ref: 5b81e7de3f1ab3691438878cf1da912a54138d5f
dir: /sys/lib/python/warnings.py/
"""Python part of the warnings subsystem."""
# Note: function level imports should *not* be used
# in this module as it may cause import lock deadlock.
# See bug 683658.
import sys, types
import linecache
__all__ = ["warn", "showwarning", "formatwarning", "filterwarnings",
"resetwarnings"]
# 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.
filters = []
defaultaction = "default"
onceregistry = {}
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 = "<string>"
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):
if module is None:
module = filename or "<unknown>"
if module[-3:].lower() == ".py":
module = module[:-3] # XXX What about leading pathname?
if registry is None:
registry = {}
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.
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))
# Print message and context
showwarning(message, category, filename, lineno)
def showwarning(message, category, filename, lineno, file=None):
"""Hook to write a warning to a file; replace if you like."""
if file is None:
file = sys.stderr
try:
file.write(formatwarning(message, category, filename, lineno))
except IOError:
pass # the file (probably stderr) is invalid - this warning gets lost.
def formatwarning(message, category, filename, lineno):
"""Function to format a warning the standard way."""
s = "%s:%s: %s: %s\n" % (filename, lineno, category.__name__, message)
line = linecache.getline(filename, lineno).strip()
if line:
s = s + " " + line + "\n"
return s
def filterwarnings(action, message="", category=Warning, module="", lineno=0,
append=0):
"""Insert an entry into the list of warnings filters (at the front).
Use assertions to check that all arguments have the right type."""
import re
assert action in ("error", "ignore", "always", "default", "module",
"once"), "invalid action: %r" % (action,)
assert isinstance(message, basestring), "message must be a string"
assert isinstance(category, (type, types.ClassType)), \
"category must be a class"
assert issubclass(category, Warning), "category must be a Warning subclass"
assert isinstance(module, basestring), "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)
def simplefilter(action, category=Warning, lineno=0, append=0):
"""Insert a simple entry into the list of warnings filters (at the front).
A simple filter matches all modules and messages.
"""
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)
def resetwarnings():
"""Clear the list of warning filters, so that no filters are active."""
filters[:] = []
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, msg:
print >>sys.stderr, "Invalid -W option ignored:", msg
# 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
# Module initialization
_processoptions(sys.warnoptions)
simplefilter("ignore", category=PendingDeprecationWarning, append=1)
simplefilter("ignore", category=ImportWarning, append=1)