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672237dc6c
WarningsRecorder object. This makes the API simpler to use as no special object must be learned. Closes issue 3781. Review by Benjamin Peterson.
387 lines
13 KiB
Python
387 lines
13 KiB
Python
"""Python part of the warnings subsystem."""
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# Note: function level imports should *not* be used
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# in this module as it may cause import lock deadlock.
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# See bug 683658.
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import linecache
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import sys
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import types
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__all__ = ["warn", "showwarning", "formatwarning", "filterwarnings",
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"resetwarnings", "catch_warnings"]
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def warnpy3k(message, category=None, stacklevel=1):
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"""Issue a deprecation warning for Python 3.x related changes.
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Warnings are omitted unless Python is started with the -3 option.
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"""
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if sys.py3kwarning:
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if category is None:
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category = DeprecationWarning
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warn(message, category, stacklevel+1)
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def _show_warning(message, category, filename, lineno, file=None, line=None):
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"""Hook to write a warning to a file; replace if you like."""
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if file is None:
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file = sys.stderr
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try:
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file.write(formatwarning(message, category, filename, lineno, line))
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except IOError:
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pass # the file (probably stderr) is invalid - this warning gets lost.
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# Keep a worrking version around in case the deprecation of the old API is
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# triggered.
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showwarning = _show_warning
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def formatwarning(message, category, filename, lineno, line=None):
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"""Function to format a warning the standard way."""
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s = "%s:%s: %s: %s\n" % (filename, lineno, category.__name__, message)
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line = linecache.getline(filename, lineno) if line is None else line
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if line:
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line = line.strip()
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s += " %s\n" % line
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return s
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def filterwarnings(action, message="", category=Warning, module="", lineno=0,
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append=0):
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"""Insert an entry into the list of warnings filters (at the front).
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Use assertions to check that all arguments have the right type."""
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import re
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assert action in ("error", "ignore", "always", "default", "module",
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"once"), "invalid action: %r" % (action,)
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assert isinstance(message, basestring), "message must be a string"
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assert isinstance(category, (type, types.ClassType)), \
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"category must be a class"
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assert issubclass(category, Warning), "category must be a Warning subclass"
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assert isinstance(module, basestring), "module must be a string"
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assert isinstance(lineno, int) and lineno >= 0, \
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"lineno must be an int >= 0"
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item = (action, re.compile(message, re.I), category,
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re.compile(module), lineno)
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if append:
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filters.append(item)
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else:
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filters.insert(0, item)
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def simplefilter(action, category=Warning, lineno=0, append=0):
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"""Insert a simple entry into the list of warnings filters (at the front).
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A simple filter matches all modules and messages.
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"""
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assert action in ("error", "ignore", "always", "default", "module",
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"once"), "invalid action: %r" % (action,)
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assert isinstance(lineno, int) and lineno >= 0, \
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"lineno must be an int >= 0"
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item = (action, None, category, None, lineno)
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if append:
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filters.append(item)
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else:
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filters.insert(0, item)
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def resetwarnings():
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"""Clear the list of warning filters, so that no filters are active."""
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filters[:] = []
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class _OptionError(Exception):
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"""Exception used by option processing helpers."""
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pass
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# Helper to process -W options passed via sys.warnoptions
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def _processoptions(args):
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for arg in args:
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try:
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_setoption(arg)
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except _OptionError, msg:
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print >>sys.stderr, "Invalid -W option ignored:", msg
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# Helper for _processoptions()
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def _setoption(arg):
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import re
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parts = arg.split(':')
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if len(parts) > 5:
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raise _OptionError("too many fields (max 5): %r" % (arg,))
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while len(parts) < 5:
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parts.append('')
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action, message, category, module, lineno = [s.strip()
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for s in parts]
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action = _getaction(action)
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message = re.escape(message)
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category = _getcategory(category)
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module = re.escape(module)
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if module:
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module = module + '$'
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if lineno:
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try:
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lineno = int(lineno)
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if lineno < 0:
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raise ValueError
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except (ValueError, OverflowError):
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raise _OptionError("invalid lineno %r" % (lineno,))
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else:
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lineno = 0
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filterwarnings(action, message, category, module, lineno)
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# Helper for _setoption()
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def _getaction(action):
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if not action:
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return "default"
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if action == "all": return "always" # Alias
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for a in ('default', 'always', 'ignore', 'module', 'once', 'error'):
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if a.startswith(action):
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return a
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raise _OptionError("invalid action: %r" % (action,))
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# Helper for _setoption()
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def _getcategory(category):
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import re
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if not category:
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return Warning
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if re.match("^[a-zA-Z0-9_]+$", category):
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try:
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cat = eval(category)
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except NameError:
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raise _OptionError("unknown warning category: %r" % (category,))
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else:
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i = category.rfind(".")
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module = category[:i]
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klass = category[i+1:]
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try:
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m = __import__(module, None, None, [klass])
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except ImportError:
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raise _OptionError("invalid module name: %r" % (module,))
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try:
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cat = getattr(m, klass)
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except AttributeError:
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raise _OptionError("unknown warning category: %r" % (category,))
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if not issubclass(cat, Warning):
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raise _OptionError("invalid warning category: %r" % (category,))
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return cat
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# Code typically replaced by _warnings
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def warn(message, category=None, stacklevel=1):
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"""Issue a warning, or maybe ignore it or raise an exception."""
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# Check if message is already a Warning object
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if isinstance(message, Warning):
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category = message.__class__
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# Check category argument
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if category is None:
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category = UserWarning
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assert issubclass(category, Warning)
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# Get context information
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try:
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caller = sys._getframe(stacklevel)
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except ValueError:
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globals = sys.__dict__
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lineno = 1
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else:
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globals = caller.f_globals
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lineno = caller.f_lineno
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if '__name__' in globals:
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module = globals['__name__']
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else:
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module = "<string>"
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filename = globals.get('__file__')
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if filename:
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fnl = filename.lower()
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if fnl.endswith((".pyc", ".pyo")):
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filename = filename[:-1]
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else:
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if module == "__main__":
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try:
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filename = sys.argv[0]
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except AttributeError:
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# embedded interpreters don't have sys.argv, see bug #839151
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filename = '__main__'
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if not filename:
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filename = module
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registry = globals.setdefault("__warningregistry__", {})
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warn_explicit(message, category, filename, lineno, module, registry,
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globals)
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def warn_explicit(message, category, filename, lineno,
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module=None, registry=None, module_globals=None):
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lineno = int(lineno)
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if module is None:
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module = filename or "<unknown>"
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if module[-3:].lower() == ".py":
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module = module[:-3] # XXX What about leading pathname?
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if registry is None:
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registry = {}
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if isinstance(message, Warning):
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text = str(message)
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category = message.__class__
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else:
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text = message
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message = category(message)
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key = (text, category, lineno)
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# Quick test for common case
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if registry.get(key):
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return
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# Search the filters
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for item in filters:
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action, msg, cat, mod, ln = item
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if ((msg is None or msg.match(text)) and
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issubclass(category, cat) and
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(mod is None or mod.match(module)) and
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(ln == 0 or lineno == ln)):
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break
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else:
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action = defaultaction
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# Early exit actions
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if action == "ignore":
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registry[key] = 1
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return
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# Prime the linecache for formatting, in case the
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# "file" is actually in a zipfile or something.
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linecache.getlines(filename, module_globals)
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if action == "error":
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raise message
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# Other actions
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if action == "once":
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registry[key] = 1
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oncekey = (text, category)
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if onceregistry.get(oncekey):
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return
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onceregistry[oncekey] = 1
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elif action == "always":
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pass
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elif action == "module":
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registry[key] = 1
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altkey = (text, category, 0)
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if registry.get(altkey):
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return
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registry[altkey] = 1
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elif action == "default":
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registry[key] = 1
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else:
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# Unrecognized actions are errors
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raise RuntimeError(
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"Unrecognized action (%r) in warnings.filters:\n %s" %
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(action, item))
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# Warn if showwarning() does not support the 'line' argument.
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# Don't use 'inspect' as it relies on an extension module, which break the
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# build thanks to 'warnings' being imported by setup.py.
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fxn_code = None
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if hasattr(showwarning, 'func_code'):
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fxn_code = showwarning.func_code
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elif hasattr(showwarning, '__func__'):
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fxn_code = showwarning.__func__.func_code
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if fxn_code:
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args = fxn_code.co_varnames[:fxn_code.co_argcount]
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CO_VARARGS = 0x4
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if 'line' not in args and not fxn_code.co_flags & CO_VARARGS:
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showwarning_msg = ("functions overriding warnings.showwarning() "
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"must support the 'line' argument")
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if message == showwarning_msg:
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_show_warning(message, category, filename, lineno)
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else:
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warn(showwarning_msg, DeprecationWarning)
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# Print message and context
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showwarning(message, category, filename, lineno)
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class WarningMessage(object):
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"""Holds the result of a single showwarning() call."""
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_WARNING_DETAILS = ("message", "category", "filename", "lineno", "file",
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"line")
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def __init__(self, message, category, filename, lineno, file=None,
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line=None):
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local_values = locals()
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for attr in self._WARNING_DETAILS:
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setattr(self, attr, local_values[attr])
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self._category_name = category.__name__ if category else None
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def __str__(self):
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return ("{message : %r, category : %r, filename : %r, lineno : %s, "
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"line : %r}" % (self.message, self._category_name,
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self.filename, self.lineno, self.line))
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class catch_warnings(object):
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"""A context manager that copies and restores the warnings filter upon
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exiting the context.
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The 'record' argument specifies whether warnings should be captured by a
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custom implementation of warnings.showwarning() and be appended to a list
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returned by the context manager. Otherwise None is returned by the context
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manager. The objects appended to the list are arguments whose attributes
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mirror the arguments to showwarning().
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The 'module' argument is to specify an alternative module to the module
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named 'warnings' and imported under that name. This argument is only useful
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when testing the warnings module itself.
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"""
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def __init__(self, record=False, module=None):
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"""Specify whether to record warnings and if an alternative module
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should be used other than sys.modules['warnings'].
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For compatibility with Python 3.0, please consider all arguments to be
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keyword-only.
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"""
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self._record = record
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self._module = sys.modules['warnings'] if module is None else module
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def __enter__(self):
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self._filters = self._module.filters
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self._module.filters = self._filters[:]
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self._showwarning = self._module.showwarning
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if self._record:
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log = []
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def showwarning(*args, **kwargs):
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log.append(WarningMessage(*args, **kwargs))
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self._module.showwarning = showwarning
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return log
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else:
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return None
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def __exit__(self, *exc_info):
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self._module.filters = self._filters
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self._module.showwarning = self._showwarning
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# filters contains a sequence of filter 5-tuples
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# The components of the 5-tuple are:
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# - an action: error, ignore, always, default, module, or once
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# - a compiled regex that must match the warning message
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# - a class representing the warning category
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# - a compiled regex that must match the module that is being warned
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# - a line number for the line being warning, or 0 to mean any line
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# If either if the compiled regexs are None, match anything.
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_warnings_defaults = False
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try:
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from _warnings import (filters, default_action, once_registry,
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warn, warn_explicit)
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defaultaction = default_action
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onceregistry = once_registry
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_warnings_defaults = True
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except ImportError:
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filters = []
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defaultaction = "default"
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onceregistry = {}
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# Module initialization
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_processoptions(sys.warnoptions)
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if not _warnings_defaults:
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simplefilter("ignore", category=PendingDeprecationWarning, append=1)
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simplefilter("ignore", category=ImportWarning, append=1)
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bytes_warning = sys.flags.bytes_warning
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if bytes_warning > 1:
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bytes_action = "error"
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elif bytes_warning:
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bytes_action = "default"
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else:
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bytes_action = "ignore"
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simplefilter(bytes_action, category=BytesWarning, append=1)
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del _warnings_defaults
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