/pymode/libs/pylint/checkers/variables.py
Python | 1069 lines | 938 code | 38 blank | 93 comment | 49 complexity | ac5d65c35172225683215370b5a6aa03 MD5 | raw file
- # Copyright (c) 2003-2014 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.
- """variables checkers for Python code
- """
- import os
- import sys
- import re
- from copy import copy
- import astroid
- from astroid import are_exclusive, builtin_lookup
- from astroid import modutils
- from pylint.interfaces import IAstroidChecker, INFERENCE, INFERENCE_FAILURE, HIGH
- from pylint.utils import get_global_option
- from pylint.checkers import BaseChecker
- from pylint.checkers.utils import (
- PYMETHODS, is_ancestor_name, is_builtin,
- is_defined_before, is_error, is_func_default, is_func_decorator,
- assign_parent, check_messages, is_inside_except, clobber_in_except,
- get_all_elements, has_known_bases)
- import six
- SPECIAL_OBJ = re.compile("^_{2}[a-z]+_{2}$")
- PY3K = sys.version_info >= (3, 0)
- def in_for_else_branch(parent, stmt):
- """Returns True if stmt in inside the else branch for a parent For stmt."""
- return (isinstance(parent, astroid.For) and
- any(else_stmt.parent_of(stmt) for else_stmt in parent.orelse))
- def overridden_method(klass, name):
- """get overridden method if any"""
- try:
- parent = next(klass.local_attr_ancestors(name))
- except (StopIteration, KeyError):
- return None
- try:
- meth_node = parent[name]
- except KeyError:
- # We have found an ancestor defining <name> but it's not in the local
- # dictionary. This may happen with astroid built from living objects.
- return None
- if isinstance(meth_node, astroid.Function):
- return meth_node
- return None
- def _get_unpacking_extra_info(node, infered):
- """return extra information to add to the message for unpacking-non-sequence
- and unbalanced-tuple-unpacking errors
- """
- more = ''
- infered_module = infered.root().name
- if node.root().name == infered_module:
- if node.lineno == infered.lineno:
- more = ' %s' % infered.as_string()
- elif infered.lineno:
- more = ' defined at line %s' % infered.lineno
- elif infered.lineno:
- more = ' defined at line %s of %s' % (infered.lineno, infered_module)
- return more
- def _detect_global_scope(node, frame, defframe):
- """ Detect that the given frames shares a global
- scope.
- Two frames shares a global scope when neither
- of them are hidden under a function scope, as well
- as any of parent scope of them, until the root scope.
- In this case, depending from something defined later on
- will not work, because it is still undefined.
- Example:
- class A:
- # B has the same global scope as `C`, leading to a NameError.
- class B(C): ...
- class C: ...
- """
- def_scope = scope = None
- if frame and frame.parent:
- scope = frame.parent.scope()
- if defframe and defframe.parent:
- def_scope = defframe.parent.scope()
- if isinstance(frame, astroid.Function):
- # If the parent of the current node is a
- # function, then it can be under its scope
- # (defined in, which doesn't concern us) or
- # the `->` part of annotations. The same goes
- # for annotations of function arguments, they'll have
- # their parent the Arguments node.
- if not isinstance(node.parent,
- (astroid.Function, astroid.Arguments)):
- return False
- elif any(not isinstance(f, (astroid.Class, astroid.Module))
- for f in (frame, defframe)):
- # Not interested in other frames, since they are already
- # not in a global scope.
- return False
- break_scopes = []
- for s in (scope, def_scope):
- # Look for parent scopes. If there is anything different
- # than a module or a class scope, then they frames don't
- # share a global scope.
- parent_scope = s
- while parent_scope:
- if not isinstance(parent_scope, (astroid.Class, astroid.Module)):
- break_scopes.append(parent_scope)
- break
- if parent_scope.parent:
- parent_scope = parent_scope.parent.scope()
- else:
- break
- if break_scopes and len(set(break_scopes)) != 1:
- # Store different scopes than expected.
- # If the stored scopes are, in fact, the very same, then it means
- # that the two frames (frame and defframe) shares the same scope,
- # and we could apply our lineno analysis over them.
- # For instance, this works when they are inside a function, the node
- # that uses a definition and the definition itself.
- return False
- # At this point, we are certain that frame and defframe shares a scope
- # and the definition of the first depends on the second.
- return frame.lineno < defframe.lineno
- def _fix_dot_imports(not_consumed):
- """ Try to fix imports with multiple dots, by returning a dictionary
- with the import names expanded. The function unflattens root imports,
- like 'xml' (when we have both 'xml.etree' and 'xml.sax'), to 'xml.etree'
- and 'xml.sax' respectively.
- """
- # TODO: this should be improved in issue astroid #46
- names = {}
- for name, stmts in six.iteritems(not_consumed):
- if any(isinstance(stmt, astroid.AssName)
- and isinstance(stmt.ass_type(), astroid.AugAssign)
- for stmt in stmts):
- continue
- for stmt in stmts:
- if not isinstance(stmt, (astroid.From, astroid.Import)):
- continue
- for imports in stmt.names:
- second_name = None
- if imports[0] == "*":
- # In case of wildcard imports,
- # pick the name from inside the imported module.
- second_name = name
- else:
- if imports[0].find(".") > -1 or name in imports:
- # Most likely something like 'xml.etree',
- # which will appear in the .locals as 'xml'.
- # Only pick the name if it wasn't consumed.
- second_name = imports[0]
- if second_name and second_name not in names:
- names[second_name] = stmt
- return sorted(names.items(), key=lambda a: a[1].fromlineno)
- def _find_frame_imports(name, frame):
- """
- Detect imports in the frame, with the required
- *name*. Such imports can be considered assignments.
- Returns True if an import for the given name was found.
- """
- imports = frame.nodes_of_class((astroid.Import, astroid.From))
- for import_node in imports:
- for import_name, import_alias in import_node.names:
- # If the import uses an alias, check only that.
- # Otherwise, check only the import name.
- if import_alias:
- if import_alias == name:
- return True
- elif import_name and import_name == name:
- return True
- MSGS = {
- 'E0601': ('Using variable %r before assignment',
- 'used-before-assignment',
- 'Used when a local variable is accessed before it\'s \
- assignment.'),
- 'E0602': ('Undefined variable %r',
- 'undefined-variable',
- 'Used when an undefined variable is accessed.'),
- 'E0603': ('Undefined variable name %r in __all__',
- 'undefined-all-variable',
- 'Used when an undefined variable name is referenced in __all__.'),
- 'E0604': ('Invalid object %r in __all__, must contain only strings',
- 'invalid-all-object',
- 'Used when an invalid (non-string) object occurs in __all__.'),
- 'E0611': ('No name %r in module %r',
- 'no-name-in-module',
- 'Used when a name cannot be found in a module.'),
- 'W0601': ('Global variable %r undefined at the module level',
- 'global-variable-undefined',
- 'Used when a variable is defined through the "global" statement \
- but the variable is not defined in the module scope.'),
- 'W0602': ('Using global for %r but no assignment is done',
- 'global-variable-not-assigned',
- 'Used when a variable is defined through the "global" statement \
- but no assignment to this variable is done.'),
- 'W0603': ('Using the global statement', # W0121
- 'global-statement',
- 'Used when you use the "global" statement to update a global \
- variable. Pylint just try to discourage this \
- usage. That doesn\'t mean you can not use it !'),
- 'W0604': ('Using the global statement at the module level', # W0103
- 'global-at-module-level',
- 'Used when you use the "global" statement at the module level \
- since it has no effect'),
- 'W0611': ('Unused %s',
- 'unused-import',
- 'Used when an imported module or variable is not used.'),
- 'W0612': ('Unused variable %r',
- 'unused-variable',
- 'Used when a variable is defined but not used.'),
- 'W0613': ('Unused argument %r',
- 'unused-argument',
- 'Used when a function or method argument is not used.'),
- 'W0614': ('Unused import %s from wildcard import',
- 'unused-wildcard-import',
- 'Used when an imported module or variable is not used from a \
- \'from X import *\' style import.'),
- 'W0621': ('Redefining name %r from outer scope (line %s)',
- 'redefined-outer-name',
- 'Used when a variable\'s name hide a name defined in the outer \
- scope.'),
- 'W0622': ('Redefining built-in %r',
- 'redefined-builtin',
- 'Used when a variable or function override a built-in.'),
- 'W0623': ('Redefining name %r from %s in exception handler',
- 'redefine-in-handler',
- 'Used when an exception handler assigns the exception \
- to an existing name'),
- 'W0631': ('Using possibly undefined loop variable %r',
- 'undefined-loop-variable',
- 'Used when an loop variable (i.e. defined by a for loop or \
- a list comprehension or a generator expression) is used outside \
- the loop.'),
- 'W0632': ('Possible unbalanced tuple unpacking with '
- 'sequence%s: '
- 'left side has %d label(s), right side has %d value(s)',
- 'unbalanced-tuple-unpacking',
- 'Used when there is an unbalanced tuple unpacking in assignment'),
- 'W0633': ('Attempting to unpack a non-sequence%s',
- 'unpacking-non-sequence',
- 'Used when something which is not '
- 'a sequence is used in an unpack assignment'),
- 'W0640': ('Cell variable %s defined in loop',
- 'cell-var-from-loop',
- 'A variable used in a closure is defined in a loop. '
- 'This will result in all closures using the same value for '
- 'the closed-over variable.'),
- }
- class VariablesChecker(BaseChecker):
- """checks for
- * unused variables / imports
- * undefined variables
- * redefinition of variable from builtins or from an outer scope
- * use of variable before assignment
- * __all__ consistency
- """
- __implements__ = IAstroidChecker
- name = 'variables'
- msgs = MSGS
- priority = -1
- options = (("init-import",
- {'default': 0, 'type' : 'yn', 'metavar' : '<y_or_n>',
- 'help' : 'Tells whether we should check for unused import in \
- __init__ files.'}),
- ("dummy-variables-rgx",
- {'default': ('_$|dummy'),
- 'type' :'regexp', 'metavar' : '<regexp>',
- 'help' : 'A regular expression matching the name of dummy \
- variables (i.e. expectedly not used).'}),
- ("additional-builtins",
- {'default': (), 'type' : 'csv',
- 'metavar' : '<comma separated list>',
- 'help' : 'List of additional names supposed to be defined in \
- builtins. Remember that you should avoid to define new builtins when possible.'
- }),
- ("callbacks",
- {'default' : ('cb_', '_cb'), 'type' : 'csv',
- 'metavar' : '<callbacks>',
- 'help' : 'List of strings which can identify a callback '
- 'function by name. A callback name must start or '
- 'end with one of those strings.'}
- )
- )
- def __init__(self, linter=None):
- BaseChecker.__init__(self, linter)
- self._to_consume = None
- self._checking_mod_attr = None
- def visit_module(self, node):
- """visit module : update consumption analysis variable
- checks globals doesn't overrides builtins
- """
- self._to_consume = [(copy(node.locals), {}, 'module')]
- for name, stmts in six.iteritems(node.locals):
- if is_builtin(name) and not is_inside_except(stmts[0]):
- # do not print Redefining builtin for additional builtins
- self.add_message('redefined-builtin', args=name, node=stmts[0])
- @check_messages('unused-import', 'unused-wildcard-import',
- 'redefined-builtin', 'undefined-all-variable',
- 'invalid-all-object')
- def leave_module(self, node):
- """leave module: check globals
- """
- assert len(self._to_consume) == 1
- not_consumed = self._to_consume.pop()[0]
- # attempt to check for __all__ if defined
- if '__all__' in node.locals:
- assigned = next(node.igetattr('__all__'))
- if assigned is not astroid.YES:
- for elt in getattr(assigned, 'elts', ()):
- try:
- elt_name = next(elt.infer())
- except astroid.InferenceError:
- continue
- if not isinstance(elt_name, astroid.Const) \
- or not isinstance(elt_name.value, six.string_types):
- self.add_message('invalid-all-object',
- args=elt.as_string(), node=elt)
- continue
- elt_name = elt_name.value
- # If elt is in not_consumed, remove it from not_consumed
- if elt_name in not_consumed:
- del not_consumed[elt_name]
- continue
- if elt_name not in node.locals:
- if not node.package:
- self.add_message('undefined-all-variable',
- args=elt_name,
- node=elt)
- else:
- basename = os.path.splitext(node.file)[0]
- if os.path.basename(basename) == '__init__':
- name = node.name + "." + elt_name
- try:
- modutils.file_from_modpath(name.split("."))
- except ImportError:
- self.add_message('undefined-all-variable',
- args=elt_name,
- node=elt)
- except SyntaxError:
- # don't yield an syntax-error warning,
- # because it will be later yielded
- # when the file will be checked
- pass
- # don't check unused imports in __init__ files
- if not self.config.init_import and node.package:
- return
- self._check_imports(not_consumed)
- def _check_imports(self, not_consumed):
- local_names = _fix_dot_imports(not_consumed)
- checked = set()
- for name, stmt in local_names:
- for imports in stmt.names:
- real_name = imported_name = imports[0]
- if imported_name == "*":
- real_name = name
- as_name = imports[1]
- if real_name in checked:
- continue
- if name not in (real_name, as_name):
- continue
- checked.add(real_name)
- if (isinstance(stmt, astroid.Import) or
- (isinstance(stmt, astroid.From) and
- not stmt.modname)):
- if (isinstance(stmt, astroid.From) and
- SPECIAL_OBJ.search(imported_name)):
- # Filter special objects (__doc__, __all__) etc.,
- # because they can be imported for exporting.
- continue
- if as_name is None:
- msg = "import %s" % imported_name
- else:
- msg = "%s imported as %s" % (imported_name, as_name)
- self.add_message('unused-import', args=msg, node=stmt)
- elif isinstance(stmt, astroid.From) and stmt.modname != '__future__':
- if SPECIAL_OBJ.search(imported_name):
- # Filter special objects (__doc__, __all__) etc.,
- # because they can be imported for exporting.
- continue
- if imported_name == '*':
- self.add_message('unused-wildcard-import',
- args=name, node=stmt)
- else:
- if as_name is None:
- msg = "%s imported from %s" % (imported_name, stmt.modname)
- else:
- fields = (imported_name, stmt.modname, as_name)
- msg = "%s imported from %s as %s" % fields
- self.add_message('unused-import', args=msg, node=stmt)
- del self._to_consume
- def visit_class(self, node):
- """visit class: update consumption analysis variable
- """
- self._to_consume.append((copy(node.locals), {}, 'class'))
- def leave_class(self, _):
- """leave class: update consumption analysis variable
- """
- # do not check for not used locals here (no sense)
- self._to_consume.pop()
- def visit_lambda(self, node):
- """visit lambda: update consumption analysis variable
- """
- self._to_consume.append((copy(node.locals), {}, 'lambda'))
- def leave_lambda(self, _):
- """leave lambda: update consumption analysis variable
- """
- # do not check for not used locals here
- self._to_consume.pop()
- def visit_genexpr(self, node):
- """visit genexpr: update consumption analysis variable
- """
- self._to_consume.append((copy(node.locals), {}, 'comprehension'))
- def leave_genexpr(self, _):
- """leave genexpr: update consumption analysis variable
- """
- # do not check for not used locals here
- self._to_consume.pop()
- def visit_dictcomp(self, node):
- """visit dictcomp: update consumption analysis variable
- """
- self._to_consume.append((copy(node.locals), {}, 'comprehension'))
- def leave_dictcomp(self, _):
- """leave dictcomp: update consumption analysis variable
- """
- # do not check for not used locals here
- self._to_consume.pop()
- def visit_setcomp(self, node):
- """visit setcomp: update consumption analysis variable
- """
- self._to_consume.append((copy(node.locals), {}, 'comprehension'))
- def leave_setcomp(self, _):
- """leave setcomp: update consumption analysis variable
- """
- # do not check for not used locals here
- self._to_consume.pop()
- def visit_function(self, node):
- """visit function: update consumption analysis variable and check locals
- """
- self._to_consume.append((copy(node.locals), {}, 'function'))
- if not (self.linter.is_message_enabled('redefined-outer-name') or
- self.linter.is_message_enabled('redefined-builtin')):
- return
- globs = node.root().globals
- for name, stmt in node.items():
- if is_inside_except(stmt):
- continue
- if name in globs and not isinstance(stmt, astroid.Global):
- line = globs[name][0].fromlineno
- dummy_rgx = self.config.dummy_variables_rgx
- if not dummy_rgx.match(name):
- self.add_message('redefined-outer-name', args=(name, line), node=stmt)
- elif is_builtin(name):
- # do not print Redefining builtin for additional builtins
- self.add_message('redefined-builtin', args=name, node=stmt)
- def leave_function(self, node):
- """leave function: check function's locals are consumed"""
- not_consumed = self._to_consume.pop()[0]
- if not (self.linter.is_message_enabled('unused-variable') or
- self.linter.is_message_enabled('unused-argument')):
- return
- # don't check arguments of function which are only raising an exception
- if is_error(node):
- return
- # don't check arguments of abstract methods or within an interface
- is_method = node.is_method()
- klass = node.parent.frame()
- if is_method and (klass.type == 'interface' or node.is_abstract()):
- return
- if is_method and isinstance(klass, astroid.Class):
- confidence = INFERENCE if has_known_bases(klass) else INFERENCE_FAILURE
- else:
- confidence = HIGH
- authorized_rgx = self.config.dummy_variables_rgx
- called_overridden = False
- argnames = node.argnames()
- global_names = set()
- nonlocal_names = set()
- for global_stmt in node.nodes_of_class(astroid.Global):
- global_names.update(set(global_stmt.names))
- for nonlocal_stmt in node.nodes_of_class(astroid.Nonlocal):
- nonlocal_names.update(set(nonlocal_stmt.names))
- for name, stmts in six.iteritems(not_consumed):
- # ignore some special names specified by user configuration
- if authorized_rgx.match(name):
- continue
- # ignore names imported by the global statement
- # FIXME: should only ignore them if it's assigned latter
- stmt = stmts[0]
- if isinstance(stmt, astroid.Global):
- continue
- if isinstance(stmt, (astroid.Import, astroid.From)):
- # Detect imports, assigned to global statements.
- if global_names:
- skip = False
- for import_name, import_alias in stmt.names:
- # If the import uses an alias, check only that.
- # Otherwise, check only the import name.
- if import_alias:
- if import_alias in global_names:
- skip = True
- break
- elif import_name in global_names:
- skip = True
- break
- if skip:
- continue
- # care about functions with unknown argument (builtins)
- if name in argnames:
- if is_method:
- # don't warn for the first argument of a (non static) method
- if node.type != 'staticmethod' and name == argnames[0]:
- continue
- # don't warn for argument of an overridden method
- if not called_overridden:
- overridden = overridden_method(klass, node.name)
- called_overridden = True
- if overridden is not None and name in overridden.argnames():
- continue
- if node.name in PYMETHODS and node.name not in ('__init__', '__new__'):
- continue
- # don't check callback arguments
- if any(node.name.startswith(cb) or node.name.endswith(cb)
- for cb in self.config.callbacks):
- continue
- self.add_message('unused-argument', args=name, node=stmt,
- confidence=confidence)
- else:
- if stmt.parent and isinstance(stmt.parent, astroid.Assign):
- if name in nonlocal_names:
- continue
- self.add_message('unused-variable', args=name, node=stmt)
- @check_messages('global-variable-undefined', 'global-variable-not-assigned', 'global-statement',
- 'global-at-module-level', 'redefined-builtin')
- def visit_global(self, node):
- """check names imported exists in the global scope"""
- frame = node.frame()
- if isinstance(frame, astroid.Module):
- self.add_message('global-at-module-level', node=node)
- return
- module = frame.root()
- default_message = True
- for name in node.names:
- try:
- assign_nodes = module.getattr(name)
- except astroid.NotFoundError:
- # unassigned global, skip
- assign_nodes = []
- for anode in assign_nodes:
- if anode.parent is None:
- # node returned for builtin attribute such as __file__,
- # __doc__, etc...
- continue
- if anode.frame() is frame:
- # same scope level assignment
- break
- else:
- if not _find_frame_imports(name, frame):
- self.add_message('global-variable-not-assigned',
- args=name, node=node)
- default_message = False
- if not assign_nodes:
- continue
- for anode in assign_nodes:
- if anode.parent is None:
- self.add_message('redefined-builtin', args=name, node=node)
- break
- if anode.frame() is module:
- # module level assignment
- break
- else:
- # global undefined at the module scope
- self.add_message('global-variable-undefined', args=name, node=node)
- default_message = False
- if default_message:
- self.add_message('global-statement', node=node)
- def _check_late_binding_closure(self, node, assignment_node):
- def _is_direct_lambda_call():
- return (isinstance(node_scope.parent, astroid.CallFunc)
- and node_scope.parent.func is node_scope)
- node_scope = node.scope()
- if not isinstance(node_scope, (astroid.Lambda, astroid.Function)):
- return
- if isinstance(node.parent, astroid.Arguments):
- return
- if isinstance(assignment_node, astroid.Comprehension):
- if assignment_node.parent.parent_of(node.scope()):
- self.add_message('cell-var-from-loop', node=node, args=node.name)
- else:
- assign_scope = assignment_node.scope()
- maybe_for = assignment_node
- while not isinstance(maybe_for, astroid.For):
- if maybe_for is assign_scope:
- break
- maybe_for = maybe_for.parent
- else:
- if (maybe_for.parent_of(node_scope)
- and not _is_direct_lambda_call()
- and not isinstance(node_scope.statement(), astroid.Return)):
- self.add_message('cell-var-from-loop', node=node, args=node.name)
- def _loopvar_name(self, node, name):
- # filter variables according to node's scope
- # XXX used to filter parents but don't remember why, and removing this
- # fixes a W0631 false positive reported by Paul Hachmann on 2008/12 on
- # python-projects (added to func_use_for_or_listcomp_var test)
- #astmts = [stmt for stmt in node.lookup(name)[1]
- # if hasattr(stmt, 'ass_type')] and
- # not stmt.statement().parent_of(node)]
- if not self.linter.is_message_enabled('undefined-loop-variable'):
- return
- astmts = [stmt for stmt in node.lookup(name)[1]
- if hasattr(stmt, 'ass_type')]
- # filter variables according their respective scope test is_statement
- # and parent to avoid #74747. This is not a total fix, which would
- # introduce a mechanism similar to special attribute lookup in
- # modules. Also, in order to get correct inference in this case, the
- # scope lookup rules would need to be changed to return the initial
- # assignment (which does not exist in code per se) as well as any later
- # modifications.
- if not astmts or (astmts[0].is_statement or astmts[0].parent) \
- and astmts[0].statement().parent_of(node):
- _astmts = []
- else:
- _astmts = astmts[:1]
- for i, stmt in enumerate(astmts[1:]):
- if (astmts[i].statement().parent_of(stmt)
- and not in_for_else_branch(astmts[i].statement(), stmt)):
- continue
- _astmts.append(stmt)
- astmts = _astmts
- if len(astmts) == 1:
- ass = astmts[0].ass_type()
- if isinstance(ass, (astroid.For, astroid.Comprehension, astroid.GenExpr)) \
- and not ass.statement() is node.statement():
- self.add_message('undefined-loop-variable', args=name, node=node)
- @check_messages('redefine-in-handler')
- def visit_excepthandler(self, node):
- for name in get_all_elements(node.name):
- clobbering, args = clobber_in_except(name)
- if clobbering:
- self.add_message('redefine-in-handler', args=args, node=name)
- def visit_assname(self, node):
- if isinstance(node.ass_type(), astroid.AugAssign):
- self.visit_name(node)
- def visit_delname(self, node):
- self.visit_name(node)
- @check_messages(*(MSGS.keys()))
- def visit_name(self, node):
- """check that a name is defined if the current scope and doesn't
- redefine a built-in
- """
- stmt = node.statement()
- if stmt.fromlineno is None:
- # name node from a astroid built from live code, skip
- assert not stmt.root().file.endswith('.py')
- return
- name = node.name
- frame = stmt.scope()
- # if the name node is used as a function default argument's value or as
- # a decorator, then start from the parent frame of the function instead
- # of the function frame - and thus open an inner class scope
- if (is_func_default(node) or is_func_decorator(node)
- or is_ancestor_name(frame, node)):
- start_index = len(self._to_consume) - 2
- else:
- start_index = len(self._to_consume) - 1
- # iterates through parent scopes, from the inner to the outer
- base_scope_type = self._to_consume[start_index][-1]
- for i in range(start_index, -1, -1):
- to_consume, consumed, scope_type = self._to_consume[i]
- # if the current scope is a class scope but it's not the inner
- # scope, ignore it. This prevents to access this scope instead of
- # the globals one in function members when there are some common
- # names. The only exception is when the starting scope is a
- # comprehension and its direct outer scope is a class
- if scope_type == 'class' and i != start_index and not (
- base_scope_type == 'comprehension' and i == start_index-1):
- # Detect if we are in a local class scope, as an assignment.
- # For example, the following is fair game.
- #
- # class A:
- # b = 1
- # c = lambda b=b: b * b
- #
- # class B:
- # tp = 1
- # def func(self, arg: tp):
- # ...
- in_annotation = (
- PY3K and isinstance(frame, astroid.Function)
- and node.statement() is frame and
- (node in frame.args.annotations
- or node is frame.args.varargannotation
- or node is frame.args.kwargannotation))
- if in_annotation:
- frame_locals = frame.parent.scope().locals
- else:
- frame_locals = frame.locals
- if not ((isinstance(frame, astroid.Class) or in_annotation)
- and name in frame_locals):
- continue
- # the name has already been consumed, only check it's not a loop
- # variable used outside the loop
- if name in consumed:
- defnode = assign_parent(consumed[name][0])
- self._check_late_binding_closure(node, defnode)
- self._loopvar_name(node, name)
- break
- # mark the name as consumed if it's defined in this scope
- # (i.e. no KeyError is raised by "to_consume[name]")
- try:
- consumed[name] = to_consume[name]
- except KeyError:
- continue
- # checks for use before assignment
- defnode = assign_parent(to_consume[name][0])
- if defnode is not None:
- self._check_late_binding_closure(node, defnode)
- defstmt = defnode.statement()
- defframe = defstmt.frame()
- maybee0601 = True
- if not frame is defframe:
- maybee0601 = _detect_global_scope(node, frame, defframe)
- elif defframe.parent is None:
- # we are at the module level, check the name is not
- # defined in builtins
- if name in defframe.scope_attrs or builtin_lookup(name)[1]:
- maybee0601 = False
- else:
- # we are in a local scope, check the name is not
- # defined in global or builtin scope
- if defframe.root().lookup(name)[1]:
- maybee0601 = False
- else:
- # check if we have a nonlocal
- if name in defframe.locals:
- maybee0601 = not any(isinstance(child, astroid.Nonlocal)
- and name in child.names
- for child in defframe.get_children())
- # Handle a couple of class scoping issues.
- annotation_return = False
- # The class reuses itself in the class scope.
- recursive_klass = (frame is defframe and
- defframe.parent_of(node) and
- isinstance(defframe, astroid.Class) and
- node.name == defframe.name)
- if (self._to_consume[-1][-1] == 'lambda' and
- isinstance(frame, astroid.Class)
- and name in frame.locals):
- maybee0601 = True
- elif (isinstance(defframe, astroid.Class) and
- isinstance(frame, astroid.Function)):
- # Special rule for function return annotations,
- # which uses the same name as the class where
- # the function lives.
- if (PY3K and node is frame.returns and
- defframe.parent_of(frame.returns)):
- maybee0601 = annotation_return = True
- if (maybee0601 and defframe.name in defframe.locals and
- defframe.locals[name][0].lineno < frame.lineno):
- # Detect class assignments with the same
- # name as the class. In this case, no warning
- # should be raised.
- maybee0601 = False
- elif recursive_klass:
- maybee0601 = True
- else:
- maybee0601 = maybee0601 and stmt.fromlineno <= defstmt.fromlineno
- if (maybee0601
- and not is_defined_before(node)
- and not are_exclusive(stmt, defstmt, ('NameError',
- 'Exception',
- 'BaseException'))):
- if recursive_klass or (defstmt is stmt and
- isinstance(node, (astroid.DelName,
- astroid.AssName))):
- self.add_message('undefined-variable', args=name, node=node)
- elif annotation_return:
- self.add_message('undefined-variable', args=name, node=node)
- elif self._to_consume[-1][-1] != 'lambda':
- # E0601 may *not* occurs in lambda scope.
- self.add_message('used-before-assignment', args=name, node=node)
- elif self._to_consume[-1][-1] == 'lambda':
- # E0601 can occur in class-level scope in lambdas, as in
- # the following example:
- # class A:
- # x = lambda attr: f + attr
- # f = 42
- if isinstance(frame, astroid.Class) and name in frame.locals:
- if isinstance(node.parent, astroid.Arguments):
- # Doing the following is fine:
- # class A:
- # x = 42
- # y = lambda attr=x: attr
- if stmt.fromlineno <= defstmt.fromlineno:
- self.add_message('used-before-assignment',
- args=name, node=node)
- else:
- self.add_message('undefined-variable',
- args=name, node=node)
- if isinstance(node, astroid.AssName): # Aug AssName
- del consumed[name]
- else:
- del to_consume[name]
- # check it's not a loop variable used outside the loop
- self._loopvar_name(node, name)
- break
- else:
- # we have not found the name, if it isn't a builtin, that's an
- # undefined name !
- if not (name in astroid.Module.scope_attrs or is_builtin(name)
- or name in self.config.additional_builtins):
- self.add_message('undefined-variable', args=name, node=node)
- @check_messages('no-name-in-module')
- def visit_import(self, node):
- """check modules attribute accesses"""
- for name, _ in node.names:
- parts = name.split('.')
- try:
- module = next(node.infer_name_module(parts[0]))
- except astroid.ResolveError:
- continue
- self._check_module_attrs(node, module, parts[1:])
- @check_messages('no-name-in-module')
- 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 Exception: # pylint: disable=broad-except
- 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('.'))
- @check_messages('unbalanced-tuple-unpacking', 'unpacking-non-sequence')
- def visit_assign(self, node):
- """Check unbalanced tuple unpacking for assignments
- and unpacking non-sequences.
- """
- if not isinstance(node.targets[0], (astroid.Tuple, astroid.List)):
- return
- targets = node.targets[0].itered()
- try:
- for infered in node.value.infer():
- self._check_unpacking(infered, node, targets)
- except astroid.InferenceError:
- return
- def _check_unpacking(self, infered, node, targets):
- """ Check for unbalanced tuple unpacking
- and unpacking non sequences.
- """
- if infered is astroid.YES:
- return
- if (isinstance(infered.parent, astroid.Arguments) and
- isinstance(node.value, astroid.Name) and
- node.value.name == infered.parent.vararg):
- # Variable-length argument, we can't determine the length.
- return
- if isinstance(infered, (astroid.Tuple, astroid.List)):
- # attempt to check unpacking is properly balanced
- values = infered.itered()
- if len(targets) != len(values):
- # Check if we have starred nodes.
- if any(isinstance(target, astroid.Starred)
- for target in targets):
- return
- self.add_message('unbalanced-tuple-unpacking', node=node,
- args=(_get_unpacking_extra_info(node, infered),
- len(targets),
- len(values)))
- # attempt to check unpacking may be possible (ie RHS is iterable)
- elif isinstance(infered, astroid.Instance):
- for meth in ('__iter__', '__getitem__'):
- try:
- infered.getattr(meth)
- break
- except astroid.NotFoundError:
- continue
- else:
- self.add_message('unpacking-non-sequence', node=node,
- args=(_get_unpacking_extra_info(node, infered),))
- else:
- self.add_message('unpacking-non-sequence', node=node,
- args=(_get_unpacking_extra_info(node, infered),))
- 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, astroid.Module), module
- ignored_modules = get_global_option(self, 'ignored-modules',
- default=[])
- while module_names:
- name = module_names.pop(0)
- if name == '__dict__':
- module = None
- break
- try:
- module = next(module.getattr(name)[0].infer())
- if module is astroid.YES:
- return None
- except astroid.NotFoundError:
- if module.name in ignored_modules:
- return None
- self.add_message('no-name-in-module',
- args=(name, module.name), node=node)
- return None
- except astroid.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('no-name-in-module', node=node,
- args=('.'.join(module_names), modname))
- return None
- if isinstance(module, astroid.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()
- def leave_module(self, node):
- """ Update consumption analysis variable
- for metaclasses.
- """
- module_locals = self._to_consume[0][0]
- module_imports = self._to_consume[0][1]
- consumed = {}
- for klass in node.nodes_of_class(astroid.Class):
- found = metaclass = name = None
- if not klass._metaclass:
- # Skip if this class doesn't use
- # explictly a metaclass, but inherits it from ancestors
- continue
- metaclass = klass.metaclass()
- # Look the name in the already found locals.
- # If it's not found there, look in the module locals
- # and in the imported modules.
- if isinstance(klass._metaclass, astroid.Name):
- name = klass._metaclass.name
- elif metaclass:
- # if it uses a `metaclass=module.Class`
- name = metaclass.root().name
- if name:
- found = consumed.setdefault(
- name, module_locals.get(name, module_imports.get(name)))
- if found is None and not metaclass:
- name = None
- if isinstance(klass._metaclass, astroid.Name):
- name = klass._metaclass.name
- elif isinstance(klass._metaclass, astroid.Getattr):
- name = klass._metaclass.as_string()
- if name is not None:
- if not (name in astroid.Module.scope_attrs or
- is_builtin(name) or
- name in self.config.additional_builtins or
- name in node.locals):
- self.add_message('undefined-variable',
- node=klass,
- args=(name, ))
- # Pop the consumed items, in order to
- # avoid having unused-import false positives
- for name in consumed:
- module_locals.pop(name, None)
- super(VariablesChecker3k, self).leave_module(node)
- if sys.version_info >= (3, 0):
- VariablesChecker = VariablesChecker3k
- def register(linter):
- """required method to auto register this checker"""
- linter.register_checker(VariablesChecker(linter))