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Reset the interactive namespace __warningregistry__ before executing code...
Reset the interactive namespace __warningregistry__ before executing code Fixes #6611. 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.

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nbbase.py
200 lines | 6.3 KiB | text/x-python | PythonLexer
"""The basic dict based notebook format.
The Python representation of a notebook is a nested structure of
dictionary subclasses that support attribute access
(IPython.utils.ipstruct.Struct). The functions in this module are merely
helpers to build the structs in the right form.
"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import pprint
import uuid
from IPython.utils.ipstruct import Struct
from IPython.utils.py3compat import cast_unicode, unicode_type
#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------
# Change this when incrementing the nbformat version
nbformat = 3
nbformat_minor = 0
nbformat_schema = 'nbformat.v3.schema.json'
class NotebookNode(Struct):
pass
def from_dict(d):
if isinstance(d, dict):
newd = NotebookNode()
for k,v in d.items():
newd[k] = from_dict(v)
return newd
elif isinstance(d, (tuple, list)):
return [from_dict(i) for i in d]
else:
return d
def new_output(output_type, output_text=None, output_png=None,
output_html=None, output_svg=None, output_latex=None, output_json=None,
output_javascript=None, output_jpeg=None, prompt_number=None,
ename=None, evalue=None, traceback=None, stream=None, metadata=None):
"""Create a new output, to go in the ``cell.outputs`` list of a code cell.
"""
output = NotebookNode()
output.output_type = unicode_type(output_type)
if metadata is None:
metadata = {}
if not isinstance(metadata, dict):
raise TypeError("metadata must be dict")
if output_type != 'pyerr':
if output_text is not None:
output.text = cast_unicode(output_text)
if output_png is not None:
output.png = cast_unicode(output_png)
if output_jpeg is not None:
output.jpeg = cast_unicode(output_jpeg)
if output_html is not None:
output.html = cast_unicode(output_html)
if output_svg is not None:
output.svg = cast_unicode(output_svg)
if output_latex is not None:
output.latex = cast_unicode(output_latex)
if output_json is not None:
output.json = cast_unicode(output_json)
if output_javascript is not None:
output.javascript = cast_unicode(output_javascript)
if output_type == u'pyout':
if prompt_number is not None:
output.prompt_number = int(prompt_number)
if output_type == u'pyerr':
if ename is not None:
output.ename = cast_unicode(ename)
if evalue is not None:
output.evalue = cast_unicode(evalue)
if traceback is not None:
output.traceback = [cast_unicode(frame) for frame in list(traceback)]
if output_type == u'stream':
output.stream = 'stdout' if stream is None else cast_unicode(stream)
else:
output.metadata = metadata
return output
def new_code_cell(input=None, prompt_number=None, outputs=None,
language=u'python', collapsed=False, metadata=None):
"""Create a new code cell with input and output"""
cell = NotebookNode()
cell.cell_type = u'code'
if language is not None:
cell.language = cast_unicode(language)
if input is not None:
cell.input = cast_unicode(input)
if prompt_number is not None:
cell.prompt_number = int(prompt_number)
if outputs is None:
cell.outputs = []
else:
cell.outputs = outputs
if collapsed is not None:
cell.collapsed = bool(collapsed)
cell.metadata = NotebookNode(metadata or {})
return cell
def new_text_cell(cell_type, source=None, rendered=None, metadata=None):
"""Create a new text cell."""
cell = NotebookNode()
# VERSIONHACK: plaintext -> raw
# handle never-released plaintext name for raw cells
if cell_type == 'plaintext':
cell_type = 'raw'
if source is not None:
cell.source = cast_unicode(source)
cell.metadata = NotebookNode(metadata or {})
cell.cell_type = cell_type
return cell
def new_heading_cell(source=None, level=1, rendered=None, metadata=None):
"""Create a new section cell with a given integer level."""
cell = NotebookNode()
cell.cell_type = u'heading'
if source is not None:
cell.source = cast_unicode(source)
cell.level = int(level)
cell.metadata = NotebookNode(metadata or {})
return cell
def new_worksheet(name=None, cells=None, metadata=None):
"""Create a worksheet by name with with a list of cells."""
ws = NotebookNode()
if cells is None:
ws.cells = []
else:
ws.cells = list(cells)
ws.metadata = NotebookNode(metadata or {})
return ws
def new_notebook(name=None, metadata=None, worksheets=None):
"""Create a notebook by name, id and a list of worksheets."""
nb = NotebookNode()
nb.nbformat = nbformat
nb.nbformat_minor = nbformat_minor
if worksheets is None:
nb.worksheets = []
else:
nb.worksheets = list(worksheets)
if metadata is None:
nb.metadata = new_metadata()
else:
nb.metadata = NotebookNode(metadata)
if name is not None:
nb.metadata.name = cast_unicode(name)
return nb
def new_metadata(name=None, authors=None, license=None, created=None,
modified=None, gistid=None):
"""Create a new metadata node."""
metadata = NotebookNode()
if name is not None:
metadata.name = cast_unicode(name)
if authors is not None:
metadata.authors = list(authors)
if created is not None:
metadata.created = cast_unicode(created)
if modified is not None:
metadata.modified = cast_unicode(modified)
if license is not None:
metadata.license = cast_unicode(license)
if gistid is not None:
metadata.gistid = cast_unicode(gistid)
return metadata
def new_author(name=None, email=None, affiliation=None, url=None):
"""Create a new author."""
author = NotebookNode()
if name is not None:
author.name = cast_unicode(name)
if email is not None:
author.email = cast_unicode(email)
if affiliation is not None:
author.affiliation = cast_unicode(affiliation)
if url is not None:
author.url = cast_unicode(url)
return author