upstream/ipython Files · IPython/utils/ulinecache.py

Reset the interactive namespace __warningregistry__ before executing code...

Reset the interactive namespace __warningregistry__ before executing code Fixes . Idea: Right now, people often don't see important warnings when running code in IPython, because (to a first approximation) any given warning will only issue once per session. Blink and you'll miss it! This is a very common contributor to confused emails to numpy-discussion. E.g.: In [5]: 1 / my_array_with_random_contents /home/njs/.user-python2.7-64bit-3/bin/ipython:1: RuntimeWarning: divide by zero encountered in divide #!/home/njs/.user-python2.7-64bit-3/bin/python Out[5]: array([ 1.77073316, -2.29765021, -2.01800811, ..., 1.13871243, -1.08302964, -8.6185091 ]) Oo, right, guess I gotta be careful of those zeros -- thanks, numpy, for giving me that warning! A few days later: In [592]: 1 / some_other_array Out[592]: array([ 3.07735763, 0.50769289, 0.83984078, ..., -0.67563917, -0.85736257, -1.36511271]) Oops, it turns out that this array had a zero in it too, and that's going to bite me later. But no warning this time! The effect of this commit is to make it so that warnings triggered by the code in cell 5 do *not* suppress warnings triggered by the code in cell 592. Note that this only applies to warnings triggered *directly* by code entered interactively -- if somepkg.foo() calls anotherpkg.bad_func() which issues a warning, then this warning will still only be displayed once, even if multiple cells call somepkg.foo(). But if cell 5 and cell 592 both call anotherpkg.bad_func() directly, then both will get warnings. (Important exception: if foo() is defined *interactively*, and calls anotherpkg.bad_func(), then every cell that calls foo() will display the warning again. This is unavoidable without fixes to CPython upstream.) Explanation: Python's warning system has some weird quirks. By default, it tries to suppress duplicate warnings, where "duplicate" means the same warning message triggered twice by the same line of code. This requires determining which line of code is responsible for triggering a warning, and this is controlled by the stacklevel= argument to warnings.warn. Basically, though, the idea is that if foo() calls bar() which calls baz() which calls some_deprecated_api(), then baz() will get counted as being "responsible", and the warning system will make a note that the usage of some_deprecated_api() inside baz() has already been warned about and doesn't need to be warned about again. So far so good. To accomplish this, obviously, there has to be a record of somewhere which line this was. You might think that this would be done by recording the filename:linenumber pair in a dict inside the warnings module, or something like that. You would be wrong. What actually happens is that the warnings module will use stack introspection to reach into baz()'s execution environment, create a global (module-level) variable there named __warningregistry__, and then, inside this dictionary, record just the line number. Basically, it assumes that any given module contains only one line 1, only one line 2, etc., so storing the filename is irrelevant. Obviously for interactive code this is totally wrong -- all cells share the same execution environment and global namespace, and they all contain a new line 1. Currently the warnings module treats these as if they were all the same line. In fact they are not the same line; once we have executed a given chunk of code, we will never see those particular lines again. As soon as a given chunk of code finishes executing, its line number labels become meaningless, and the corresponding warning registry entries become meaningless as well. Therefore, with this patch we delete the __warningregistry__ each time we execute a new block of code.

Thomas Kluyver - - Load All Authors

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        Thomas Kluyver
    
Fix getting unicode lines in IPython.core.debugger.

              r8324
            
      """Wrapper around linecache which decodes files to unicode according to PEP 263.

      This is only needed for Python 2 - linecache in Python 3 does the same thing

      itself.

      """

      import functools

      import linecache

        Jörgen Stenarson
    
Convert filename to bytes in getlines....

              r8335
            
      import sys

        Thomas Kluyver
    
Fix getting unicode lines in IPython.core.debugger.

              r8324
            
      from IPython.utils import py3compat

      from IPython.utils import openpy

      if py3compat.PY3:

          getline = linecache.getline

          # getlines has to be looked up at runtime, because doctests monkeypatch it.

          @functools.wraps(linecache.getlines)

          def getlines(filename, module_globals=None):

              return linecache.getlines(filename, module_globals=module_globals)

      else:

          def getlines(filename, module_globals=None):

              """Get the lines (as unicode) for a file from the cache.

              Update the cache if it doesn't contain an entry for this file already."""

        Jörgen Stenarson
    
Convert filename to bytes in getlines....

              r8335
            
              filename = py3compat.cast_bytes(filename, sys.getfilesystemencoding())

        Thomas Kluyver
    
Fixes for producing unicode tracebacks.

              r8325
            
              lines = linecache.getlines(filename, module_globals=module_globals)

              # The bits we cache ourselves can be unicode.

        Thomas Kluyver
    
Replace references to unicode and basestring

              r13353
            
              if (not lines) or isinstance(lines[0], py3compat.unicode_type):

        Thomas Kluyver
    
Fixes for producing unicode tracebacks.

              r8325
            
                  return lines

              readline = openpy._list_readline(lines)

        Thomas Kluyver
    
Fix getting unicode lines in IPython.core.debugger.

              r8324
            
              try:

                  encoding, _ = openpy.detect_encoding(readline)

              except SyntaxError:

                  encoding = 'ascii'

        Thomas Kluyver
    
Fixes for producing unicode tracebacks.

              r8325
            
              return [l.decode(encoding, 'replace') for l in lines]

        Thomas Kluyver
    
Fix getting unicode lines in IPython.core.debugger.

              r8324
            
          # This is a straight copy of linecache.getline

          def getline(filename, lineno, module_globals=None):

              lines = getlines(filename, module_globals)

              if 1 <= lineno <= len(lines):

                  return lines[lineno-1]

              else:

                  return ''

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Thomas Kluyver Fix getting unicode lines in IPython.core.debugger.	r8324	"""Wrapper around linecache which decodes files to unicode according to PEP 263.

		This is only needed for Python 2 - linecache in Python 3 does the same thing
		itself.
		"""
		import functools
		import linecache
Jörgen Stenarson Convert filename to bytes in getlines....	r8335	import sys
Thomas Kluyver Fix getting unicode lines in IPython.core.debugger.	r8324
		from IPython.utils import py3compat
		from IPython.utils import openpy

		if py3compat.PY3:
		getline = linecache.getline

		# getlines has to be looked up at runtime, because doctests monkeypatch it.
		@functools.wraps(linecache.getlines)
		def getlines(filename, module_globals=None):
		return linecache.getlines(filename, module_globals=module_globals)

		else:
		def getlines(filename, module_globals=None):
		"""Get the lines (as unicode) for a file from the cache.
		Update the cache if it doesn't contain an entry for this file already."""
Jörgen Stenarson Convert filename to bytes in getlines....	r8335	filename = py3compat.cast_bytes(filename, sys.getfilesystemencoding())
Thomas Kluyver Fixes for producing unicode tracebacks.	r8325	lines = linecache.getlines(filename, module_globals=module_globals)

		# The bits we cache ourselves can be unicode.
Thomas Kluyver Replace references to unicode and basestring	r13353	if (not lines) or isinstance(lines[0], py3compat.unicode_type):
Thomas Kluyver Fixes for producing unicode tracebacks.	r8325	return lines

		readline = openpy._list_readline(lines)
Thomas Kluyver Fix getting unicode lines in IPython.core.debugger.	r8324	try:
		encoding, _ = openpy.detect_encoding(readline)
		except SyntaxError:
		encoding = 'ascii'
Thomas Kluyver Fixes for producing unicode tracebacks.	r8325	return [l.decode(encoding, 'replace') for l in lines]
Thomas Kluyver Fix getting unicode lines in IPython.core.debugger.	r8324
		# This is a straight copy of linecache.getline
		def getline(filename, lineno, module_globals=None):
		lines = getlines(filename, module_globals)
		if 1 <= lineno <= len(lines):
		return lines[lineno-1]
		else:
		return ''