| Index: third_party/pylint/pylint/checkers/exceptions.py
|
| diff --git a/third_party/pylint/pylint/checkers/exceptions.py b/third_party/pylint/pylint/checkers/exceptions.py
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..88a8f225e2e80304f8959fbcbe1a39a0aed02267
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| --- /dev/null
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| +++ b/third_party/pylint/pylint/checkers/exceptions.py
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| @@ -0,0 +1,332 @@
|
| +# Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
|
| +# http://www.logilab.fr/ -- mailto:contact@logilab.fr
|
| +# This program is free software; you can redistribute it and/or modify it under
|
| +# the terms of the GNU General Public License as published by the Free Software
|
| +# Foundation; either version 2 of the License, or (at your option) any later
|
| +# version.
|
| +#
|
| +# This program is distributed in the hope that it will be useful, but WITHOUT
|
| +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
| +# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
|
| +#
|
| +# You should have received a copy of the GNU General Public License along with
|
| +# this program; if not, write to the Free Software Foundation, Inc.,
|
| +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
| +"""exceptions handling (raising, catching, exceptions classes) checker
|
| +"""
|
| +import sys
|
| +
|
| +import astroid
|
| +from astroid import YES, Instance, unpack_infer, List, Tuple
|
| +from logilab.common.compat import builtins
|
| +
|
| +from pylint.checkers import BaseChecker
|
| +from pylint.checkers.utils import (
|
| + is_empty,
|
| + is_raising,
|
| + check_messages,
|
| + inherit_from_std_ex,
|
| + EXCEPTIONS_MODULE,
|
| + has_known_bases,
|
| + safe_infer)
|
| +from pylint.interfaces import IAstroidChecker, INFERENCE, INFERENCE_FAILURE
|
| +
|
| +
|
| +def _annotated_unpack_infer(stmt, context=None):
|
| + """
|
| + Recursively generate nodes inferred by the given statement.
|
| + If the inferred value is a list or a tuple, recurse on the elements.
|
| + Returns an iterator which yields tuples in the format
|
| + ('original node', 'infered node').
|
| + """
|
| + if isinstance(stmt, (List, Tuple)):
|
| + for elt in stmt.elts:
|
| + inferred = safe_infer(elt)
|
| + if inferred and inferred is not YES:
|
| + yield elt, inferred
|
| + return
|
| + for infered in stmt.infer(context):
|
| + if infered is YES:
|
| + continue
|
| + yield stmt, infered
|
| +
|
| +
|
| +PY3K = sys.version_info >= (3, 0)
|
| +OVERGENERAL_EXCEPTIONS = ('Exception',)
|
| +BUILTINS_NAME = builtins.__name__
|
| +MSGS = {
|
| + 'E0701': ('Bad except clauses order (%s)',
|
| + 'bad-except-order',
|
| + 'Used when except clauses are not in the correct order (from the '
|
| + 'more specific to the more generic). If you don\'t fix the order, '
|
| + 'some exceptions may not be catched by the most specific handler.'),
|
| + 'E0702': ('Raising %s while only classes or instances are allowed',
|
| + 'raising-bad-type',
|
| + 'Used when something which is neither a class, an instance or a \
|
| + string is raised (i.e. a `TypeError` will be raised).'),
|
| + 'E0703': ('Exception context set to something which is not an '
|
| + 'exception, nor None',
|
| + 'bad-exception-context',
|
| + 'Used when using the syntax "raise ... from ...", '
|
| + 'where the exception context is not an exception, '
|
| + 'nor None.',
|
| + {'minversion': (3, 0)}),
|
| + 'E0710': ('Raising a new style class which doesn\'t inherit from BaseException',
|
| + 'raising-non-exception',
|
| + 'Used when a new style class which doesn\'t inherit from \
|
| + BaseException is raised.'),
|
| + 'E0711': ('NotImplemented raised - should raise NotImplementedError',
|
| + 'notimplemented-raised',
|
| + 'Used when NotImplemented is raised instead of \
|
| + NotImplementedError'),
|
| + 'E0712': ('Catching an exception which doesn\'t inherit from BaseException: %s',
|
| + 'catching-non-exception',
|
| + 'Used when a class which doesn\'t inherit from \
|
| + BaseException is used as an exception in an except clause.'),
|
| + 'W0702': ('No exception type(s) specified',
|
| + 'bare-except',
|
| + 'Used when an except clause doesn\'t specify exceptions type to \
|
| + catch.'),
|
| + 'W0703': ('Catching too general exception %s',
|
| + 'broad-except',
|
| + 'Used when an except catches a too general exception, \
|
| + possibly burying unrelated errors.'),
|
| + 'W0704': ('Except doesn\'t do anything',
|
| + 'pointless-except',
|
| + 'Used when an except clause does nothing but "pass" and there is\
|
| + no "else" clause.'),
|
| + 'W0710': ('Exception doesn\'t inherit from standard "Exception" class',
|
| + 'nonstandard-exception',
|
| + 'Used when a custom exception class is raised but doesn\'t \
|
| + inherit from the builtin "Exception" class.',
|
| + {'maxversion': (3, 0)}),
|
| + 'W0711': ('Exception to catch is the result of a binary "%s" operation',
|
| + 'binary-op-exception',
|
| + 'Used when the exception to catch is of the form \
|
| + "except A or B:". If intending to catch multiple, \
|
| + rewrite as "except (A, B):"'),
|
| + }
|
| +
|
| +
|
| +class ExceptionsChecker(BaseChecker):
|
| + """checks for
|
| + * excepts without exception filter
|
| + * type of raise argument : string, Exceptions, other values
|
| + """
|
| +
|
| + __implements__ = IAstroidChecker
|
| +
|
| + name = 'exceptions'
|
| + msgs = MSGS
|
| + priority = -4
|
| + options = (('overgeneral-exceptions',
|
| + {'default' : OVERGENERAL_EXCEPTIONS,
|
| + 'type' :'csv', 'metavar' : '<comma-separated class names>',
|
| + 'help' : 'Exceptions that will emit a warning '
|
| + 'when being caught. Defaults to "%s"' % (
|
| + ', '.join(OVERGENERAL_EXCEPTIONS),)}
|
| + ),
|
| + )
|
| +
|
| + @check_messages('nonstandard-exception',
|
| + 'raising-bad-type', 'raising-non-exception',
|
| + 'notimplemented-raised', 'bad-exception-context')
|
| + def visit_raise(self, node):
|
| + """visit raise possibly inferring value"""
|
| + # ignore empty raise
|
| + if node.exc is None:
|
| + return
|
| + if PY3K and node.cause:
|
| + self._check_bad_exception_context(node)
|
| +
|
| + expr = node.exc
|
| + if self._check_raise_value(node, expr):
|
| + return
|
| + else:
|
| + try:
|
| + value = next(unpack_infer(expr))
|
| + except astroid.InferenceError:
|
| + return
|
| + self._check_raise_value(node, value)
|
| +
|
| + def _check_bad_exception_context(self, node):
|
| + """Verify that the exception context is properly set.
|
| +
|
| + An exception context can be only `None` or an exception.
|
| + """
|
| + cause = safe_infer(node.cause)
|
| + if cause in (YES, None):
|
| + return
|
| + if isinstance(cause, astroid.Const):
|
| + if cause.value is not None:
|
| + self.add_message('bad-exception-context',
|
| + node=node)
|
| + elif (not isinstance(cause, astroid.Class) and
|
| + not inherit_from_std_ex(cause)):
|
| + self.add_message('bad-exception-context',
|
| + node=node)
|
| +
|
| + def _check_raise_value(self, node, expr):
|
| + """check for bad values, string exception and class inheritance
|
| + """
|
| + value_found = True
|
| + if isinstance(expr, astroid.Const):
|
| + value = expr.value
|
| + if not isinstance(value, str):
|
| + # raising-string will be emitted from python3 porting checker.
|
| + self.add_message('raising-bad-type', node=node,
|
| + args=value.__class__.__name__)
|
| + elif ((isinstance(expr, astroid.Name) and
|
| + expr.name in ('None', 'True', 'False')) or
|
| + isinstance(expr, (astroid.List, astroid.Dict, astroid.Tuple,
|
| + astroid.Module, astroid.Function))):
|
| + emit = True
|
| + if not PY3K and isinstance(expr, astroid.Tuple):
|
| + # On Python 2, using the following is not an error:
|
| + # raise (ZeroDivisionError, None)
|
| + # raise (ZeroDivisionError, )
|
| + # What's left to do is to check that the first
|
| + # argument is indeed an exception.
|
| + # Verifying the other arguments is not
|
| + # the scope of this check.
|
| + first = expr.elts[0]
|
| + inferred = safe_infer(first)
|
| + if isinstance(inferred, Instance):
|
| + # pylint: disable=protected-access
|
| + inferred = inferred._proxied
|
| + if (inferred is YES or
|
| + isinstance(inferred, astroid.Class)
|
| + and inherit_from_std_ex(inferred)):
|
| + emit = False
|
| + if emit:
|
| + self.add_message('raising-bad-type',
|
| + node=node,
|
| + args=expr.name)
|
| + elif ((isinstance(expr, astroid.Name) and expr.name == 'NotImplemented')
|
| + or (isinstance(expr, astroid.CallFunc) and
|
| + isinstance(expr.func, astroid.Name) and
|
| + expr.func.name == 'NotImplemented')):
|
| + self.add_message('notimplemented-raised', node=node)
|
| + elif isinstance(expr, (Instance, astroid.Class)):
|
| + if isinstance(expr, Instance):
|
| + # pylint: disable=protected-access
|
| + expr = expr._proxied
|
| + if (isinstance(expr, astroid.Class) and
|
| + not inherit_from_std_ex(expr)):
|
| + if expr.newstyle:
|
| + self.add_message('raising-non-exception', node=node)
|
| + else:
|
| + if has_known_bases(expr):
|
| + confidence = INFERENCE
|
| + else:
|
| + confidence = INFERENCE_FAILURE
|
| + self.add_message(
|
| + 'nonstandard-exception', node=node,
|
| + confidence=confidence)
|
| + else:
|
| + value_found = False
|
| + else:
|
| + value_found = False
|
| + return value_found
|
| +
|
| + def _check_catching_non_exception(self, handler, exc, part):
|
| + if isinstance(exc, astroid.Tuple):
|
| + # Check if it is a tuple of exceptions.
|
| + inferred = [safe_infer(elt) for elt in exc.elts]
|
| + if any(node is astroid.YES for node in inferred):
|
| + # Don't emit if we don't know every component.
|
| + return
|
| + if all(node and inherit_from_std_ex(node)
|
| + for node in inferred):
|
| + return
|
| +
|
| + if not isinstance(exc, astroid.Class):
|
| + # Don't emit the warning if the infered stmt
|
| + # is None, but the exception handler is something else,
|
| + # maybe it was redefined.
|
| + if (isinstance(exc, astroid.Const) and
|
| + exc.value is None):
|
| + if ((isinstance(handler.type, astroid.Const) and
|
| + handler.type.value is None) or
|
| + handler.type.parent_of(exc)):
|
| + # If the exception handler catches None or
|
| + # the exception component, which is None, is
|
| + # defined by the entire exception handler, then
|
| + # emit a warning.
|
| + self.add_message('catching-non-exception',
|
| + node=handler.type,
|
| + args=(part.as_string(), ))
|
| + else:
|
| + self.add_message('catching-non-exception',
|
| + node=handler.type,
|
| + args=(part.as_string(), ))
|
| + return
|
| + if (not inherit_from_std_ex(exc) and
|
| + exc.root().name != BUILTINS_NAME):
|
| + if has_known_bases(exc):
|
| + self.add_message('catching-non-exception',
|
| + node=handler.type,
|
| + args=(exc.name, ))
|
| +
|
| + @check_messages('bare-except', 'broad-except', 'pointless-except',
|
| + 'binary-op-exception', 'bad-except-order',
|
| + 'catching-non-exception')
|
| + def visit_tryexcept(self, node):
|
| + """check for empty except"""
|
| + exceptions_classes = []
|
| + nb_handlers = len(node.handlers)
|
| + for index, handler in enumerate(node.handlers):
|
| + # single except doing nothing but "pass" without else clause
|
| + if is_empty(handler.body) and not node.orelse:
|
| + self.add_message('pointless-except',
|
| + node=handler.type or handler.body[0])
|
| + if handler.type is None:
|
| + if not is_raising(handler.body):
|
| + self.add_message('bare-except', node=handler)
|
| + # check if a "except:" is followed by some other
|
| + # except
|
| + if index < (nb_handlers - 1):
|
| + msg = 'empty except clause should always appear last'
|
| + self.add_message('bad-except-order', node=node, args=msg)
|
| +
|
| + elif isinstance(handler.type, astroid.BoolOp):
|
| + self.add_message('binary-op-exception',
|
| + node=handler, args=handler.type.op)
|
| + else:
|
| + try:
|
| + excs = list(_annotated_unpack_infer(handler.type))
|
| + except astroid.InferenceError:
|
| + continue
|
| + for part, exc in excs:
|
| + if exc is YES:
|
| + continue
|
| + if (isinstance(exc, astroid.Instance)
|
| + and inherit_from_std_ex(exc)):
|
| + # pylint: disable=protected-access
|
| + exc = exc._proxied
|
| +
|
| + self._check_catching_non_exception(handler, exc, part)
|
| +
|
| + if not isinstance(exc, astroid.Class):
|
| + continue
|
| +
|
| + exc_ancestors = [anc for anc in exc.ancestors()
|
| + if isinstance(anc, astroid.Class)]
|
| + for previous_exc in exceptions_classes:
|
| + if previous_exc in exc_ancestors:
|
| + msg = '%s is an ancestor class of %s' % (
|
| + previous_exc.name, exc.name)
|
| + self.add_message('bad-except-order',
|
| + node=handler.type, args=msg)
|
| + if (exc.name in self.config.overgeneral_exceptions
|
| + and exc.root().name == EXCEPTIONS_MODULE
|
| + and not is_raising(handler.body)):
|
| + self.add_message('broad-except',
|
| + args=exc.name, node=handler.type)
|
| +
|
| + exceptions_classes += [exc for _, exc in excs]
|
| +
|
| +
|
| +def register(linter):
|
| + """required method to auto register this checker"""
|
| + linter.register_checker(ExceptionsChecker(linter))
|
|
|