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Diffstat (limited to 'checkers/exceptions.py')
| -rw-r--r-- | checkers/exceptions.py | 286 |
1 files changed, 0 insertions, 286 deletions
diff --git a/checkers/exceptions.py b/checkers/exceptions.py deleted file mode 100644 index 30b3fa8..0000000 --- a/checkers/exceptions.py +++ /dev/null @@ -1,286 +0,0 @@ -# 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 - -from logilab.common.compat import builtins -BUILTINS_NAME = builtins.__name__ -import astroid -from astroid import YES, Instance, unpack_infer - -from pylint.checkers import BaseChecker -from pylint.checkers.utils import is_empty, is_raising, check_messages -from pylint.interfaces import IAstroidChecker - -def infer_bases(klass): - """ Fully infer the bases of the klass node. - - This doesn't use .ancestors(), because we need - the non-inferable nodes (YES nodes), - which can't be retrieved from .ancestors() - """ - for base in klass.bases: - try: - inferit = base.infer().next() - except astroid.InferenceError: - continue - if inferit is YES: - yield inferit - else: - for base in infer_bases(inferit): - yield base - -PY3K = sys.version_info >= (3, 0) -OVERGENERAL_EXCEPTIONS = ('Exception',) - -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, instances or string 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.'), - - 'W0701': ('Raising a string exception', - 'raising-string', - 'Used when a string exception is raised.'), - '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.'), - '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):"'), - 'W0712': ('Implicit unpacking of exceptions is not supported in Python 3', - 'unpacking-in-except', - 'Python3 will not allow implicit unpacking of exceptions in except ' - 'clauses. ' - 'See http://www.python.org/dev/peps/pep-3110/', - {'maxversion': (3, 0)}), - } - - -if sys.version_info < (3, 0): - EXCEPTIONS_MODULE = "exceptions" -else: - EXCEPTIONS_MODULE = "builtins" - -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('raising-string', '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: - try: - cause = node.cause.infer().next() - except astroid.InferenceError: - pass - else: - 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) - expr = node.exc - if self._check_raise_value(node, expr): - return - else: - try: - value = unpack_infer(expr).next() - except astroid.InferenceError: - return - self._check_raise_value(node, value) - - 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 isinstance(value, str): - self.add_message('raising-string', node=node) - else: - 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)): - 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, astroid.BinOp) and expr.op == '%': - self.add_message('raising-string', node=node) - elif isinstance(expr, (Instance, astroid.Class)): - if isinstance(expr, Instance): - expr = expr._proxied - if (isinstance(expr, astroid.Class) and - not inherit_from_std_ex(expr) and - expr.root().name != BUILTINS_NAME): - if expr.newstyle: - self.add_message('raising-non-exception', node=node) - else: - self.add_message('nonstandard-exception', node=node) - else: - value_found = False - else: - value_found = False - return value_found - - @check_messages('unpacking-in-except') - def visit_excepthandler(self, node): - """Visit an except handler block and check for exception unpacking.""" - if isinstance(node.name, (astroid.Tuple, astroid.List)): - self.add_message('unpacking-in-except', node=node) - - - @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 nb_handlers == 1 and 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 nb_handlers == 1 and not is_raising(handler.body): - self.add_message('bare-except', node=handler) - # check if a "except:" is followed by some other - # except - elif 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(unpack_infer(handler.type)) - except astroid.InferenceError: - continue - for exc in excs: - # XXX skip other non class nodes - if exc is YES or 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 nb_handlers == 1 and not is_raising(handler.body)): - self.add_message('broad-except', args=exc.name, node=handler.type) - - if (not inherit_from_std_ex(exc) and - exc.root().name != BUILTINS_NAME): - # try to see if the exception is based on a C based - # exception, by infering all the base classes and - # looking for inference errors - bases = infer_bases(exc) - fully_infered = all(inferit is not YES - for inferit in bases) - if fully_infered: - self.add_message('catching-non-exception', - node=handler.type, - args=(exc.name, )) - - exceptions_classes += excs - - -def inherit_from_std_ex(node): - """return true if the given class node is subclass of - exceptions.Exception - """ - if node.name in ('Exception', 'BaseException') \ - and node.root().name == EXCEPTIONS_MODULE: - return True - for parent in node.ancestors(recurs=False): - if inherit_from_std_ex(parent): - return True - return False - -def register(linter): - """required method to auto register this checker""" - linter.register_checker(ExceptionsChecker(linter)) |