols, exp in zip(symbols_args, expected):
         nt.assert_equal(code.extract_symbols(source, symbols), exp)
 
 
 def test_extract_symbols_raises_exception_with_non_python_code():
     source = ("=begin A Ruby program :)=end\n"
               "def hello\n"
               "puts 'Hello world'\n"
               "end")
     with nt.assert_raises(SyntaxError):
         code.extract_symbols(source, "hello")
 
 
 def test_magic_not_found():
     # magic not found raises UsageError
     with nt.assert_raises(UsageError):
         _ip.magic('doesntexist')
 
     # ensure result isn't success when a magic isn't found
     result = _ip.run_cell('%doesntexist')
     assert isinstance(result.error_in_exec, UsageError)
 
 
 def test_cell_magic_not_found():
     # magic not found raises UsageError
     with nt.assert_raises(UsageError):
         _ip.run_cell_magic('doesntexist', 'line', 'cell')
 
     # ensure result isn't success when a magic isn't found
     result = _ip.run_cell('%%doesntexist')
     assert isinstance(result.error_in_exec, UsageError)
 
 
 def test_magic_error_status():
     def fail(shell):
         1/0
     _ip.register_magic_function(fail)
     result = _ip.run_cell('%fail')
     assert isinstance(result.error_in_exec, ZeroDivisionError)
 
 
 def test_config():
     """ test that config magic does not raise
     can happen if Configurable init is moved too early into
     Magics.__init__ as then a Config object will be registered as a
     magic.
     """
     ## should not raise.
     _ip.magic('config')
 
 def test_config_available_configs():
     """ test that config magic prints available configs in unique and
     sorted order. """
     with capture_output() as captured:
         _ip.magic('config')
 
     stdout = captured.stdout
     config_classes = stdout.strip().split('\n')[1:]
     nt.assert_list_equal(config_classes, sorted(set(config_classes)))
 
 def test_config_print_class():
     """ test that config with a classname prints the class's options. """
     with capture_output() as captured:
         _ip.magic('config TerminalInteractiveShell')
 
     stdout = captured.stdout
     if not re.match("TerminalInteractiveShell.* options", stdout.splitlines()[0]):
         print(stdout)
         raise AssertionError("1st line of stdout not like "
                              "'TerminalInteractiveShell.* options'")
 
 def test_rehashx():
     # clear up everything
     _ip.alias_manager.clear_aliases()
     del _ip.db['syscmdlist']
     
     _ip.magic('rehashx')
     # Practically ALL ipython development systems will have more than 10 aliases
 
     nt.assert_true(len(_ip.alias_manager.aliases) > 10)
     for name, cmd in _ip.alias_manager.aliases:
         # we must strip dots from alias names
         nt.assert_not_in('.', name)
 
     # rehashx must fill up syscmdlist
     scoms = _ip.db['syscmdlist']
     nt.assert_true(len(scoms) > 10)
             
 
 
 def test_magic_parse_options():
     """Test that we don't mangle paths when parsing magic options."""
     ip = get_ipython()
     path = 'c:\\x'
     m = DummyMagics(ip)
     opts = m.parse_options('-f %s' % path,'f:')[0]
     # argv splitting is os-dependent
     if os.name == 'posix':
         expected = 'c:x'
     else:
         expected = path
     nt.assert_equal(opts['f'], expected)
 
 def test_magic_parse_long_options():
     """Magic.parse_options can handle --foo=bar long options"""
     ip = get_ipython()
     m = DummyMagics(ip)
     opts, _ = m.parse_options('--foo --bar=bubble', 'a', 'foo', 'bar=')
     nt.assert_in('foo', opts)
     nt.assert_in('bar', opts)
     nt.assert_equal(opts['bar'], "bubble")
 
 
 def doctest_hist_f():
     """Test %hist -f with temporary filename.
 
     In [9]: import tempfile
 
     In [10]: tfile = tempfile.mktemp('.py','tmp-ipython-')
 
     In [11]: %hist -nl -f $tfile 3
 
     In [13]: import os; os.unlink(tfile)
     """
 
 
 def doctest_hist_op():
     """Test %hist -op
 
     In [1]: class b(float):
        ...:     pass
        ...: 
 
     In [2]: class s(object):
        ...:     def __str__(self):
        ...:         return 's'
        ...: 
 
     In [3]: 
 
     In [4]: class r(b):
        ...:     def __repr__(self):
        ...:         return 'r'
        ...: 
 
     In [5]: class sr(s,r): pass
        ...: 
 
     In [6]: 
 
     In [7]: bb=b()
 
     In [8]: ss=s()
 
     In [9]: rr=r()
 
     In [10]: ssrr=sr()
 
     In [11]: 4.5
     Out[11]: 4.5
 
     In [12]: str(ss)
     Out[12]: 's'
 
     In [13]: 
 
     In [14]: %hist -op
     >>> class b:
     ...     pass
     ... 
     >>> class s(b):
     ...     def __str__(self):
     ...         return 's'
     ... 
     >>> 
     >>> class r(b):
     ...     def __repr__(self):
     ...         return 'r'
     ... 
     >>> class sr(s,r): pass
     >>> 
     >>> bb=b()
     >>> ss=s()
     >>> rr=r()
     >>> ssrr=sr()
     >>> 4.5
     4.5
     >>> str(ss)
     's'
     >>> 
     """
 
 def test_hist_pof():
     ip = get_ipython()
     ip.run_cell(u"1+2", store_history=True)
     #raise Exception(ip.history_manager.session_number)
     #raise Exception(list(ip.history_manager._get_range_session()))
     with TemporaryDirectory() as td:
         tf = os.path.join(td, 'hist.py')
         ip.run_line_magic('history', '-pof %s' % tf)
         assert os.path.isfile(tf)
 
 
 def test_macro():
     ip = get_ipython()
     ip.history_manager.reset()   # Clear any existing history.
     cmds = ["a=1", "def b():\n  return a**2", "print(a,b())"]
     for i, cmd in enumerate(cmds, start=1):
         ip.history_manager.store_inputs(i, cmd)
     ip.magic("macro test 1-3")
     nt.assert_equal(ip.user_ns["test"].value, "\n".join(cmds)+"\n")
     
     # List macros
     nt.assert_in("test", ip.magic("macro"))
 
 
 def test_macro_run():
     """Test that we can run a multi-line macro successfully."""
     ip = get_ipython()
     ip.history_manager.reset()
     cmds = ["a=10", "a+=1", "print(a)", "%macro test 2-3"]
     for cmd in cmds:
         ip.run_cell(cmd, store_history=True)
     nt.assert_equal(ip.user_ns["test"].value, "a+=1\nprint(a)\n")
     with tt.AssertPrints("12"):
         ip.run_cell("test")
     with tt.AssertPrints("13"):
         ip.run_cell("test")
 
 
 def test_magic_magic():
     """Test %magic"""
     ip = get_ipython()
     with capture_output() as captured:
         ip.magic("magic")
     
     stdout = captured.stdout
     nt.assert_in('%magic', stdout)
     nt.assert_in('IPython', stdout)
     nt.assert_in('Available', stdout)
 
 
 @dec.skipif_not_numpy
 def test_numpy_reset_array_undec():
     "Test '%reset array' functionality"
     _ip.ex('import numpy as np')
     _ip.ex('a = np.empty(2)')
     nt.assert_in('a', _ip.user_ns)
     _ip.magic('reset -f array')
     nt.assert_not_in('a', _ip.user_ns)
 
 def test_reset_out():
     "Test '%reset out' magic"
     _ip.run_cell("parrot = 'dead'", store_history=True)
     # test '%reset -f out', make an Out prompt
     _ip.run_cell("parrot", store_history=True)
     nt.assert_true('dead' in [_ip.user_ns[x] for x in ('_','__','___')])
     _ip.magic('reset -f out')
     nt.assert_false('dead' in [_ip.user_ns[x] for x in ('_','__','___')])
     nt.assert_equal(len(_ip.user_ns['Out']), 0)
 
 def test_reset_in():
     "Test '%reset in' magic"
     # test '%reset -f in'
     _ip.run_cell("parrot", store_history=True)
     nt.assert_true('parrot' in [_ip.user_ns[x] for x in ('_i','_ii','_iii')])
     _ip.magic('%reset -f in')
     nt.assert_false('parrot' in [_ip.user_ns[x] for x in ('_i','_ii','_iii')])
     nt.assert_equal(len(set(_ip.user_ns['In'])), 1)
 
 def test_reset_dhist():
     "Test '%reset dhist' magic"
     _ip.run_cell("tmp = [d for d in _dh]") # copy before clearing
     _ip.magic('cd ' + os.path.dirname(nt.__file__))
     _ip.magic('cd -')
     nt.assert_true(len(_ip.user_ns['_dh']) > 0)
     _ip.magic('reset -f dhist')
     nt.assert_equal(len(_ip.user_ns['_dh']), 0)
     _ip.run_cell("_dh = [d for d in tmp]") #restore
 
 def test_reset_in_length():
     "Test that '%reset in' preserves In[] length"
     _ip.run_cell("print 'foo'")
     _ip.run_cell("reset -f in")
     nt.assert_equal(len(_ip.user_ns['In']), _ip.displayhook.prompt_count+1)
 
 class TestResetErrors(TestCase):
 
     def test_reset_redefine(self):
 
         @magics_class
         class KernelMagics(Magics):
               @line_magic
               def less(self, shell): pass
 
         _ip.register_magics(KernelMagics)
 
         with self.assertLogs() as cm:
             # hack, we want to just capture logs, but assertLogs fails if not
             # logs get produce.
             # so log one things we ignore.
             import logging as log_mod
             log = log_mod.getLogger()
             log.info('Nothing')
             # end hack.
             _ip.run_cell("reset -f")
 
         assert len(cm.output) == 1
         for out in cm.output:
             assert "Invalid alias" not in out
 
 def test_tb_syntaxerror():
     """test %tb after a SyntaxError"""
     ip = get_ipython()
     ip.run_cell("for")
     
     # trap and validate stdout
     save_stdout = sys.stdout
     try:
         sys.stdout = StringIO()
         ip.run_cell("%tb")
         out = sys.stdout.getvalue()
     finally:
         sys.stdout = save_stdout
     # trim output, and only check the last line
     last_line = out.rstrip().splitlines()[-1].strip()
     nt.assert_equal(last_line, "SyntaxError: invalid syntax")
 
 
 def test_time():
     ip = get_ipython()
     
     with tt.AssertPrints("Wall time: "):
         ip.run_cell("%time None")
     
     ip.run_cell("def f(kmjy):\n"
                 "    %time print (2*kmjy)")
     
     with tt.AssertPrints("Wall time: "):
         with tt.AssertPrints("hihi", suppress=False):
             ip.run_cell("f('hi')")
 
 def test_time_last_not_expression():
     ip.run_cell("%%time\n"
                 "var_1 = 1\n"
                 "var_2 = 2\n")
     assert ip.user_ns['var_1'] == 1
     del ip.user_ns['var_1']
     assert ip.user_ns['var_2'] == 2
     del ip.user_ns['var_2']
     
 
 @dec.skip_win32
 def test_time2():
     ip = get_ipython()
     
     with tt.AssertPrints("CPU times: user "):
         ip.run_cell("%time None")
 
 def test_time3():
     """Erroneous magic function calls, issue gh-3334"""
     ip = get_ipython()
     ip.user_ns.pop('run', None)
     
     with tt.AssertNotPrints("not found", channel='stderr'):
         ip.run_cell("%%time\n"
                     "run = 0\n"
                     "run += 1")
 
 def test_multiline_time():
     """Make sure last statement from time return a value."""
     ip = get_ipython()
     ip.user_ns.pop('run', None)
 
     ip.run_cell(dedent("""\
         %%time
         a = "ho"
         b = "hey"
         a+b
         """))
     nt.assert_equal(ip.user_ns_hidden['_'], 'hohey')
 
 def test_time_local_ns():
     """
     Test that local_ns is actually global_ns when running a cell magic
     """
     ip = get_ipython()
     ip.run_cell("%%time\n"
                 "myvar = 1")
     nt.assert_equal(ip.user_ns['myvar'], 1)
     del ip.user_ns['myvar']
 
 def test_doctest_mode():
     "Toggle doctest_mode twice, it should be a no-op and run without error"
     _ip.magic('doctest_mode')
     _ip.magic('doctest_mode')
 
 
 def test_parse_options():
     """Tests for basic options parsing in magics."""
     # These are only the most minimal of tests, more should be added later.  At
     # the very least we check that basic text/unicode calls work OK.
     m = DummyMagics(_ip)
     nt.assert_equal(m.parse_options('foo', '')[1], 'foo')
     nt.assert_equal(m.parse_options(u'foo', '')[1], u'foo')
 
 
 def test_parse_options_preserve_non_option_string():
     """Test to assert preservation of non-option part of magic-block, while parsing magic options."""
     m = DummyMagics(_ip)
     opts, stmt = m.parse_options(
         " -n1  -r 13 _ = 314 + foo", "n:r:", preserve_non_opts=True
     )
     nt.assert_equal(opts, {"n": "1", "r": "13"})
     nt.assert_equal(stmt, "_ = 314 + foo")
 
 
 def test_run_magic_preserve_code_block():
     """Test to assert preservation of non-option part of magic-block, while running magic."""
     _ip.user_ns["spaces"] = []
     _ip.magic("timeit -n1 -r1 spaces.append([s.count(' ') for s in ['document']])")
     assert _ip.user_ns["spaces"] == [[0]]
 
 
 def test_dirops():
     """Test various directory handling operations."""
     # curpath = lambda :os.path.splitdrive(os.getcwd())[1].replace('\\','/')
     curpath = os.getcwd
     startdir = os.getcwd()
     ipdir = os.path.realpath(_ip.ipython_dir)
     try:
         _ip.magic('cd "%s"' % ipdir)
         nt.assert_equal(curpath(), ipdir)
         _ip.magic('cd -')
         nt.assert_equal(curpath(), startdir)
         _ip.magic('pushd "%s"' % ipdir)
         nt.assert_equal(curpath(), ipdir)
         _ip.magic('popd')
         nt.assert_equal(curpath(), startdir)
     finally:
         os.chdir(startdir)
 
 
 def test_cd_force_quiet():
     """Test OSMagics.cd_force_quiet option"""
     _ip.config.OSMagics.cd_force_quiet = True
     osmagics = osm.OSMagics(shell=_ip)
 
     startdir = os.getcwd()
     ipdir = os.path.realpath(_ip.ipython_dir)
 
     try:
         with tt.AssertNotPrints(ipdir):
             osmagics.cd('"%s"' % ipdir)
         with tt.AssertNotPrints(startdir):
             osmagics.cd('-')
     finally:
         os.chdir(startdir)
 
 
 def test_xmode():
     # Calling xmode three times should be a no-op
     xmode = _ip.InteractiveTB.mode
     for i in range(4):
         _ip.magic("xmode")
     nt.assert_equal(_ip.InteractiveTB.mode, xmode)
     
 def test_reset_hard():
     monitor = []
     class A(object):
         def __del__(self):
             monitor.append(1)
         def __repr__(self):
             return "<A instance>"
             
     _ip.user_ns["a"] = A()
     _ip.run_cell("a")
     
     nt.assert_equal(monitor, [])
     _ip.magic("reset -f")
     nt.assert_equal(monitor, [1])
     
 class TestXdel(tt.TempFileMixin):
     def test_xdel(self):
         """Test that references from %run are cleared by xdel."""
         src = ("class A(object):\n"
                "    monitor = []\n"
                "    def __del__(self):\n"
                "        self.monitor.append(1)\n"
                "a = A()\n")
         self.mktmp(src)
         # %run creates some hidden references...
         _ip.magic("run %s" % self.fname)
         # ... as does the displayhook.
         _ip.run_cell("a")
         
         monitor = _ip.user_ns["A"].monitor
         nt.assert_equal(monitor, [])
         
         _ip.magic("xdel a")
         
         # Check that a's __del__ method has been called.
         nt.assert_equal(monitor, [1])
 
 def doctest_who():
     """doctest for %who
     
     In [1]: %reset -f
     
     In [2]: alpha = 123
     
     In [3]: beta = 'beta'
     
     In [4]: %who int
     alpha
     
     In [5]: %who str
     beta
     
     In [6]: %whos
     Variable   Type    Data/Info
     ----------------------------
     alpha      int     123
     beta       str     beta
     
     In [7]: %who_ls
     Out[7]: ['alpha', 'beta']
     """
 
 def test_whos():
     """Check that whos is protected against objects where repr() fails."""
     class A(object):
         def __repr__(self):
             raise Exception()
     _ip.user_ns['a'] = A()
     _ip.magic("whos")
 
 def doctest_precision():
     """doctest for %precision
     
     In [1]: f = get_ipython().display_formatter.formatters['text/plain']
     
     In [2]: %precision 5
     Out[2]: '%.5f'
     
     In [3]: f.float_format
     Out[3]: '%.5f'
     
     In [4]: %precision %e
     Out[4]: '%e'
     
     In [5]: f(3.1415927)
     Out[5]: '3.141593e+00'
     """
 
 def test_debug_magic():
     """Test debugging a small code with %debug
     
     In [1]: with PdbTestInput(['c']):
        ...:     %debug print("a b") #doctest: +ELLIPSIS
        ...:
     ...
     ipdb> c
     a b
     In [2]:
     """
 
 def test_psearch():
     with tt.AssertPrints("dict.fromkeys"):
         _ip.run_cell("dict.fr*?")
     with tt.AssertPrints("π.is_integer"):
         _ip.run_cell("π = 3.14;\nπ.is_integ*?")
 
 def test_timeit_shlex():
     """test shlex issues with timeit (#1109)"""
     _ip.ex("def f(*a,**kw): pass")
     _ip.magic('timeit -n1 "this is a bug".count(" ")')
     _ip.magic('timeit -r1 -n1 f(" ", 1)')
     _ip.magic('timeit -r1 -n1 f(" ", 1, " ", 2, " ")')
     _ip.magic('timeit -r1 -n1 ("a " + "b")')
     _ip.magic('timeit -r1 -n1 f("a " + "b")')
     _ip.magic('timeit -r1 -n1 f("a " + "b ")')
 
 
 def test_timeit_special_syntax():
     "Test %%timeit with IPython special syntax"
     @register_line_magic
     def lmagic(line):
         ip = get_ipython()
         ip.user_ns['lmagic_out'] = line
 
     # line mode test
     _ip.run_line_magic('timeit', '-n1 -r1 %lmagic my line')
     nt.assert_equal(_ip.user_ns['lmagic_out'], 'my line')
     # cell mode test
     _ip.run_cell_magic('timeit', '-n1 -r1', '%lmagic my line2')
     nt.assert_equal(_ip.user_ns['lmagic_out'], 'my line2')
 
 def test_timeit_return():
     """
     test whether timeit -o return object
     """
 
     res = _ip.run_line_magic('timeit','-n10 -r10 -o 1')
     assert(res is not None)
 
 def test_timeit_quiet():
     """
     test quiet option of timeit magic
     """
     with tt.AssertNotPrints("loops"):
         _ip.run_cell("%timeit -n1 -r1 -q 1")
 
 def test_timeit_return_quiet():
     with tt.AssertNotPrints("loops"):
         res = _ip.run_line_magic('timeit', '-n1 -r1 -q -o 1')
     assert (res is not None)
 
 def test_timeit_invalid_return():
     with nt.assert_raises_regex(SyntaxError, "outside function"):
         _ip.run_line_magic('timeit', 'return')
 
 @dec.skipif(execution.profile is None)
 def test_prun_special_syntax():
     "Test %%prun with IPython special syntax"
     @register_line_magic
     def lmagic(line):
         ip = get_ipython()
         ip.user_ns['lmagic_out'] = line
 
     # line mode test
     _ip.run_line_magic('prun', '-q %lmagic my line')
     nt.assert_equal(_ip.user_ns['lmagic_out'], 'my line')
     # cell mode test
     _ip.run_cell_magic('prun', '-q', '%lmagic my line2')
     nt.assert_equal(_ip.user_ns['lmagic_out'], 'my line2')
 
 @dec.skipif(execution.profile is None)
 def test_prun_quotes():
     "Test that prun does not clobber string escapes (GH #1302)"
     _ip.magic(r"prun -q x = '\t'")
     nt.assert_equal(_ip.user_ns['x'], '\t')
 
 def test_extension():
     # Debugging information for failures of this test
     print('sys.path:')
     for p in sys.path:
         print(' ', p)
     print('CWD', os.getcwd())
 
     nt.assert_raises(ImportError, _ip.magic, "load_ext daft_extension")
     daft_path = os.path.join(os.path.dirname(__file__), "daft_extension")
     sys.path.insert(0, daft_path)
     try:
         _ip.user_ns.pop('arq', None)
         invalidate_caches()   # Clear import caches
         _ip.magic("load_ext daft_extension")
         nt.assert_equal(_ip.user_ns['arq'], 185)
         _ip.magic("unload_ext daft_extension")
         assert 'arq' not in _ip.user_ns
     finally:
         sys.path.remove(daft_path)
 
 
 def test_notebook_export_json():
     _ip = get_ipython()
     _ip.history_manager.reset()   # Clear any existing history.
     cmds = [u"a=1", u"def b():\n  return a**2", u"print('noël, été', b())"]
     for i, cmd in enumerate(cmds, start=1):
         _ip.history_manager.store_inputs(i, cmd)
     with TemporaryDirectory() as td:
         outfile = os.path.join(td, "nb.ipynb")
         _ip.magic("notebook -e %s" % outfile)
 
 
 class TestEnv(TestCase):
 
     def test_env(self):
         env = _ip.magic("env")
         self.assertTrue(isinstance(env, dict))
 
     def test_env_secret(self):
         env = _ip.magic("env")
         hidden = "<hidden>"
         with mock.patch.dict(
             os.environ,
             {
                 "API_KEY": "abc123",
                 "SECRET_THING": "ssshhh",
                 "JUPYTER_TOKEN": "",
                 "VAR": "abc"
             }
         ):
             env = _ip.magic("env")
         assert env["API_KEY"] == hidden
         assert env["SECRET_THING"] == hidden
         assert env["JUPYTER_TOKEN"] == hidden
         assert env["VAR"] == "abc"
 
     def test_env_get_set_simple(self):
         env = _ip.magic("env var val1")
         self.assertEqual(env, None)
         self.assertEqual(os.environ['var'], 'val1')
         self.assertEqual(_ip.magic("env var"), 'val1')
         env = _ip.magic("env var=val2")
         self.assertEqual(env, None)
         self.assertEqual(os.environ['var'], 'val2')
 
     def test_env_get_set_complex(self):
         env = _ip.magic("env var 'val1 '' 'val2")
         self.assertEqual(env, None)
         self.assertEqual(os.environ['var'], "'val1 '' 'val2")
         self.assertEqual(_ip.magic("env var"), "'val1 '' 'val2")
         env = _ip.magic('env var=val2 val3="val4')
         self.assertEqual(env, None)
         self.assertEqual(os.environ['var'], 'val2 val3="val4')
 
     def test_env_set_bad_input(self):
         self.assertRaises(UsageError, lambda: _ip.magic("set_env var"))
 
     def test_env_set_whitespace(self):
         self.assertRaises(UsageError, lambda: _ip.magic("env var A=B"))
 
 
 class CellMagicTestCase(TestCase):
 
     def check_ident(self, magic):
         # Manually called, we get the result
         out = _ip.run_cell_magic(magic, 'a', 'b')
         nt.assert_equal(out, ('a','b'))
         # Via run_cell, it goes into the user's namespace via displayhook
         _ip.run_cell('%%' + magic +' c\nd\n')
         nt.assert_equal(_ip.user_ns['_'], ('c','d\n'))
 
     def test_cell_magic_func_deco(self):
         "Cell magic using simple decorator"
         @register_cell_magic
         def cellm(line, cell):
             return line, cell
 
         self.check_ident('cellm')
 
     def test_cell_magic_reg(self):
         "Cell magic manually registered"
         def cellm(line, cell):
             return line, cell
 
         _ip.register_magic_function(cellm, 'cell', 'cellm2')
         self.check_ident('cellm2')
 
     def test_cell_magic_class(self):
         "Cell magics declared via a class"
         @magics_class
         class MyMagics(Magics):
 
             @cell_magic
             def cellm3(self, line, cell):
                 return line, cell
 
         _ip.register_magics(MyMagics)
         self.check_ident('cellm3')
 
     def test_cell_magic_class2(self):
         "Cell magics declared via a class, #2"
         @magics_class
         class MyMagics2(Magics):
 
             @cell_magic('cellm4')
             def cellm33(self, line, cell):
                 return line, cell
             
         _ip.register_magics(MyMagics2)
         self.check_ident('cellm4')
         # Check that nothing is registered as 'cellm33'
         c33 = _ip.find_cell_magic('cellm33')
         nt.assert_equal(c33, None)
 
 def test_file():
     """Basic %%writefile"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, 'file1')
         ip.run_cell_magic("writefile", fname, u'\n'.join([
             'line1',
             'line2',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line2', s)
 
 @dec.skip_win32
 def test_file_single_quote():
     """Basic %%writefile with embedded single quotes"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, '\'file1\'')
         ip.run_cell_magic("writefile", fname, u'\n'.join([
             'line1',
             'line2',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line2', s)
 
 @dec.skip_win32
 def test_file_double_quote():
     """Basic %%writefile with embedded double quotes"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, '"file1"')
         ip.run_cell_magic("writefile", fname, u'\n'.join([
             'line1',
             'line2',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line2', s)
 
 def test_file_var_expand():
     """%%writefile $filename"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, 'file1')
         ip.user_ns['filename'] = fname
         ip.run_cell_magic("writefile", '$filename', u'\n'.join([
             'line1',
             'line2',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line2', s)
 
 def test_file_unicode():
     """%%writefile with unicode cell"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, 'file1')
         ip.run_cell_magic("writefile", fname, u'\n'.join([
             u'liné1',
             u'liné2',
         ]))
         with io.open(fname, encoding='utf-8') as f:
             s = f.read()
         nt.assert_in(u'liné1\n', s)
         nt.assert_in(u'liné2', s)
 
 def test_file_amend():
     """%%writefile -a amends files"""
     ip = get_ipython()
     with TemporaryDirectory() as td:
         fname = os.path.join(td, 'file2')
         ip.run_cell_magic("writefile", fname, u'\n'.join([
             'line1',
             'line2',
         ]))
         ip.run_cell_magic("writefile", "-a %s" % fname, u'\n'.join([
             'line3',
             'line4',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line3\n', s)
 
 def test_file_spaces():
     """%%file with spaces in filename"""
     ip = get_ipython()
     with TemporaryWorkingDirectory() as td:
         fname = "file name"
         ip.run_cell_magic("file", '"%s"'%fname, u'\n'.join([
             'line1',
             'line2',
         ]))
         s = Path(fname).read_text()
         nt.assert_in('line1\n', s)
         nt.assert_in('line2', s)
     
 def test_script_config():
     ip = get_ipython()
     ip.config.ScriptMagics.script_magics = ['whoda']
     sm = script.ScriptMagics(shell=ip)
     nt.assert_in('whoda', sm.magics['cell'])
 
 @dec.skip_win32
 def test_script_out():
     ip = get_ipython()
     ip.run_cell_magic("script", "--out output sh", "echo 'hi'")
     nt.assert_equal(ip.user_ns['output'], 'hi\n')
 
 @dec.skip_win32
 def test_script_err():
     ip = get_ipython()
     ip.run_cell_magic("script", "--err error sh", "echo 'hello' >&2")
     nt.assert_equal(ip.user_ns['error'], 'hello\n')
 
 @dec.skip_win32
 def test_script_out_err():
     ip = get_ipython()
     ip.run_cell_magic("script", "--out output --err error sh", "echo 'hi'\necho 'hello' >&2")
     nt.assert_equal(ip.user_ns['output'], 'hi\n')
     nt.assert_equal(ip.user_ns['error'], 'hello\n')
 
 @dec.skip_win32
 async def test_script_bg_out():
     ip = get_ipython()
     ip.run_cell_magic("script", "--bg --out output sh", "echo 'hi'")
     nt.assert_equal((await ip.user_ns["output"].read()), b"hi\n")
     ip.user_ns['output'].close()
 
 @dec.skip_win32
 async def test_script_bg_err():
     ip = get_ipython()
     ip.run_cell_magic("script", "--bg --err error sh", "echo 'hello' >&2")
     nt.assert_equal((await ip.user_ns["error"].read()), b"hello\n")
     ip.user_ns["error"].close()
 
 
 @dec.skip_win32
 async def test_script_bg_out_err():
     ip = get_ipython()
     ip.run_cell_magic(
         "script", "--bg --out output --err error sh", "echo 'hi'\necho 'hello' >&2"
     )
     nt.assert_equal((await ip.user_ns["output"].read()), b"hi\n")
     nt.assert_equal((await ip.user_ns["error"].read()), b"hello\n")
     ip.user_ns["output"].close()
     ip.user_ns["error"].close()
 
 
 def test_script_defaults():
     ip = get_ipython()
     for cmd in ['sh', 'bash', 'perl', 'ruby']:
         try:
             find_cmd(cmd)
         except Exception:
             pass
         else:
             nt.assert_in(cmd, ip.magics_manager.magics['cell'])
 
 
 @magics_class
 class FooFoo(Magics):
     """class with both %foo and %%foo magics"""
     @line_magic('foo')
     def line_foo(self, line):
         "I am line foo"
         pass
 
     @cell_magic("foo")
     def cell_foo(self, line, cell):
         "I am cell foo, not line foo"
         pass
 
 def test_line_cell_info():
     """%%foo and %foo magics are distinguishable to inspect"""
     ip = get_ipython()
     ip.magics_manager.register(FooFoo)
     oinfo = ip.object_inspect('foo')
     nt.assert_true(oinfo['found'])
     nt.assert_true(oinfo['ismagic'])
     
     oinfo = ip.object_inspect('%%foo')
     nt.assert_true(oinfo['found'])
     nt.assert_true(oinfo['ismagic'])
     nt.assert_equal(oinfo['docstring'], FooFoo.cell_foo.__doc__)
 
     oinfo = ip.object_inspect('%foo')
     nt.assert_true(oinfo['found'])
     nt.assert_true(oinfo['ismagic'])
     nt.assert_equal(oinfo['docstring'], FooFoo.line_foo.__doc__)
 
 def test_multiple_magics():
     ip = get_ipython()
     foo1 = FooFoo(ip)
     foo2 = FooFoo(ip)
     mm = ip.magics_manager
     mm.register(foo1)
     nt.assert_true(mm.magics['line']['foo'].__self__ is foo1)
     mm.register(foo2)
     nt.assert_true(mm.magics['line']['foo'].__self__ is foo2)
 
 def test_alias_magic():
     """Test %alias_magic."""
     ip = get_ipython()
     mm = ip.magics_manager
 
     # Basic operation: both cell and line magics are created, if possible.
     ip.run_line_magic('alias_magic', 'timeit_alias timeit')
     nt.assert_in('timeit_alias', mm.magics['line'])
     nt.assert_in('timeit_alias', mm.magics['cell'])
 
     # --cell is specified, line magic not created.
     ip.run_line_magic('alias_magic', '--cell timeit_cell_alias timeit')
     nt.assert_not_in('timeit_cell_alias', mm.magics['line'])
     nt.assert_in('timeit_cell_alias', mm.magics['cell'])
 
     # Test that line alias is created successfully.
     ip.run_line_magic('alias_magic', '--line env_alias env')
     nt.assert_equal(ip.run_line_magic('env', ''),
                     ip.run_line_magic('env_alias', ''))
 
     # Test that line alias with parameters passed in is created successfully.
     ip.run_line_magic('alias_magic', '--line history_alias history --params ' + shlex.quote('3'))
     nt.assert_in('history_alias', mm.magics['line'])
 
 
 def test_save():
     """Test %save."""
     ip = get_ipython()
     ip.history_manager.reset()   # Clear any existing history.
     cmds = [u"a=1", u"def b():\n  return a**2", u"print(a, b())"]
     for i, cmd in enumerate(cmds, start=1):
         ip.history_manager.store_inputs(i, cmd)
     with TemporaryDirectory() as tmpdir:
         file = os.path.join(tmpdir, "testsave.py")
         ip.run_line_magic("save", "%s 1-10" % file)
         content = Path(file).read_text()
         nt.assert_equal(content.count(cmds[0]), 1)
         nt.assert_in("coding: utf-8", content)
         ip.run_line_magic("save", "-a %s 1-10" % file)
         content = Path(file).read_text()
         nt.assert_equal(content.count(cmds[0]), 2)
         nt.assert_in("coding: utf-8", content)
 
 
+def test_save_with_no_args():
+    ip = get_ipython()
+    ip.history_manager.reset()  # Clear any existing history.
+    cmds = [u"a=1", u"def b():\n    return a**2", u"print(a, b())", "%save"]
+    for i, cmd in enumerate(cmds, start=1):
+        ip.history_manager.store_inputs(i, cmd)
+
+    with TemporaryDirectory() as tmpdir:
+        path = os.path.join(tmpdir, "testsave.py")
+        ip.run_line_magic("save", path)
+        content = Path(path).read_text()
+        expected_content = dedent(
+            """\
+            # coding: utf-8
+            a=1
+            def b():
+                return a**2
+            print(a, b())
+            """
+        )
+        nt.assert_equal(content, expected_content)
+
+
 def test_store():
     """Test %store."""
     ip = get_ipython()
     ip.run_line_magic('load_ext', 'storemagic')
     
     # make sure the storage is empty
     ip.run_line_magic('store', '-z')
     ip.user_ns['var'] = 42
     ip.run_line_magic('store', 'var')
     ip.user_ns['var'] = 39
     ip.run_line_magic('store', '-r')
     nt.assert_equal(ip.user_ns['var'], 42)
 
     ip.run_line_magic('store', '-d var')
     ip.user_ns['var'] = 39
     ip.run_line_magic('store' , '-r')
     nt.assert_equal(ip.user_ns['var'], 39)
 
 
 def _run_edit_test(arg_s, exp_filename=None,
                         exp_lineno=-1,
                         exp_contents=None,
                         exp_is_temp=None):
     ip = get_ipython()
     M = code.CodeMagics(ip)
     last_call = ['','']
     opts,args = M.parse_options(arg_s,'prxn:')
     filename, lineno, is_temp = M._find_edit_target(ip, args, opts, last_call)
         
     if exp_filename is not None:
         nt.assert_equal(exp_filename, filename)
     if exp_contents is not None:
         with io.open(filename, 'r', encoding='utf-8') as f:
             contents = f.read()
         nt.assert_equal(exp_contents, contents)
     if exp_lineno != -1:
         nt.assert_equal(exp_lineno, lineno)
     if exp_is_temp is not None:
         nt.assert_equal(exp_is_temp, is_temp)
 
 
 def test_edit_interactive():
     """%edit on interactively defined objects"""
     ip = get_ipython()
     n = ip.execution_count
     ip.run_cell(u"def foo(): return 1", store_history=True)
     
     try:
         _run_edit_test("foo")
     except code.InteractivelyDefined as e:
         nt.assert_equal(e.index, n)
     else:
         raise AssertionError("Should have raised InteractivelyDefined")
 
 
 def test_edit_cell():
     """%edit [cell id]"""
     ip = get_ipython()
     
     ip.run_cell(u"def foo(): return 1", store_history=True)
     
     # test
     _run_edit_test("1", exp_contents=ip.user_ns['In'][1], exp_is_temp=True)
 
 def test_edit_fname():
     """%edit file"""
     # test
     _run_edit_test("test file.py", exp_filename="test file.py")
 
 def test_bookmark():
     ip = get_ipython()
     ip.run_line_magic('bookmark', 'bmname')
     with tt.AssertPrints('bmname'):
         ip.run_line_magic('bookmark', '-l')
     ip.run_line_magic('bookmark', '-d bmname')
 
 def test_ls_magic():
     ip = get_ipython()
     json_formatter = ip.display_formatter.formatters['application/json']
     json_formatter.enabled = True
     lsmagic = ip.magic('lsmagic')
     with warnings.catch_warnings(record=True) as w:
         j = json_formatter(lsmagic)
     nt.assert_equal(sorted(j), ['cell', 'line'])
     nt.assert_equal(w, []) # no warnings
 
 def test_strip_initial_indent():
     def sii(s):
         lines = s.splitlines()
         return '\n'.join(code.strip_initial_indent(lines))
 
     nt.assert_equal(sii("  a = 1\nb = 2"), "a = 1\nb = 2")
     nt.assert_equal(sii("  a\n    b\nc"), "a\n  b\nc")
     nt.assert_equal(sii("a\n  b"), "a\n  b")
 
 def test_logging_magic_quiet_from_arg():
     _ip.config.LoggingMagics.quiet = False
     lm = logging.LoggingMagics(shell=_ip)
     with TemporaryDirectory() as td:
         try:
             with tt.AssertNotPrints(re.compile("Activating.*")):
                 lm.logstart('-q {}'.format(
                         os.path.join(td, "quiet_from_arg.log")))
         finally:
             _ip.logger.logstop()
 
 def test_logging_magic_quiet_from_config():
     _ip.config.LoggingMagics.quiet = True
     lm = logging.LoggingMagics(shell=_ip)
     with TemporaryDirectory() as td:
         try:
             with tt.AssertNotPrints(re.compile("Activating.*")):
                 lm.logstart(os.path.join(td, "quiet_from_config.log"))
         finally:
             _ip.logger.logstop()
 
 
 def test_logging_magic_not_quiet():
     _ip.config.LoggingMagics.quiet = False
     lm = logging.LoggingMagics(shell=_ip)
     with TemporaryDirectory() as td:
         try:
             with tt.AssertPrints(re.compile("Activating.*")):
                 lm.logstart(os.path.join(td, "not_quiet.log"))
         finally:
             _ip.logger.logstop()
 
 
 def test_time_no_var_expand():
     _ip.user_ns['a'] = 5
     _ip.user_ns['b'] = []
     _ip.magic('time b.append("{a}")')
     assert _ip.user_ns['b'] == ['{a}']
 
 
 # this is slow, put at the end for local testing.
 def test_timeit_arguments():
     "Test valid timeit arguments, should not cause SyntaxError (GH #1269)"
     if sys.version_info < (3,7):
         _ip.magic("timeit -n1 -r1 ('#')")
     else:
         # 3.7 optimize no-op statement like above out, and complain there is
         # nothing in the for loop.
         _ip.magic("timeit -n1 -r1 a=('#')")
 
 
 TEST_MODULE = """
 print('Loaded my_tmp')
 if __name__ == "__main__":
     print('I just ran a script')
 """
 
 
 def test_run_module_from_import_hook():
     "Test that a module can be loaded via an import hook"
     with TemporaryDirectory() as tmpdir:
         fullpath = os.path.join(tmpdir, 'my_tmp.py')
         Path(fullpath).write_text(TEST_MODULE)
 
         class MyTempImporter(object):
             def __init__(self):
                 pass
 
             def find_module(self, fullname, path=None):
                 if 'my_tmp' in fullname:
                     return self
                 return None
 
             def load_module(self, name):
                 import imp
                 return imp.load_source('my_tmp', fullpath)
 
             def get_code(self, fullname):
                 return compile(Path(fullpath).read_text(), "foo", "exec")
 
             def is_package(self, __):
                 return False
 
         sys.meta_path.insert(0, MyTempImporter())
 
         with capture_output() as captured:
             _ip.magic("run -m my_tmp")
             _ip.run_cell("import my_tmp")
 
         output = "Loaded my_tmp\nI just ran a script\nLoaded my_tmp\n"
         nt.assert_equal(output, captured.stdout)
 
         sys.meta_path.pop(0)