Skip scanning for module names with no global shell instance

Closes gh-9798

IPython/core/completerlib.py

@@ -1,342 +1,347 b''
 # encoding: utf-8
 """Implementations for various useful completers.
 
 These are all loaded by default by IPython.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011 The IPython Development Team.
 #
 #  Distributed under the terms of the BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib imports
 import glob
 import inspect
 import os
 import re
 import sys
 from importlib import import_module
 from importlib.machinery import all_suffixes
 
 
 # Third-party imports
 from time import time
 from zipimport import zipimporter
 
 # Our own imports
 from IPython.core.completer import expand_user, compress_user
 from IPython.core.error import TryNext
 from IPython.utils._process_common import arg_split
 
 # FIXME: this should be pulled in with the right call via the component system
 from IPython import get_ipython
 
 #-----------------------------------------------------------------------------
 # Globals and constants
 #-----------------------------------------------------------------------------
 _suffixes = all_suffixes()
 
 # Time in seconds after which the rootmodules will be stored permanently in the
 # ipython ip.db database (kept in the user's .ipython dir).
 TIMEOUT_STORAGE = 2
 
 # Time in seconds after which we give up
 TIMEOUT_GIVEUP = 20
 
 # Regular expression for the python import statement
 import_re = re.compile(r'(?P<name>[a-zA-Z_][a-zA-Z0-9_]*?)'
                        r'(?P<package>[/\\]__init__)?'
                        r'(?P<suffix>%s)$' %
                        r'|'.join(re.escape(s) for s in _suffixes))
 
 # RE for the ipython %run command (python + ipython scripts)
 magic_run_re = re.compile(r'.*(\.ipy|\.ipynb|\.py[w]?)$')
 
 #-----------------------------------------------------------------------------
 # Local utilities
 #-----------------------------------------------------------------------------
 
 def module_list(path):
     """
     Return the list containing the names of the modules available in the given
     folder.
     """
     # sys.path has the cwd as an empty string, but isdir/listdir need it as '.'
     if path == '':
         path = '.'
 
     # A few local constants to be used in loops below
     pjoin = os.path.join
 
     if os.path.isdir(path):
         # Build a list of all files in the directory and all files
         # in its subdirectories. For performance reasons, do not
         # recurse more than one level into subdirectories.
         files = []
         for root, dirs, nondirs in os.walk(path, followlinks=True):
             subdir = root[len(path)+1:]
             if subdir:
                 files.extend(pjoin(subdir, f) for f in nondirs)
                 dirs[:] = [] # Do not recurse into additional subdirectories.
             else:
                 files.extend(nondirs)
 
     else:
         try:
             files = list(zipimporter(path)._files.keys())
         except:
             files = []
 
     # Build a list of modules which match the import_re regex.
     modules = []
     for f in files:
         m = import_re.match(f)
         if m:
             modules.append(m.group('name'))
     return list(set(modules))
 
 
 def get_root_modules():
     """
     Returns a list containing the names of all the modules available in the
     folders of the pythonpath.
 
     ip.db['rootmodules_cache'] maps sys.path entries to list of modules.
     """
     ip = get_ipython()
+    if ip is None:
+        # No global shell instance to store cached list of modules.
+        # Don't try to scan for modules every time.
+        return list(sys.builtin_module_names)
+
     rootmodules_cache = ip.db.get('rootmodules_cache', {})
     rootmodules = list(sys.builtin_module_names)
     start_time = time()
     store = False
     for path in sys.path:
         try:
             modules = rootmodules_cache[path]
         except KeyError:
             modules = module_list(path)
             try:
                 modules.remove('__init__')
             except ValueError:
                 pass
             if path not in ('', '.'): # cwd modules should not be cached
                 rootmodules_cache[path] = modules
             if time() - start_time > TIMEOUT_STORAGE and not store:
                 store = True
                 print("\nCaching the list of root modules, please wait!")
                 print("(This will only be done once - type '%rehashx' to "
                       "reset cache!)\n")
                 sys.stdout.flush()
             if time() - start_time > TIMEOUT_GIVEUP:
                 print("This is taking too long, we give up.\n")
                 return []
         rootmodules.extend(modules)
     if store:
         ip.db['rootmodules_cache'] = rootmodules_cache
     rootmodules = list(set(rootmodules))
     return rootmodules
 
 
 def is_importable(module, attr, only_modules):
     if only_modules:
         return inspect.ismodule(getattr(module, attr))
     else:
         return not(attr[:2] == '__' and attr[-2:] == '__')
 
 def try_import(mod, only_modules=False):
     try:
         m = import_module(mod)
     except:
         return []
 
     m_is_init = hasattr(m, '__file__') and '__init__' in m.__file__
 
     completions = []
     if (not hasattr(m, '__file__')) or (not only_modules) or m_is_init:
         completions.extend( [attr for attr in dir(m) if
                              is_importable(m, attr, only_modules)])
 
     completions.extend(getattr(m, '__all__', []))
     if m_is_init:
         completions.extend(module_list(os.path.dirname(m.__file__)))
     completions = {c for c in completions if isinstance(c, str)}
     completions.discard('__init__')
     return list(completions)
 
 
 #-----------------------------------------------------------------------------
 # Completion-related functions.
 #-----------------------------------------------------------------------------
 
 def quick_completer(cmd, completions):
     """ Easily create a trivial completer for a command.
 
     Takes either a list of completions, or all completions in string (that will
     be split on whitespace).
 
     Example::
 
         [d:\ipython]|1> import ipy_completers
         [d:\ipython]|2> ipy_completers.quick_completer('foo', ['bar','baz'])
         [d:\ipython]|3> foo b<TAB>
         bar baz
         [d:\ipython]|3> foo ba
     """
 
     if isinstance(completions, str):
         completions = completions.split()
 
     def do_complete(self, event):
         return completions
 
     get_ipython().set_hook('complete_command',do_complete, str_key = cmd)
 
 def module_completion(line):
     """
     Returns a list containing the completion possibilities for an import line.
 
     The line looks like this :
     'import xml.d'
     'from xml.dom import'
     """
 
     words = line.split(' ')
     nwords = len(words)
 
     # from whatever <tab> -> 'import '
     if nwords == 3 and words[0] == 'from':
         return ['import ']
 
     # 'from xy<tab>' or 'import xy<tab>'
     if nwords < 3 and (words[0] in {'%aimport', 'import', 'from'}) :
         if nwords == 1:
             return get_root_modules()
         mod = words[1].split('.')
         if len(mod) < 2:
             return get_root_modules()
         completion_list = try_import('.'.join(mod[:-1]), True)
         return ['.'.join(mod[:-1] + [el]) for el in completion_list]
 
     # 'from xyz import abc<tab>'
     if nwords >= 3 and words[0] == 'from':
         mod = words[1]
         return try_import(mod)
 
 #-----------------------------------------------------------------------------
 # Completers
 #-----------------------------------------------------------------------------
 # These all have the func(self, event) signature to be used as custom
 # completers
 
 def module_completer(self,event):
     """Give completions after user has typed 'import ...' or 'from ...'"""
 
     # This works in all versions of python.  While 2.5 has
     # pkgutil.walk_packages(), that particular routine is fairly dangerous,
     # since it imports *EVERYTHING* on sys.path.  That is: a) very slow b) full
     # of possibly problematic side effects.
     # This search the folders in the sys.path for available modules.
 
     return module_completion(event.line)
 
 # FIXME: there's a lot of logic common to the run, cd and builtin file
 # completers, that is currently reimplemented in each.
 
 def magic_run_completer(self, event):
     """Complete files that end in .py or .ipy or .ipynb for the %run command.
     """
     comps = arg_split(event.line, strict=False)
     # relpath should be the current token that we need to complete.
     if (len(comps) > 1) and (not event.line.endswith(' ')):
         relpath = comps[-1].strip("'\"")
     else:
         relpath = ''
 
     #print("\nev=", event)  # dbg
     #print("rp=", relpath)  # dbg
     #print('comps=', comps)  # dbg
 
     lglob = glob.glob
     isdir = os.path.isdir
     relpath, tilde_expand, tilde_val = expand_user(relpath)
 
     # Find if the user has already typed the first filename, after which we
     # should complete on all files, since after the first one other files may
     # be arguments to the input script.
 
     if any(magic_run_re.match(c) for c in comps):
         matches =  [f.replace('\\','/') + ('/' if isdir(f) else '')
                             for f in lglob(relpath+'*')]
     else:
         dirs = [f.replace('\\','/') + "/" for f in lglob(relpath+'*') if isdir(f)]
         pys =  [f.replace('\\','/')
                 for f in lglob(relpath+'*.py') + lglob(relpath+'*.ipy') +
                 lglob(relpath+'*.ipynb') + lglob(relpath + '*.pyw')]
 
         matches = dirs + pys
 
     #print('run comp:', dirs+pys) # dbg
     return [compress_user(p, tilde_expand, tilde_val) for p in matches]
 
 
 def cd_completer(self, event):
     """Completer function for cd, which only returns directories."""
     ip = get_ipython()
     relpath = event.symbol
 
     #print(event) # dbg
     if event.line.endswith('-b') or ' -b ' in event.line:
         # return only bookmark completions
         bkms = self.db.get('bookmarks', None)
         if bkms:
             return bkms.keys()
         else:
             return []
 
     if event.symbol == '-':
         width_dh = str(len(str(len(ip.user_ns['_dh']) + 1)))
         # jump in directory history by number
         fmt = '-%0' + width_dh +'d [%s]'
         ents = [ fmt % (i,s) for i,s in enumerate(ip.user_ns['_dh'])]
         if len(ents) > 1:
             return ents
         return []
 
     if event.symbol.startswith('--'):
         return ["--" + os.path.basename(d) for d in ip.user_ns['_dh']]
 
     # Expand ~ in path and normalize directory separators.
     relpath, tilde_expand, tilde_val = expand_user(relpath)
     relpath = relpath.replace('\\','/')
 
     found = []
     for d in [f.replace('\\','/') + '/' for f in glob.glob(relpath+'*')
               if os.path.isdir(f)]:
         if ' ' in d:
             # we don't want to deal with any of that, complex code
             # for this is elsewhere
             raise TryNext
 
         found.append(d)
 
     if not found:
         if os.path.isdir(relpath):
             return [compress_user(relpath, tilde_expand, tilde_val)]
 
         # if no completions so far, try bookmarks
         bks = self.db.get('bookmarks',{})
         bkmatches = [s for s in bks if s.startswith(event.symbol)]
         if bkmatches:
             return bkmatches
 
         raise TryNext
 
     return [compress_user(p, tilde_expand, tilde_val) for p in found]
 
 def reset_completer(self, event):
     "A completer for %reset magic"
     return '-f -s in out array dhist'.split()