1 """Python part of the warnings subsystem."""
3 # Note: function level imports should *not* be used
4 # in this module as it may cause import lock deadlock.
10 __all__
= ["warn", "showwarning", "formatwarning", "filterwarnings",
11 "resetwarnings", "catch_warnings"]
14 def warnpy3k(message
, category
=None, stacklevel
=1):
15 """Issue a deprecation warning for Python 3.x related changes.
17 Warnings are omitted unless Python is started with the -3 option.
21 category
= DeprecationWarning
22 warn(message
, category
, stacklevel
+1)
24 def _show_warning(message
, category
, filename
, lineno
, file=None, line
=None):
25 """Hook to write a warning to a file; replace if you like."""
29 file.write(formatwarning(message
, category
, filename
, lineno
, line
))
31 pass # the file (probably stderr) is invalid - this warning gets lost.
32 # Keep a worrking version around in case the deprecation of the old API is
34 showwarning
= _show_warning
36 def formatwarning(message
, category
, filename
, lineno
, line
=None):
37 """Function to format a warning the standard way."""
38 s
= "%s:%s: %s: %s\n" % (filename
, lineno
, category
.__name
__, message
)
39 line
= linecache
.getline(filename
, lineno
) if line
is None else line
45 def filterwarnings(action
, message
="", category
=Warning, module
="", lineno
=0,
47 """Insert an entry into the list of warnings filters (at the front).
49 Use assertions to check that all arguments have the right type."""
51 assert action
in ("error", "ignore", "always", "default", "module",
52 "once"), "invalid action: %r" % (action
,)
53 assert isinstance(message
, basestring
), "message must be a string"
54 assert isinstance(category
, (type, types
.ClassType
)), \
55 "category must be a class"
56 assert issubclass(category
, Warning), "category must be a Warning subclass"
57 assert isinstance(module
, basestring
), "module must be a string"
58 assert isinstance(lineno
, int) and lineno
>= 0, \
59 "lineno must be an int >= 0"
60 item
= (action
, re
.compile(message
, re
.I
), category
,
61 re
.compile(module
), lineno
)
65 filters
.insert(0, item
)
67 def simplefilter(action
, category
=Warning, lineno
=0, append
=0):
68 """Insert a simple entry into the list of warnings filters (at the front).
70 A simple filter matches all modules and messages.
72 assert action
in ("error", "ignore", "always", "default", "module",
73 "once"), "invalid action: %r" % (action
,)
74 assert isinstance(lineno
, int) and lineno
>= 0, \
75 "lineno must be an int >= 0"
76 item
= (action
, None, category
, None, lineno
)
80 filters
.insert(0, item
)
83 """Clear the list of warning filters, so that no filters are active."""
86 class _OptionError(Exception):
87 """Exception used by option processing helpers."""
90 # Helper to process -W options passed via sys.warnoptions
91 def _processoptions(args
):
95 except _OptionError
, msg
:
96 print >>sys
.stderr
, "Invalid -W option ignored:", msg
98 # Helper for _processoptions()
101 parts
= arg
.split(':')
103 raise _OptionError("too many fields (max 5): %r" % (arg
,))
104 while len(parts
) < 5:
106 action
, message
, category
, module
, lineno
= [s
.strip()
108 action
= _getaction(action
)
109 message
= re
.escape(message
)
110 category
= _getcategory(category
)
111 module
= re
.escape(module
)
113 module
= module
+ '$'
119 except (ValueError, OverflowError):
120 raise _OptionError("invalid lineno %r" % (lineno
,))
123 filterwarnings(action
, message
, category
, module
, lineno
)
125 # Helper for _setoption()
126 def _getaction(action
):
129 if action
== "all": return "always" # Alias
130 for a
in ('default', 'always', 'ignore', 'module', 'once', 'error'):
131 if a
.startswith(action
):
133 raise _OptionError("invalid action: %r" % (action
,))
135 # Helper for _setoption()
136 def _getcategory(category
):
140 if re
.match("^[a-zA-Z0-9_]+$", category
):
144 raise _OptionError("unknown warning category: %r" % (category
,))
146 i
= category
.rfind(".")
147 module
= category
[:i
]
148 klass
= category
[i
+1:]
150 m
= __import__(module
, None, None, [klass
])
152 raise _OptionError("invalid module name: %r" % (module
,))
154 cat
= getattr(m
, klass
)
155 except AttributeError:
156 raise _OptionError("unknown warning category: %r" % (category
,))
157 if not issubclass(cat
, Warning):
158 raise _OptionError("invalid warning category: %r" % (category
,))
162 # Code typically replaced by _warnings
163 def warn(message
, category
=None, stacklevel
=1):
164 """Issue a warning, or maybe ignore it or raise an exception."""
165 # Check if message is already a Warning object
166 if isinstance(message
, Warning):
167 category
= message
.__class
__
168 # Check category argument
170 category
= UserWarning
171 assert issubclass(category
, Warning)
172 # Get context information
174 caller
= sys
._getframe
(stacklevel
)
176 globals = sys
.__dict
__
179 globals = caller
.f_globals
180 lineno
= caller
.f_lineno
181 if '__name__' in globals:
182 module
= globals['__name__']
185 filename
= globals.get('__file__')
187 fnl
= filename
.lower()
188 if fnl
.endswith((".pyc", ".pyo")):
189 filename
= filename
[:-1]
191 if module
== "__main__":
193 filename
= sys
.argv
[0]
194 except AttributeError:
195 # embedded interpreters don't have sys.argv, see bug #839151
196 filename
= '__main__'
199 registry
= globals.setdefault("__warningregistry__", {})
200 warn_explicit(message
, category
, filename
, lineno
, module
, registry
,
203 def warn_explicit(message
, category
, filename
, lineno
,
204 module
=None, registry
=None, module_globals
=None):
207 module
= filename
or "<unknown>"
208 if module
[-3:].lower() == ".py":
209 module
= module
[:-3] # XXX What about leading pathname?
212 if isinstance(message
, Warning):
214 category
= message
.__class
__
217 message
= category(message
)
218 key
= (text
, category
, lineno
)
219 # Quick test for common case
220 if registry
.get(key
):
224 action
, msg
, cat
, mod
, ln
= item
225 if ((msg
is None or msg
.match(text
)) and
226 issubclass(category
, cat
) and
227 (mod
is None or mod
.match(module
)) and
228 (ln
== 0 or lineno
== ln
)):
231 action
= defaultaction
233 if action
== "ignore":
237 # Prime the linecache for formatting, in case the
238 # "file" is actually in a zipfile or something.
239 linecache
.getlines(filename
, module_globals
)
241 if action
== "error":
246 oncekey
= (text
, category
)
247 if onceregistry
.get(oncekey
):
249 onceregistry
[oncekey
] = 1
250 elif action
== "always":
252 elif action
== "module":
254 altkey
= (text
, category
, 0)
255 if registry
.get(altkey
):
258 elif action
== "default":
261 # Unrecognized actions are errors
263 "Unrecognized action (%r) in warnings.filters:\n %s" %
265 # Print message and context
266 showwarning(message
, category
, filename
, lineno
)
269 class WarningMessage(object):
271 """Holds the result of a single showwarning() call."""
273 _WARNING_DETAILS
= ("message", "category", "filename", "lineno", "file",
276 def __init__(self
, message
, category
, filename
, lineno
, file=None,
278 local_values
= locals()
279 for attr
in self
._WARNING
_DETAILS
:
280 setattr(self
, attr
, local_values
[attr
])
281 self
._category
_name
= category
.__name
__ if category
else None
284 return ("{message : %r, category : %r, filename : %r, lineno : %s, "
285 "line : %r}" % (self
.message
, self
._category
_name
,
286 self
.filename
, self
.lineno
, self
.line
))
289 class catch_warnings(object):
291 """A context manager that copies and restores the warnings filter upon
294 The 'record' argument specifies whether warnings should be captured by a
295 custom implementation of warnings.showwarning() and be appended to a list
296 returned by the context manager. Otherwise None is returned by the context
297 manager. The objects appended to the list are arguments whose attributes
298 mirror the arguments to showwarning().
300 The 'module' argument is to specify an alternative module to the module
301 named 'warnings' and imported under that name. This argument is only useful
302 when testing the warnings module itself.
306 def __init__(self
, record
=False, module
=None):
307 """Specify whether to record warnings and if an alternative module
308 should be used other than sys.modules['warnings'].
310 For compatibility with Python 3.0, please consider all arguments to be
314 self
._record
= record
315 self
._module
= sys
.modules
['warnings'] if module
is None else module
316 self
._entered
= False
321 args
.append("record=True")
322 if self
._module
is not sys
.modules
['warnings']:
323 args
.append("module=%r" % self
._module
)
324 name
= type(self
).__name
__
325 return "%s(%s)" % (name
, ", ".join(args
))
329 raise RuntimeError("Cannot enter %r twice" % self
)
331 self
._filters
= self
._module
.filters
332 self
._module
.filters
= self
._filters
[:]
333 self
._showwarning
= self
._module
.showwarning
336 def showwarning(*args
, **kwargs
):
337 log
.append(WarningMessage(*args
, **kwargs
))
338 self
._module
.showwarning
= showwarning
343 def __exit__(self
, *exc_info
):
344 if not self
._entered
:
345 raise RuntimeError("Cannot exit %r without entering first" % self
)
346 self
._module
.filters
= self
._filters
347 self
._module
.showwarning
= self
._showwarning
350 # filters contains a sequence of filter 5-tuples
351 # The components of the 5-tuple are:
352 # - an action: error, ignore, always, default, module, or once
353 # - a compiled regex that must match the warning message
354 # - a class representing the warning category
355 # - a compiled regex that must match the module that is being warned
356 # - a line number for the line being warning, or 0 to mean any line
357 # If either if the compiled regexs are None, match anything.
358 _warnings_defaults
= False
360 from _warnings
import (filters
, default_action
, once_registry
,
362 defaultaction
= default_action
363 onceregistry
= once_registry
364 _warnings_defaults
= True
367 defaultaction
= "default"
371 # Module initialization
372 _processoptions(sys
.warnoptions
)
373 if not _warnings_defaults
:
374 simplefilter("ignore", category
=PendingDeprecationWarning
, append
=1)
375 simplefilter("ignore", category
=ImportWarning
, append
=1)
376 bytes_warning
= sys
.flags
.bytes_warning
377 if bytes_warning
> 1:
378 bytes_action
= "error"
380 bytes_action
= "default"
382 bytes_action
= "ignore"
383 simplefilter(bytes_action
, category
=BytesWarning
, append
=1)
384 del _warnings_defaults