"""Python part of the warnings subsystem.""" import sys __all__ = ["warn", "warn_explicit", "showwarning", "formatwarning", "filterwarnings", "simplefilter", "resetwarnings", "catch_warnings"] def showwarning(message, category, filename, lineno, file=None, line=None): """Hook to write a warning to a file; replace if you like.""" if file is None: file = sys.stderr if file is None: # sys.stderr is None when run with pythonw.exe - warnings get lost return try: file.write(formatwarning(message, category, filename, lineno, line)) except OSError: pass # the file (probably stderr) is invalid - this warning gets lost. def formatwarning(message, category, filename, lineno, line=None): """Function to format a warning the standard way.""" import linecache s = "%s:%s: %s: %s\n" % (filename, lineno, category.__name__, message) line = linecache.getline(filename, lineno) if line is None else line if line: line = line.strip() s += " %s\n" % line return s def filterwarnings(action, message="", category=Warning, module="", lineno=0, append=False): """Insert an entry into the list of warnings filters (at the front). 'action' -- one of "error", "ignore", "always", "default", "module", or "once" 'message' -- a regex that the warning message must match 'category' -- a class that the warning must be a subclass of 'module' -- a regex that the module name must match 'lineno' -- an integer line number, 0 matches all warnings 'append' -- if true, append to the list of filters """ import re assert action in ("error", "ignore", "always", "default", "module", "once"), "invalid action: %r" % (action,) assert isinstance(message, str), "message must be a string" assert isinstance(category, type), "category must be a class" assert issubclass(category, Warning), "category must be a Warning subclass" assert isinstance(module, str), "module must be a string" assert isinstance(lineno, int) and lineno >= 0, \ "lineno must be an int >= 0" item = (action, re.compile(message, re.I), category, re.compile(module), lineno) if append: filters.append(item) else: filters.insert(0, item) _filters_mutated() def simplefilter(action, category=Warning, lineno=0, append=False): """Insert a simple entry into the list of warnings filters (at the front). A simple filter matches all modules and messages. 'action' -- one of "error", "ignore", "always", "default", "module", or "once" 'category' -- a class that the warning must be a subclass of 'lineno' -- an integer line number, 0 matches all warnings 'append' -- if true, append to the list of filters """ assert action in ("error", "ignore", "always", "default", "module", "once"), "invalid action: %r" % (action,) assert isinstance(lineno, int) and lineno >= 0, \ "lineno must be an int >= 0" item = (action, None, category, None, lineno) if append: filters.append(item) else: filters.insert(0, item) _filters_mutated() def resetwarnings(): """Clear the list of warning filters, so that no filters are active.""" filters[:] = [] _filters_mutated() class _OptionError(Exception): """Exception used by option processing helpers.""" pass # Helper to process -W options passed via sys.warnoptions def _processoptions(args): for arg in args: try: _setoption(arg) except _OptionError as msg: print("Invalid -W option ignored:", msg, file=sys.stderr) # Helper for _processoptions() def _setoption(arg): import re parts = arg.split(':') if len(parts) > 5: raise _OptionError("too many fields (max 5): %r" % (arg,)) while len(parts) < 5: parts.append('') action, message, category, module, lineno = [s.strip() for s in parts] action = _getaction(action) message = re.escape(message) category = _getcategory(category) module = re.escape(module) if module: module = module + '$' if lineno: try: lineno = int(lineno) if lineno < 0: raise ValueError except (ValueError, OverflowError): raise _OptionError("invalid lineno %r" % (lineno,)) else: lineno = 0 filterwarnings(action, message, category, module, lineno) # Helper for _setoption() def _getaction(action): if not action: return "default" if action == "all": return "always" # Alias for a in ('default', 'always', 'ignore', 'module', 'once', 'error'): if a.startswith(action): return a raise _OptionError("invalid action: %r" % (action,)) # Helper for _setoption() def _getcategory(category): import re if not category: return Warning if re.match("^[a-zA-Z0-9_]+$", category): try: cat = eval(category) except NameError: raise _OptionError("unknown warning category: %r" % (category,)) else: i = category.rfind(".") module = category[:i] klass = category[i+1:] try: m = __import__(module, None, None, [klass]) except ImportError: raise _OptionError("invalid module name: %r" % (module,)) try: cat = getattr(m, klass) except AttributeError: raise _OptionError("unknown warning category: %r" % (category,)) if not issubclass(cat, Warning): raise _OptionError("invalid warning category: %r" % (category,)) return cat # Code typically replaced by _warnings def warn(message, category=None, stacklevel=1): """Issue a warning, or maybe ignore it or raise an exception.""" # Check if message is already a Warning object if isinstance(message, Warning): category = message.__class__ # Check category argument if category is None: category = UserWarning assert issubclass(category, Warning) # Get context information try: caller = sys._getframe(stacklevel) except ValueError: globals = sys.__dict__ lineno = 1 else: globals = caller.f_globals lineno = caller.f_lineno if '__name__' in globals: module = globals['__name__'] else: module = "" filename = globals.get('__file__') if filename: fnl = filename.lower() if fnl.endswith((".pyc", ".pyo")): filename = filename[:-1] else: if module == "__main__": try: filename = sys.argv[0] except AttributeError: # embedded interpreters don't have sys.argv, see bug #839151 filename = '__main__' if not filename: filename = module registry = globals.setdefault("__warningregistry__", {}) warn_explicit(message, category, filename, lineno, module, registry, globals) def warn_explicit(message, category, filename, lineno, module=None, registry=None, module_globals=None): lineno = int(lineno) if module is None: module = filename or "" if module[-3:].lower() == ".py": module = module[:-3] # XXX What about leading pathname? if registry is None: registry = {} if registry.get('version', 0) != _filters_version: registry.clear() registry['version'] = _filters_version if isinstance(message, Warning): text = str(message) category = message.__class__ else: text = message message = category(message) key = (text, category, lineno) # Quick test for common case if registry.get(key): return # Search the filters for item in filters: action, msg, cat, mod, ln = item if ((msg is None or msg.match(text)) and issubclass(category, cat) and (mod is None or mod.match(module)) and (ln == 0 or lineno == ln)): break else: action = defaultaction # Early exit actions if action == "ignore": registry[key] = 1 return # Prime the linecache for formatting, in case the # "file" is actually in a zipfile or something. import linecache linecache.getlines(filename, module_globals) if action == "error": raise message # Other actions if action == "once": registry[key] = 1 oncekey = (text, category) if onceregistry.get(oncekey): return onceregistry[oncekey] = 1 elif action == "always": pass elif action == "module": registry[key] = 1 altkey = (text, category, 0) if registry.get(altkey): return registry[altkey] = 1 elif action == "default": registry[key] = 1 else: # Unrecognized actions are errors raise RuntimeError( "Unrecognized action (%r) in warnings.filters:\n %s" % (action, item)) if not callable(showwarning): raise TypeError("warnings.showwarning() must be set to a " "function or method") # Print message and context showwarning(message, category, filename, lineno) class WarningMessage(object): """Holds the result of a single showwarning() call.""" _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file", "line") def __init__(self, message, category, filename, lineno, file=None, line=None): local_values = locals() for attr in self._WARNING_DETAILS: setattr(self, attr, local_values[attr]) self._category_name = category.__name__ if category else None def __str__(self): return ("{message : %r, category : %r, filename : %r, lineno : %s, " "line : %r}" % (self.message, self._category_name, self.filename, self.lineno, self.line)) class catch_warnings(object): """A context manager that copies and restores the warnings filter upon exiting the context. The 'record' argument specifies whether warnings should be captured by a custom implementation of warnings.showwarning() and be appended to a list returned by the context manager. Otherwise None is returned by the context manager. The objects appended to the list are arguments whose attributes mirror the arguments to showwarning(). The 'module' argument is to specify an alternative module to the module named 'warnings' and imported under that name. This argument is only useful when testing the warnings module itself. """ def __init__(self, *, record=False, module=None): """Specify whether to record warnings and if an alternative module should be used other than sys.modules['warnings']. For compatibility with Python 3.0, please consider all arguments to be keyword-only. """ self._record = record self._module = sys.modules['warnings'] if module is None else module self._entered = False def __repr__(self): args = [] if self._record: args.append("record=True") if self._module is not sys.modules['warnings']: args.append("module=%r" % self._module) name = type(self).__name__ return "%s(%s)" % (name, ", ".join(args)) def __enter__(self): if self._entered: raise RuntimeError("Cannot enter %r twice" % self) self._entered = True self._filters = self._module.filters self._module.filters = self._filters[:] self._module._filters_mutated() self._showwarning = self._module.showwarning if self._record: log = [] def showwarning(*args, **kwargs): log.append(WarningMessage(*args, **kwargs)) self._module.showwarning = showwarning return log else: return None def __exit__(self, *exc_info): if not self._entered: raise RuntimeError("Cannot exit %r without entering first" % self) self._module.filters = self._filters self._module._filters_mutated() self._module.showwarning = self._showwarning # filters contains a sequence of filter 5-tuples # The components of the 5-tuple are: # - an action: error, ignore, always, default, module, or once # - a compiled regex that must match the warning message # - a class representing the warning category # - a compiled regex that must match the module that is being warned # - a line number for the line being warning, or 0 to mean any line # If either if the compiled regexs are None, match anything. _warnings_defaults = False try: from _warnings import (filters, _defaultaction, _onceregistry, warn, warn_explicit, _filters_mutated) defaultaction = _defaultaction onceregistry = _onceregistry _warnings_defaults = True except ImportError: filters = [] defaultaction = "default" onceregistry = {} _filters_version = 1 def _filters_mutated(): global _filters_version _filters_version += 1 # Module initialization _processoptions(sys.warnoptions) if not _warnings_defaults: silence = [ImportWarning, PendingDeprecationWarning] silence.append(DeprecationWarning) for cls in silence: simplefilter("ignore", category=cls) bytes_warning = sys.flags.bytes_warning if bytes_warning > 1: bytes_action = "error" elif bytes_warning: bytes_action = "default" else: bytes_action = "ignore" simplefilter(bytes_action, category=BytesWarning, append=1) # resource usage warnings are enabled by default in pydebug mode if hasattr(sys, 'gettotalrefcount'): resource_action = "always" else: resource_action = "ignore" simplefilter(resource_action, category=ResourceWarning, append=1) del _warnings_defaults