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550 lines
23 KiB
Python
550 lines
23 KiB
Python
# Copyright (c) 2003-2011 LOGILAB S.A. (Paris, FRANCE).
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# http://www.logilab.fr/ -- mailto:contact@logilab.fr
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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"""variables checkers for Python code
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"""
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import sys
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from copy import copy
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from logilab import astng
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from logilab.astng import are_exclusive, builtin_lookup, ASTNGBuildingException
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from pylint.interfaces import IASTNGChecker
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from pylint.checkers import BaseChecker
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from pylint.checkers.utils import (PYMETHODS, is_ancestor_name, is_builtin,
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is_defined_before, is_error, is_func_default, is_func_decorator,
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assign_parent, check_messages, is_inside_except, clobber_in_except)
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def in_for_else_branch(parent, stmt):
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"""Returns True if stmt in inside the else branch for a parent For stmt."""
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return (isinstance(parent, astng.For) and
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any(else_stmt.parent_of(stmt) for else_stmt in parent.orelse))
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def overridden_method(klass, name):
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"""get overridden method if any"""
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try:
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parent = klass.local_attr_ancestors(name).next()
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except (StopIteration, KeyError):
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return None
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try:
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meth_node = parent[name]
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except KeyError:
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# We have found an ancestor defining <name> but it's not in the local
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# dictionary. This may happen with astng built from living objects.
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return None
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if isinstance(meth_node, astng.Function):
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return meth_node
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return None
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MSGS = {
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'E0601': ('Using variable %r before assignment',
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'Used when a local variable is accessed before it\'s \
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assignment.'),
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'E0602': ('Undefined variable %r',
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'Used when an undefined variable is accessed.'),
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'E0611': ('No name %r in module %r',
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'Used when a name cannot be found in a module.'),
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'W0601': ('Global variable %r undefined at the module level',
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'Used when a variable is defined through the "global" statement \
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but the variable is not defined in the module scope.'),
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'W0602': ('Using global for %r but no assignment is done',
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'Used when a variable is defined through the "global" statement \
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but no assignment to this variable is done.'),
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'W0603': ('Using the global statement', # W0121
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'Used when you use the "global" statement to update a global \
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variable. PyLint just try to discourage this \
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usage. That doesn\'t mean you can not use it !'),
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'W0604': ('Using the global statement at the module level', # W0103
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'Used when you use the "global" statement at the module level \
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since it has no effect'),
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'W0611': ('Unused import %s',
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'Used when an imported module or variable is not used.'),
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'W0612': ('Unused variable %r',
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'Used when a variable is defined but not used.'),
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'W0613': ('Unused argument %r',
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'Used when a function or method argument is not used.'),
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'W0614': ('Unused import %s from wildcard import',
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'Used when an imported module or variable is not used from a \
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\'from X import *\' style import.'),
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'W0621': ('Redefining name %r from outer scope (line %s)',
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'Used when a variable\'s name hide a name defined in the outer \
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scope.'),
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'W0622': ('Redefining built-in %r',
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'Used when a variable or function override a built-in.'),
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'W0623': ('Redefining name %r from %s in exception handler',
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'Used when an exception handler assigns the exception \
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to an existing name'),
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'W0631': ('Using possibly undefined loop variable %r',
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'Used when an loop variable (i.e. defined by a for loop or \
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a list comprehension or a generator expression) is used outside \
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the loop.'),
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}
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class VariablesChecker(BaseChecker):
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"""checks for
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* unused variables / imports
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* undefined variables
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* redefinition of variable from builtins or from an outer scope
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* use of variable before assignment
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"""
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__implements__ = IASTNGChecker
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name = 'variables'
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msgs = MSGS
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priority = -1
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options = (
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("init-import",
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{'default': 0, 'type' : 'yn', 'metavar' : '<y_or_n>',
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'help' : 'Tells whether we should check for unused import in \
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__init__ files.'}),
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("dummy-variables-rgx",
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{'default': ('_|dummy'),
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'type' :'regexp', 'metavar' : '<regexp>',
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'help' : 'A regular expression matching the beginning of \
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the name of dummy variables (i.e. not used).'}),
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("additional-builtins",
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{'default': (), 'type' : 'csv',
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'metavar' : '<comma separated list>',
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'help' : 'List of additional names supposed to be defined in \
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builtins. Remember that you should avoid to define new builtins when possible.'
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}),
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)
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def __init__(self, linter=None):
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BaseChecker.__init__(self, linter)
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self._to_consume = None
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self._checking_mod_attr = None
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self._vars = None
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def visit_module(self, node):
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"""visit module : update consumption analysis variable
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checks globals doesn't overrides builtins
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"""
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self._to_consume = [(copy(node.locals), {}, 'module')]
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self._vars = []
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for name, stmts in node.locals.items():
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if is_builtin(name) and not is_inside_except(stmts[0]):
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# do not print Redefining builtin for additional builtins
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self.add_message('W0622', args=name, node=stmts[0])
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@check_messages('W0611', 'W0614')
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def leave_module(self, node):
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"""leave module: check globals
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"""
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assert len(self._to_consume) == 1
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not_consumed = self._to_consume.pop()[0]
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# don't check unused imports in __init__ files
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if not self.config.init_import and node.package:
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return
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for name, stmts in not_consumed.items():
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stmt = stmts[0]
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if isinstance(stmt, astng.Import):
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self.add_message('W0611', args=name, node=stmt)
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elif isinstance(stmt, astng.From) and stmt.modname != '__future__':
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if stmt.names[0][0] == '*':
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self.add_message('W0614', args=name, node=stmt)
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else:
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self.add_message('W0611', args=name, node=stmt)
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del self._to_consume
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del self._vars
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def visit_class(self, node):
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"""visit class: update consumption analysis variable
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"""
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self._to_consume.append((copy(node.locals), {}, 'class'))
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def leave_class(self, _):
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"""leave class: update consumption analysis variable
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"""
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# do not check for not used locals here (no sense)
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self._to_consume.pop()
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def visit_lambda(self, node):
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"""visit lambda: update consumption analysis variable
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"""
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self._to_consume.append((copy(node.locals), {}, 'lambda'))
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def leave_lambda(self, _):
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"""leave lambda: update consumption analysis variable
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"""
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# do not check for not used locals here
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self._to_consume.pop()
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def visit_genexpr(self, node):
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"""visit genexpr: update consumption analysis variable
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"""
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self._to_consume.append((copy(node.locals), {}, 'comprehension'))
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def leave_genexpr(self, _):
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"""leave genexpr: update consumption analysis variable
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"""
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# do not check for not used locals here
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self._to_consume.pop()
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def visit_dictcomp(self, node):
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"""visit dictcomp: update consumption analysis variable
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"""
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self._to_consume.append((copy(node.locals), {}, 'comprehension'))
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def leave_dictcomp(self, _):
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"""leave dictcomp: update consumption analysis variable
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"""
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# do not check for not used locals here
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self._to_consume.pop()
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def visit_setcomp(self, node):
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"""visit setcomp: update consumption analysis variable
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"""
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self._to_consume.append((copy(node.locals), {}, 'comprehension'))
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def leave_setcomp(self, _):
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"""leave setcomp: update consumption analysis variable
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"""
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# do not check for not used locals here
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self._to_consume.pop()
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def visit_function(self, node):
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"""visit function: update consumption analysis variable and check locals
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"""
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self._to_consume.append((copy(node.locals), {}, 'function'))
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self._vars.append({})
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if not set(('W0621', 'W0622')) & self.active_msgs:
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return
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globs = node.root().globals
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for name, stmt in node.items():
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if is_inside_except(stmt):
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continue
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if name in globs and not isinstance(stmt, astng.Global):
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line = globs[name][0].lineno
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self.add_message('W0621', args=(name, line), node=stmt)
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elif is_builtin(name):
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# do not print Redefining builtin for additional builtins
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self.add_message('W0622', args=name, node=stmt)
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def leave_function(self, node):
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"""leave function: check function's locals are consumed"""
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not_consumed = self._to_consume.pop()[0]
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self._vars.pop(0)
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if not set(('W0612', 'W0613')) & self.active_msgs:
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return
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# don't check arguments of function which are only raising an exception
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if is_error(node):
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return
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# don't check arguments of abstract methods or within an interface
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is_method = node.is_method()
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klass = node.parent.frame()
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if is_method and (klass.type == 'interface' or node.is_abstract()):
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return
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authorized_rgx = self.config.dummy_variables_rgx
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called_overridden = False
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argnames = node.argnames()
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for name, stmts in not_consumed.iteritems():
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# ignore some special names specified by user configuration
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if authorized_rgx.match(name):
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continue
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# ignore names imported by the global statement
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# FIXME: should only ignore them if it's assigned latter
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stmt = stmts[0]
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if isinstance(stmt, astng.Global):
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continue
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# care about functions with unknown argument (builtins)
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if name in argnames:
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if is_method:
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# don't warn for the first argument of a (non static) method
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if node.type != 'staticmethod' and name == argnames[0]:
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continue
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# don't warn for argument of an overridden method
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if not called_overridden:
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overridden = overridden_method(klass, node.name)
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called_overridden = True
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if overridden is not None and name in overridden.argnames():
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continue
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if node.name in PYMETHODS and node.name not in ('__init__', '__new__'):
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continue
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# don't check callback arguments XXX should be configurable
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if node.name.startswith('cb_') or node.name.endswith('_cb'):
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continue
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self.add_message('W0613', args=name, node=stmt)
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else:
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self.add_message('W0612', args=name, node=stmt)
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@check_messages('W0601', 'W0602', 'W0603', 'W0604', 'W0622')
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def visit_global(self, node):
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"""check names imported exists in the global scope"""
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frame = node.frame()
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if isinstance(frame, astng.Module):
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self.add_message('W0604', node=node)
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return
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module = frame.root()
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default_message = True
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for name in node.names:
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try:
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assign_nodes = module.getattr(name)
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except astng.NotFoundError:
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# unassigned global, skip
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assign_nodes = []
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for anode in assign_nodes:
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if anode.parent is None:
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# node returned for builtin attribute such as __file__,
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# __doc__, etc...
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continue
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if anode.frame() is frame:
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# same scope level assignment
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break
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else:
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# global but no assignment
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self.add_message('W0602', args=name, node=node)
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default_message = False
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if not assign_nodes:
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continue
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for anode in assign_nodes:
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if anode.parent is None:
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self.add_message('W0622', args=name, node=node)
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break
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if anode.frame() is module:
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# module level assignment
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break
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else:
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# global undefined at the module scope
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self.add_message('W0601', args=name, node=node)
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default_message = False
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if default_message:
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self.add_message('W0603', node=node)
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def _loopvar_name(self, node, name):
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# filter variables according to node's scope
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# XXX used to filter parents but don't remember why, and removing this
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# fixes a W0631 false positive reported by Paul Hachmann on 2008/12 on
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# python-projects (added to func_use_for_or_listcomp_var test)
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#astmts = [stmt for stmt in node.lookup(name)[1]
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# if hasattr(stmt, 'ass_type')] and
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# not stmt.statement().parent_of(node)]
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if 'W0631' not in self.active_msgs:
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return
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astmts = [stmt for stmt in node.lookup(name)[1]
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if hasattr(stmt, 'ass_type')]
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# filter variables according their respective scope test is_statement
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# and parent to avoid #74747. This is not a total fix, which would
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# introduce a mechanism similar to special attribute lookup in
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# modules. Also, in order to get correct inference in this case, the
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# scope lookup rules would need to be changed to return the initial
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# assignment (which does not exist in code per se) as well as any later
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# modifications.
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if not astmts or (astmts[0].is_statement or astmts[0].parent) \
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and astmts[0].statement().parent_of(node):
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_astmts = []
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else:
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_astmts = astmts[:1]
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for i, stmt in enumerate(astmts[1:]):
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if (astmts[i].statement().parent_of(stmt)
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and not in_for_else_branch(astmts[i].statement(), stmt)):
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continue
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_astmts.append(stmt)
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astmts = _astmts
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if len(astmts) == 1:
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ass = astmts[0].ass_type()
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if isinstance(ass, (astng.For, astng.Comprehension, astng.GenExpr)) \
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and not ass.statement() is node.statement():
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self.add_message('W0631', args=name, node=node)
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def visit_excepthandler(self, node):
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clobbering, args = clobber_in_except(node.name)
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if clobbering:
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self.add_message('W0623', args=args, node=node)
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def visit_assname(self, node):
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if isinstance(node.ass_type(), astng.AugAssign):
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self.visit_name(node)
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def visit_delname(self, node):
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self.visit_name(node)
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def visit_name(self, node):
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"""check that a name is defined if the current scope and doesn't
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redefine a built-in
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"""
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stmt = node.statement()
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if stmt.fromlineno is None:
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# name node from a astng built from live code, skip
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assert not stmt.root().file.endswith('.py')
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return
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name = node.name
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frame = stmt.scope()
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# if the name node is used as a function default argument's value or as
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# a decorator, then start from the parent frame of the function instead
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# of the function frame - and thus open an inner class scope
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if (is_func_default(node) or is_func_decorator(node)
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or is_ancestor_name(frame, node)):
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start_index = len(self._to_consume) - 2
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else:
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start_index = len(self._to_consume) - 1
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# iterates through parent scopes, from the inner to the outer
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base_scope_type = self._to_consume[start_index][-1]
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for i in range(start_index, -1, -1):
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to_consume, consumed, scope_type = self._to_consume[i]
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# if the current scope is a class scope but it's not the inner
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# scope, ignore it. This prevents to access this scope instead of
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# the globals one in function members when there are some common
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# names. The only exception is when the starting scope is a
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# comprehension and its direct outer scope is a class
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if scope_type == 'class' and i != start_index and not (
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base_scope_type == 'comprehension' and i == start_index-1):
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# XXX find a way to handle class scope in a smoother way
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continue
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# the name has already been consumed, only check it's not a loop
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# variable used outside the loop
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if name in consumed:
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self._loopvar_name(node, name)
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break
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# mark the name as consumed if it's defined in this scope
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# (i.e. no KeyError is raised by "to_consume[name]")
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try:
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consumed[name] = to_consume[name]
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except KeyError:
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continue
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# checks for use before assignment
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defnode = assign_parent(to_consume[name][0])
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if defnode is not None:
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defstmt = defnode.statement()
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defframe = defstmt.frame()
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maybee0601 = True
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if not frame is defframe:
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maybee0601 = False
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elif defframe.parent is None:
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# we are at the module level, check the name is not
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# defined in builtins
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if name in defframe.scope_attrs or builtin_lookup(name)[1]:
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maybee0601 = False
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else:
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# we are in a local scope, check the name is not
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# defined in global or builtin scope
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if defframe.root().lookup(name)[1]:
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maybee0601 = False
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if (maybee0601
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and stmt.fromlineno <= defstmt.fromlineno
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and not is_defined_before(node)
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and not are_exclusive(stmt, defstmt, ('NameError', 'Exception', 'BaseException'))):
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if defstmt is stmt and isinstance(node, (astng.DelName,
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astng.AssName)):
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self.add_message('E0602', args=name, node=node)
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elif self._to_consume[-1][-1] != 'lambda':
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# E0601 may *not* occurs in lambda scope
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self.add_message('E0601', args=name, node=node)
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if not isinstance(node, astng.AssName): # Aug AssName
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del to_consume[name]
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else:
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del consumed[name]
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# check it's not a loop variable used outside the loop
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self._loopvar_name(node, name)
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break
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else:
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# we have not found the name, if it isn't a builtin, that's an
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# undefined name !
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if not (name in astng.Module.scope_attrs or is_builtin(name)
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or name in self.config.additional_builtins):
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self.add_message('E0602', args=name, node=node)
|
|
|
|
@check_messages('E0611')
|
|
def visit_import(self, node):
|
|
"""check modules attribute accesses"""
|
|
for name, _ in node.names:
|
|
parts = name.split('.')
|
|
try:
|
|
module = node.infer_name_module(parts[0]).next()
|
|
except astng.ResolveError:
|
|
continue
|
|
self._check_module_attrs(node, module, parts[1:])
|
|
|
|
@check_messages('E0611')
|
|
def visit_from(self, node):
|
|
"""check modules attribute accesses"""
|
|
name_parts = node.modname.split('.')
|
|
level = getattr(node, 'level', None)
|
|
try:
|
|
module = node.root().import_module(name_parts[0], level=level)
|
|
except ASTNGBuildingException:
|
|
return
|
|
except Exception, exc:
|
|
print 'Unhandled exception in VariablesChecker:', exc
|
|
return
|
|
module = self._check_module_attrs(node, module, name_parts[1:])
|
|
if not module:
|
|
return
|
|
for name, _ in node.names:
|
|
if name == '*':
|
|
continue
|
|
self._check_module_attrs(node, module, name.split('.'))
|
|
|
|
def _check_module_attrs(self, node, module, module_names):
|
|
"""check that module_names (list of string) are accessible through the
|
|
given module
|
|
if the latest access name corresponds to a module, return it
|
|
"""
|
|
assert isinstance(module, astng.Module), module
|
|
while module_names:
|
|
name = module_names.pop(0)
|
|
if name == '__dict__':
|
|
module = None
|
|
break
|
|
try:
|
|
module = module.getattr(name)[0].infer().next()
|
|
if module is astng.YES:
|
|
return None
|
|
except astng.NotFoundError:
|
|
self.add_message('E0611', args=(name, module.name), node=node)
|
|
return None
|
|
except astng.InferenceError:
|
|
return None
|
|
if module_names:
|
|
# FIXME: other message if name is not the latest part of
|
|
# module_names ?
|
|
modname = module and module.name or '__dict__'
|
|
self.add_message('E0611', node=node,
|
|
args=('.'.join(module_names), modname))
|
|
return None
|
|
if isinstance(module, astng.Module):
|
|
return module
|
|
return None
|
|
|
|
|
|
class VariablesChecker3k(VariablesChecker):
|
|
'''Modified variables checker for 3k'''
|
|
# listcomp have now also their scope
|
|
|
|
def visit_listcomp(self, node):
|
|
"""visit dictcomp: update consumption analysis variable
|
|
"""
|
|
self._to_consume.append((copy(node.locals), {}, 'comprehension'))
|
|
|
|
def leave_listcomp(self, _):
|
|
"""leave dictcomp: update consumption analysis variable
|
|
"""
|
|
# do not check for not used locals here
|
|
self._to_consume.pop()
|
|
|
|
if sys.version_info >= (3, 0):
|
|
VariablesChecker = VariablesChecker3k
|
|
|
|
|
|
def register(linter):
|
|
"""required method to auto register this checker"""
|
|
linter.register_checker(VariablesChecker(linter))
|