82 lines
3.2 KiB
Python
82 lines
3.2 KiB
Python
# -*- coding: utf-8 -*-
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# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
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"""Looks for overlapping exceptions."""
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import astroid
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from pylint import interfaces
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from pylint import checkers
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from pylint.checkers import utils
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from pylint.checkers.exceptions import _annotated_unpack_infer
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class OverlappingExceptionsChecker(checkers.BaseChecker):
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"""Checks for two or more exceptions in the same exception handler
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clause that are identical or parts of the same inheritance hierarchy
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(i.e. overlapping)."""
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__implements__ = interfaces.IAstroidChecker
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name = 'overlap-except'
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msgs = {'W0714': ('Overlapping exceptions (%s)',
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'overlapping-except',
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'Used when exceptions in handler overlap or are identical')}
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priority = -2
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options = ()
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@utils.check_messages('overlapping-except')
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def visit_tryexcept(self, node):
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"""check for empty except"""
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for handler in node.handlers:
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if handler.type is None:
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continue
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if isinstance(handler.type, astroid.BoolOp):
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continue
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try:
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excs = list(_annotated_unpack_infer(handler.type))
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except astroid.InferenceError:
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continue
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handled_in_clause = []
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for part, exc in excs:
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if exc is astroid.YES:
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continue
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if (isinstance(exc, astroid.Instance) and
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utils.inherit_from_std_ex(exc)):
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# pylint: disable=protected-access
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exc = exc._proxied
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if not isinstance(exc, astroid.ClassDef):
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continue
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exc_ancestors = [anc for anc in exc.ancestors()
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if isinstance(anc, astroid.ClassDef)]
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for prev_part, prev_exc in handled_in_clause:
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prev_exc_ancestors = [anc for anc in prev_exc.ancestors()
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if isinstance(anc, astroid.ClassDef)]
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if exc == prev_exc:
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self.add_message('overlapping-except',
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node=handler.type,
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args='%s and %s are the same' %
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(prev_part.as_string(),
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part.as_string()))
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elif (prev_exc in exc_ancestors or
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exc in prev_exc_ancestors):
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ancestor = part if exc in prev_exc_ancestors else prev_part
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descendant = part if prev_exc in exc_ancestors else prev_part
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self.add_message('overlapping-except',
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node=handler.type,
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args='%s is an ancestor class of %s' %
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(ancestor.as_string(), descendant.as_string()))
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handled_in_clause += [(part, exc)]
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def register(linter):
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"""Required method to auto register this checker."""
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linter.register_checker(OverlappingExceptionsChecker(linter))
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