upstream/ipython Files · IPython/core/tests/tclass.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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        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
      """Simple script to be run *twice*, to check reference counting bugs.

        Fernando Perez
    
Cleanup testing machinery.

              r1851
            
        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
      See test_run for details."""

        Fernando Perez
    
Cleanup testing machinery.

              r1851
            
        Thomas Kluyver
    
Start using py3compat module.

              r4731
            
      from __future__ import print_function

        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
      import sys

        Fernando Perez
    
Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...

              r1856
            
        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
      # We want to ensure that while objects remain available for immediate access,

      # objects from *previous* runs of the same script get collected, to avoid

      # accumulating massive amounts of old references.

        Fernando Perez
    
Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...

              r1856
            
      class C(object):

          def __init__(self,name):

              self.name = name

        Thomas Kluyver
    
Start using py3compat module.

              r4731
            
              self.p = print

        Thomas Kluyver
    
Shell's reset method clears namespace from last %run command.

              r3762
            
              self.flush_stdout = sys.stdout.flush

        Fernando Perez
    
Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...

              r1856
            
          def __del__(self):

        Thomas Kluyver
    
Start using py3compat module.

              r4731
            
              self.p('tclass.py: deleting object:',self.name)

        Thomas Kluyver
    
Shell's reset method clears namespace from last %run command.

              r3762
            
              self.flush_stdout()

        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
        Fernando Perez
    
Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...

              r1856
            
      try:

          name = sys.argv[1]

      except IndexError:

          pass

      else:

        Fernando Perez
    
- Make ipdoctest a little cleaner by giving it separate option names....

              r1910
            
          if name.startswith('C'):

              c = C(name)

        Fernando Perez
    
Massive amount of work to improve the test suite, restores doctests....

              r2414
            
      #print >> sys.stderr, "ARGV:", sys.argv  # dbg

        Fernando Perez
    
Fix extensions test suite (small, but now it runs and passes!)

              r2415
            
      # This next print statement is NOT debugging, we're making the check on a

      # completely separate process so we verify by capturing stdout:

        Thomas Kluyver
    
Repair various failures in the test suite.

              r4734
            
      print('ARGV 1-:', sys.argv[1:])

        Fernando Perez
    
Robustness fixes in test suite machinery....

              r2494
            
      sys.stdout.flush()

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Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414	"""Simple script to be run twice, to check reference counting bugs.
Fernando Perez Cleanup testing machinery.	r1851
Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414	See test_run for details."""
Fernando Perez Cleanup testing machinery.	r1851
Thomas Kluyver Start using py3compat module.	r4731	from __future__ import print_function

Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414	import sys
Fernando Perez Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...	r1856
Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414	# We want to ensure that while objects remain available for immediate access,
		# objects from previous runs of the same script get collected, to avoid
		# accumulating massive amounts of old references.
Fernando Perez Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...	r1856	class C(object):
		def __init__(self,name):
		self.name = name
Thomas Kluyver Start using py3compat module.	r4731	self.p = print
Thomas Kluyver Shell's reset method clears namespace from last %run command.	r3762	self.flush_stdout = sys.stdout.flush
Fernando Perez Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...	r1856
		def __del__(self):
Thomas Kluyver Start using py3compat module.	r4731	self.p('tclass.py: deleting object:',self.name)
Thomas Kluyver Shell's reset method clears namespace from last %run command.	r3762	self.flush_stdout()
Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414
Fernando Perez Fix bug: https://bugs.launchpad.net/ipython/+bug/269966...	r1856	try:
		name = sys.argv[1]
		except IndexError:
		pass
		else:
Fernando Perez - Make ipdoctest a little cleaner by giving it separate option names....	r1910	if name.startswith('C'):
		c = C(name)
Fernando Perez Massive amount of work to improve the test suite, restores doctests....	r2414
		#print >> sys.stderr, "ARGV:", sys.argv # dbg
Fernando Perez Fix extensions test suite (small, but now it runs and passes!)	r2415
		# This next print statement is NOT debugging, we're making the check on a
		# completely separate process so we verify by capturing stdout:
Thomas Kluyver Repair various failures in the test suite.	r4734	print('ARGV 1-:', sys.argv[1:])
Fernando Perez Robustness fixes in test suite machinery....	r2494	sys.stdout.flush()