# Copyright (c) 2006-2014 LOGILAB S.A. (Paris, FRANCE) # Copyright (c) 2009 Mads Kiilerich # Copyright (c) 2010 Daniel Harding # Copyright (c) 2011-2014, 2017 Google, Inc. # Copyright (c) 2012 FELD Boris # Copyright (c) 2013-2020 Claudiu Popa # Copyright (c) 2014 Michal Nowikowski # Copyright (c) 2014 Brett Cannon # Copyright (c) 2014 Ricardo Gemignani # Copyright (c) 2014 Arun Persaud # Copyright (c) 2015 Dmitry Pribysh # Copyright (c) 2015 Radu Ciorba # Copyright (c) 2015 Simu Toni # Copyright (c) 2015 Ionel Cristian Maries # Copyright (c) 2016, 2018-2019 Ashley Whetter # Copyright (c) 2016, 2018 Jakub Wilk # Copyright (c) 2016-2017 Derek Gustafson # Copyright (c) 2016-2017 Łukasz Rogalski # Copyright (c) 2016 Grant Welch # Copyright (c) 2017-2018, 2020 hippo91 # Copyright (c) 2017-2018 Ville Skyttä # Copyright (c) 2017 Dan Garrette # Copyright (c) 2018-2019 Jim Robertson # Copyright (c) 2018 Mike Miller # Copyright (c) 2018 Lucas Cimon # Copyright (c) 2018 Drew # Copyright (c) 2018 Sushobhit <31987769+sushobhit27@users.noreply.github.com> # Copyright (c) 2018 ssolanki # Copyright (c) 2018 Bryce Guinta # Copyright (c) 2018 Bryce Guinta # Copyright (c) 2018 Mike Frysinger # Copyright (c) 2018 Marianna Polatoglou # Copyright (c) 2018 mar-chi-pan # Copyright (c) 2019-2021 Pierre Sassoulas # Copyright (c) 2019 Nick Drozd # Copyright (c) 2019 Djailla # Copyright (c) 2019 Hugo van Kemenade # Copyright (c) 2020 Andrew Simmons # Copyright (c) 2020 Andrew Simmons # Copyright (c) 2020 Anthony Sottile # Copyright (c) 2020 Ashley Whetter # Copyright (c) 2021 Daniël van Noord <13665637+DanielNoord@users.noreply.github.com> # Copyright (c) 2021 Marc Mueller <30130371+cdce8p@users.noreply.github.com> # Copyright (c) 2021 David Liu # Copyright (c) 2021 kasium <15907922+kasium@users.noreply.github.com> # Copyright (c) 2021 Marcin Kurczewski # Copyright (c) 2021 Sergei Lebedev <185856+superbobry@users.noreply.github.com> # Copyright (c) 2021 Lorena B <46202743+lorena-b@users.noreply.github.com> # Copyright (c) 2021 haasea <44787650+haasea@users.noreply.github.com> # Copyright (c) 2021 Alexander Kapshuna # Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE """variables checkers for Python code """ import collections import copy import itertools import os import re from functools import lru_cache import astroid from astroid import nodes from pylint.checkers import BaseChecker, utils from pylint.checkers.utils import is_postponed_evaluation_enabled from pylint.constants import PY39_PLUS from pylint.interfaces import HIGH, INFERENCE, INFERENCE_FAILURE, IAstroidChecker from pylint.utils import get_global_option SPECIAL_OBJ = re.compile("^_{2}[a-z]+_{2}$") FUTURE = "__future__" # regexp for ignored argument name IGNORED_ARGUMENT_NAMES = re.compile("_.*|^ignored_|^unused_") # In Python 3.7 abc has a Python implementation which is preferred # by astroid. Unfortunately this also messes up our explicit checks # for `abc` METACLASS_NAME_TRANSFORMS = {"_py_abc": "abc"} TYPING_TYPE_CHECKS_GUARDS = frozenset({"typing.TYPE_CHECKING", "TYPE_CHECKING"}) BUILTIN_RANGE = "builtins.range" TYPING_MODULE = "typing" TYPING_NAMES = frozenset( { "Any", "Callable", "ClassVar", "Generic", "Optional", "Tuple", "Type", "TypeVar", "Union", "AbstractSet", "ByteString", "Container", "ContextManager", "Hashable", "ItemsView", "Iterable", "Iterator", "KeysView", "Mapping", "MappingView", "MutableMapping", "MutableSequence", "MutableSet", "Sequence", "Sized", "ValuesView", "Awaitable", "AsyncIterator", "AsyncIterable", "Coroutine", "Collection", "AsyncGenerator", "AsyncContextManager", "Reversible", "SupportsAbs", "SupportsBytes", "SupportsComplex", "SupportsFloat", "SupportsInt", "SupportsRound", "Counter", "Deque", "Dict", "DefaultDict", "List", "Set", "FrozenSet", "NamedTuple", "Generator", "AnyStr", "Text", "Pattern", "BinaryIO", } ) def _is_from_future_import(stmt, name): """Check if the name is a future import from another module.""" try: module = stmt.do_import_module(stmt.modname) except astroid.AstroidBuildingException: return None for local_node in module.locals.get(name, []): if isinstance(local_node, nodes.ImportFrom) and local_node.modname == FUTURE: return True return None def in_for_else_branch(parent, stmt): """Returns True if stmt in inside the else branch for a parent For stmt.""" return isinstance(parent, nodes.For) and any( else_stmt.parent_of(stmt) or else_stmt == stmt for else_stmt in parent.orelse ) @lru_cache(maxsize=1000) 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 but it's not in the local # dictionary. This may happen with astroid built from living objects. return None if isinstance(meth_node, nodes.FunctionDef): return meth_node return None def _get_unpacking_extra_info(node, inferred): """return extra information to add to the message for unpacking-non-sequence and unbalanced-tuple-unpacking errors """ more = "" inferred_module = inferred.root().name if node.root().name == inferred_module: if node.lineno == inferred.lineno: more = f" {inferred.as_string()}" elif inferred.lineno: more = f" defined at line {inferred.lineno}" elif inferred.lineno: more = f" defined at line {inferred.lineno} of {inferred_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, nodes.FunctionDef): # 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, (nodes.FunctionDef, nodes.Arguments)): return False elif any( not isinstance(f, (nodes.ClassDef, nodes.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 current_scope 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 = current_scope while parent_scope: if not isinstance(parent_scope, (nodes.ClassDef, nodes.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 _infer_name_module(node, name): context = astroid.context.InferenceContext() context.lookupname = name return node.infer(context, asname=False) 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. """ names = {} for name, stmts in not_consumed.items(): if any( isinstance(stmt, nodes.AssignName) and isinstance(stmt.assign_type(), nodes.AugAssign) for stmt in stmts ): continue for stmt in stmts: if not isinstance(stmt, (nodes.ImportFrom, nodes.Import)): continue for imports in stmt.names: second_name = None import_module_name = imports[0] if import_module_name == "*": # In case of wildcard imports, # pick the name from inside the imported module. second_name = name else: name_matches_dotted_import = False if ( import_module_name.startswith(name) and import_module_name.find(".") > -1 ): name_matches_dotted_import = True if name_matches_dotted_import 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 = import_module_name 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((nodes.Import, nodes.ImportFrom)) 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 return None def _import_name_is_global(stmt, global_names): 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: return True elif import_name in global_names: return True return False def _flattened_scope_names(iterator): values = (set(stmt.names) for stmt in iterator) return set(itertools.chain.from_iterable(values)) def _assigned_locally(name_node): """ Checks if name_node has corresponding assign statement in same scope """ assign_stmts = name_node.scope().nodes_of_class(nodes.AssignName) return any(a.name == name_node.name for a in assign_stmts) def _is_type_checking_import(node): parent = node.parent if not isinstance(parent, nodes.If): return False test = parent.test return test.as_string() in TYPING_TYPE_CHECKS_GUARDS def _has_locals_call_after_node(stmt, scope): skip_nodes = ( nodes.FunctionDef, nodes.ClassDef, nodes.Import, nodes.ImportFrom, ) for call in scope.nodes_of_class(nodes.Call, skip_klass=skip_nodes): inferred = utils.safe_infer(call.func) if ( utils.is_builtin_object(inferred) and getattr(inferred, "name", None) == "locals" ): if stmt.lineno < call.lineno: return True return False MSGS = { "E0601": ( "Using variable %r before assignment", "used-before-assignment", "Used when a local variable is accessed before its 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__.", ), "E0605": ( "Invalid format for __all__, must be tuple or list", "invalid-all-format", "Used when __all__ has an invalid format.", ), "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 cannot 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 hides a name defined in the outer scope.", ), "W0622": ( "Redefining built-in %r", "redefined-builtin", "Used when a variable or function override a built-in.", ), "W0631": ( "Using possibly undefined loop variable %r", "undefined-loop-variable", "Used when a 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", {"old_names": [("E0632", "old-unbalanced-tuple-unpacking")]}, ), "E0633": ( "Attempting to unpack a non-sequence%s", "unpacking-non-sequence", "Used when something which is not " "a sequence is used in an unpack assignment", {"old_names": [("W0633", "old-unpacking-non-sequence")]}, ), "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.", ), "W0641": ( "Possibly unused variable %r", "possibly-unused-variable", "Used when a variable is defined but might not be used. " "The possibility comes from the fact that locals() might be used, " "which could consume or not the said variable", ), "W0642": ( "Invalid assignment to %s in method", "self-cls-assignment", "Invalid assignment to self or cls in instance or class method " "respectively.", ), } ScopeConsumer = collections.namedtuple( "ScopeConsumer", "to_consume consumed scope_type" ) class NamesConsumer: """ A simple class to handle consumed, to consume and scope type info of node locals """ def __init__(self, node, scope_type): self._atomic = ScopeConsumer(copy.copy(node.locals), {}, scope_type) self.node = node def __repr__(self): to_consumes = [f"{k}->{v}" for k, v in self._atomic.to_consume.items()] consumed = [f"{k}->{v}" for k, v in self._atomic.consumed.items()] to_consumes = ", ".join(to_consumes) consumed = ", ".join(consumed) return f""" to_consume : {to_consumes} consumed : {consumed} scope_type : {self._atomic.scope_type} """ def __iter__(self): return iter(self._atomic) @property def to_consume(self): return self._atomic.to_consume @property def consumed(self): return self._atomic.consumed @property def scope_type(self): return self._atomic.scope_type def mark_as_consumed(self, name, consumed_nodes): """ Mark the given nodes as consumed for the name. If all of the nodes for the name were consumed, delete the name from the to_consume dictionary """ unconsumed = [n for n in self.to_consume[name] if n not in set(consumed_nodes)] self.consumed[name] = consumed_nodes if unconsumed: self.to_consume[name] = unconsumed else: del self.to_consume[name] def get_next_to_consume(self, node): """ Return a list of the nodes that define `node` from this scope. Return None to indicate a special case that needs to be handled by the caller. """ name = node.name parent_node = node.parent found_nodes = self.to_consume.get(name) if ( found_nodes and isinstance(parent_node, nodes.Assign) and parent_node == found_nodes[0].parent ): lhs = found_nodes[0].parent.targets[0] if lhs.name == name: # this name is defined in this very statement found_nodes = None if ( found_nodes and isinstance(parent_node, nodes.For) and parent_node.iter == node and parent_node.target in found_nodes ): found_nodes = None # Filter out assignments in ExceptHandlers that node is not contained in if found_nodes: found_nodes = [ n for n in found_nodes if not isinstance(n.statement(), nodes.ExceptHandler) or n.statement().parent_of(node) ] return found_nodes # pylint: disable=too-many-public-methods 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 * self/cls assignment """ __implements__ = IAstroidChecker name = "variables" msgs = MSGS priority = -1 options = ( ( "init-import", { "default": 0, "type": "yn", "metavar": "", "help": "Tells whether we should check for unused import in " "__init__ files.", }, ), ( "dummy-variables-rgx", { "default": "_+$|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)|dummy|^ignored_|^unused_", "type": "regexp", "metavar": "", "help": "A regular expression matching the name of dummy " "variables (i.e. expected to not be used).", }, ), ( "additional-builtins", { "default": (), "type": "csv", "metavar": "", "help": "List of additional names supposed to be defined in " "builtins. Remember that you should avoid defining new builtins " "when possible.", }, ), ( "callbacks", { "default": ("cb_", "_cb"), "type": "csv", "metavar": "", "help": "List of strings which can identify a callback " "function by name. A callback name must start or " "end with one of those strings.", }, ), ( "redefining-builtins-modules", { "default": ( "six.moves", "past.builtins", "future.builtins", "builtins", "io", ), "type": "csv", "metavar": "", "help": "List of qualified module names which can have objects " "that can redefine builtins.", }, ), ( "ignored-argument-names", { "default": IGNORED_ARGUMENT_NAMES, "type": "regexp", "metavar": "", "help": "Argument names that match this expression will be " "ignored. Default to name with leading underscore.", }, ), ( "allow-global-unused-variables", { "default": True, "type": "yn", "metavar": "", "help": "Tells whether unused global variables should be treated as a violation.", }, ), ( "allowed-redefined-builtins", { "default": (), "type": "csv", "metavar": "", "help": "List of names allowed to shadow builtins", }, ), ) def __init__(self, linter=None): BaseChecker.__init__(self, linter) self._to_consume = ( None # list of tuples: (to_consume:dict, consumed:dict, scope_type:str) ) self._checking_mod_attr = None self._loop_variables = [] self._type_annotation_names = [] self._postponed_evaluation_enabled = False @utils.check_messages("redefined-outer-name") def visit_for(self, node: nodes.For) -> None: assigned_to = [a.name for a in node.target.nodes_of_class(nodes.AssignName)] # Only check variables that are used dummy_rgx = self.config.dummy_variables_rgx assigned_to = [var for var in assigned_to if not dummy_rgx.match(var)] for variable in assigned_to: for outer_for, outer_variables in self._loop_variables: if variable in outer_variables and not in_for_else_branch( outer_for, node ): self.add_message( "redefined-outer-name", args=(variable, outer_for.fromlineno), node=node, ) break self._loop_variables.append((node, assigned_to)) @utils.check_messages("redefined-outer-name") def leave_for(self, node: nodes.For) -> None: self._loop_variables.pop() self._store_type_annotation_names(node) def visit_module(self, node: nodes.Module) -> None: """visit module : update consumption analysis variable checks globals doesn't overrides builtins """ self._to_consume = [NamesConsumer(node, "module")] self._postponed_evaluation_enabled = is_postponed_evaluation_enabled(node) for name, stmts in node.locals.items(): if utils.is_builtin(name): if self._should_ignore_redefined_builtin(stmts[0]) or name == "__doc__": continue self.add_message("redefined-builtin", args=name, node=stmts[0]) @utils.check_messages( "unused-import", "unused-wildcard-import", "redefined-builtin", "undefined-all-variable", "invalid-all-object", "invalid-all-format", "unused-variable", ) def leave_module(self, node: nodes.Module) -> None: """leave module: check globals""" assert len(self._to_consume) == 1 self._check_metaclasses(node) not_consumed = self._to_consume.pop().to_consume # attempt to check for __all__ if defined if "__all__" in node.locals: self._check_all(node, not_consumed) # check for unused globals self._check_globals(not_consumed) # don't check unused imports in __init__ files if not self.config.init_import and node.package: return self._check_imports(not_consumed) def visit_classdef(self, node: nodes.ClassDef) -> None: """visit class: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "class")) def leave_classdef(self, _: nodes.ClassDef) -> None: """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: nodes.Lambda) -> None: """visit lambda: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "lambda")) def leave_lambda(self, _: nodes.Lambda) -> None: """leave lambda: update consumption analysis variable""" # do not check for not used locals here self._to_consume.pop() def visit_generatorexp(self, node: nodes.GeneratorExp) -> None: """visit genexpr: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "comprehension")) def leave_generatorexp(self, _: nodes.GeneratorExp) -> None: """leave genexpr: update consumption analysis variable""" # do not check for not used locals here self._to_consume.pop() def visit_dictcomp(self, node: nodes.DictComp) -> None: """visit dictcomp: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "comprehension")) def leave_dictcomp(self, _: nodes.DictComp) -> None: """leave dictcomp: update consumption analysis variable""" # do not check for not used locals here self._to_consume.pop() def visit_setcomp(self, node: nodes.SetComp) -> None: """visit setcomp: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "comprehension")) def leave_setcomp(self, _: nodes.SetComp) -> None: """leave setcomp: update consumption analysis variable""" # do not check for not used locals here self._to_consume.pop() def visit_functiondef(self, node: nodes.FunctionDef) -> None: """visit function: update consumption analysis variable and check locals""" self._to_consume.append(NamesConsumer(node, "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 name in globs and not isinstance(stmt, nodes.Global): definition = globs[name][0] if ( isinstance(definition, nodes.ImportFrom) and definition.modname == FUTURE ): # It is a __future__ directive, not a symbol. continue # Do not take in account redefined names for the purpose # of type checking.: if any( isinstance(definition.parent, nodes.If) and definition.parent.test.as_string() in TYPING_TYPE_CHECKS_GUARDS for definition in globs[name] ): continue line = definition.fromlineno if not self._is_name_ignored(stmt, name): self.add_message( "redefined-outer-name", args=(name, line), node=stmt ) elif ( utils.is_builtin(name) and not self._allowed_redefined_builtin(name) and not self._should_ignore_redefined_builtin(stmt) ): # do not print Redefining builtin for additional builtins self.add_message("redefined-builtin", args=name, node=stmt) def leave_functiondef(self, node: nodes.FunctionDef) -> None: """leave function: check function's locals are consumed""" self._check_metaclasses(node) if node.type_comment_returns: self._store_type_annotation_node(node.type_comment_returns) if node.type_comment_args: for argument_annotation in node.type_comment_args: self._store_type_annotation_node(argument_annotation) not_consumed = self._to_consume.pop().to_consume if not ( self.linter.is_message_enabled("unused-variable") or self.linter.is_message_enabled("possibly-unused-variable") or self.linter.is_message_enabled("unused-argument") ): return # Don't check arguments of function which are only raising an exception. if utils.is_error(node): return # Don't check arguments of abstract methods or within an interface. is_method = node.is_method() if is_method and node.is_abstract(): return global_names = _flattened_scope_names(node.nodes_of_class(nodes.Global)) nonlocal_names = _flattened_scope_names(node.nodes_of_class(nodes.Nonlocal)) for name, stmts in not_consumed.items(): self._check_is_unused(name, node, stmts[0], global_names, nonlocal_names) visit_asyncfunctiondef = visit_functiondef leave_asyncfunctiondef = leave_functiondef @utils.check_messages( "global-variable-undefined", "global-variable-not-assigned", "global-statement", "global-at-module-level", "redefined-builtin", ) def visit_global(self, node: nodes.Global) -> None: """check names imported exists in the global scope""" frame = node.frame() if isinstance(frame, nodes.Module): self.add_message("global-at-module-level", node=node) return module = frame.root() default_message = True locals_ = node.scope().locals for name in node.names: try: assign_nodes = module.getattr(name) except astroid.NotFoundError: # unassigned global, skip assign_nodes = [] not_defined_locally_by_import = not any( isinstance(local, nodes.Import) for local in locals_.get(name, ()) ) if ( not utils.is_reassigned_after_current(node, name) and not_defined_locally_by_import ): self.add_message("global-variable-not-assigned", args=name, node=node) default_message = False continue for anode in assign_nodes: if ( isinstance(anode, nodes.AssignName) and anode.name in module.special_attributes ): self.add_message("redefined-builtin", args=name, node=node) break if anode.frame() is module: # module level assignment break if isinstance(anode, nodes.FunctionDef) and anode.parent is module: # module level function assignment break else: if not_defined_locally_by_import: # 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 visit_assignname(self, node: nodes.AssignName) -> None: if isinstance(node.assign_type(), nodes.AugAssign): self.visit_name(node) def visit_delname(self, node: nodes.DelName) -> None: self.visit_name(node) # pylint: disable=too-many-branches def visit_name(self, node: nodes.Name) -> None: """Check that a name is defined in the current scope""" stmt = node.statement() if stmt.fromlineno is None: # name node from an astroid built from live code, skip assert not stmt.root().file.endswith(".py") return name = node.name frame = stmt.scope() start_index = len(self._to_consume) - 1 undefined_variable_is_enabled = self.linter.is_message_enabled( "undefined-variable" ) used_before_assignment_is_enabled = self.linter.is_message_enabled( "used-before-assignment" ) # iterates through parent scopes, from the inner to the outer base_scope_type = self._to_consume[start_index].scope_type # pylint: disable=too-many-nested-blocks; refactoring this block is a pain. for i in range(start_index, -1, -1): current_consumer = self._to_consume[i] # The list of base classes in the class definition is not part # of the class body. # 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. if current_consumer.scope_type == "class" and ( utils.is_ancestor_name(current_consumer.node, node) or (i != start_index and self._ignore_class_scope(node)) ): continue # Ignore inner class scope for keywords in class definition if ( current_consumer.scope_type == "class" and isinstance(node.parent, nodes.Keyword) and isinstance(node.parent.parent, nodes.ClassDef) ): continue # 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 ( current_consumer.scope_type == "function" and self._defined_in_function_definition(node, current_consumer.node) ): # ignore function scope if is an annotation/default/decorator, as not in the body continue if current_consumer.scope_type == "lambda" and utils.is_default_argument( node, current_consumer.node ): continue # the name has already been consumed, only check it's not a loop # variable used outside the loop # avoid the case where there are homonyms inside function scope and # comprehension current scope (avoid bug #1731) if name in current_consumer.consumed and ( utils.is_func_decorator(current_consumer.node) or not ( current_consumer.scope_type == "comprehension" and self._has_homonym_in_upper_function_scope(node, i) ) ): self._check_late_binding_closure(node) self._loopvar_name(node, name) break found_nodes = current_consumer.get_next_to_consume(node) if found_nodes is None: continue # checks for use before assignment if found_nodes: defnode = utils.assign_parent(found_nodes[0]) else: defnode = None if used_before_assignment_is_enabled: self.add_message("used-before-assignment", args=name, node=node) self._check_late_binding_closure(node) if ( undefined_variable_is_enabled or used_before_assignment_is_enabled ) and defnode is not None: defstmt = defnode.statement() defframe = defstmt.frame() # The class reuses itself in the class scope. recursive_klass = ( frame is defframe and defframe.parent_of(node) and isinstance(defframe, nodes.ClassDef) and node.name == defframe.name ) if ( recursive_klass and utils.is_inside_lambda(node) and ( not utils.is_default_argument(node) or node.scope().parent.scope() is not defframe ) ): # Self-referential class references are fine in lambda's -- # As long as they are not part of the default argument directly # under the scope of the parent self-referring class. # Example of valid default argument: # class MyName3: # myattr = 1 # mylambda3 = lambda: lambda a=MyName3: a # Example of invalid default argument: # class MyName4: # myattr = 1 # mylambda4 = lambda a=MyName4: lambda: a # If the above conditional is True, # there is no possibility of undefined-variable # Also do not consume class name # (since consuming blocks subsequent checks) # -- quit break ( maybee0601, annotation_return, use_outer_definition, ) = self._is_variable_violation( node, name, defnode, stmt, defstmt, frame, defframe, base_scope_type, recursive_klass, ) if use_outer_definition: continue if ( maybee0601 and not utils.is_defined_before(node) and not astroid.are_exclusive(stmt, defstmt, ("NameError",)) ): # Used and defined in the same place, e.g `x += 1` and `del x` defined_by_stmt = defstmt is stmt and isinstance( node, (nodes.DelName, nodes.AssignName) ) if ( recursive_klass or defined_by_stmt or annotation_return or isinstance(defstmt, nodes.Delete) ): if not utils.node_ignores_exception(node, NameError): # Handle postponed evaluation of annotations if not ( self._postponed_evaluation_enabled and isinstance( stmt, ( nodes.AnnAssign, nodes.FunctionDef, nodes.Arguments, ), ) and name in node.root().locals ): self.add_message( "undefined-variable", args=name, node=node ) elif base_scope_type != "lambda": # E0601 may *not* occurs in lambda scope. # Handle postponed evaluation of annotations if not ( self._postponed_evaluation_enabled and isinstance(stmt, (nodes.AnnAssign, nodes.FunctionDef)) ): self.add_message( "used-before-assignment", args=name, node=node ) elif base_scope_type == "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, nodes.ClassDef) and name in frame.locals: if isinstance(node.parent, nodes.Arguments): if stmt.fromlineno <= defstmt.fromlineno: # Doing the following is fine: # class A: # x = 42 # y = lambda attr=x: attr self.add_message( "used-before-assignment", args=name, node=node ) else: self.add_message( "undefined-variable", args=name, node=node ) elif current_consumer.scope_type == "lambda": self.add_message("undefined-variable", node=node, args=name) current_consumer.mark_as_consumed(name, found_nodes) # 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 undefined_variable_is_enabled and not ( name in nodes.Module.scope_attrs or utils.is_builtin(name) or name in self.config.additional_builtins or ( name == "__class__" and isinstance(frame, nodes.FunctionDef) and frame.is_method() ) ): if not utils.node_ignores_exception(node, NameError): self.add_message("undefined-variable", args=name, node=node) @utils.check_messages("no-name-in-module") def visit_import(self, node: nodes.Import) -> None: """check modules attribute accesses""" if not self._analyse_fallback_blocks and utils.is_from_fallback_block(node): # No need to verify this, since ImportError is already # handled by the client code. return if utils.is_node_in_guarded_import_block(node) is True: # Don't verify import if part of guarded import block # I.e. `sys.version_info` or `typing.TYPE_CHECKING` return for name, _ in node.names: parts = name.split(".") try: module = next(_infer_name_module(node, parts[0])) except astroid.ResolveError: continue if not isinstance(module, nodes.Module): continue self._check_module_attrs(node, module, parts[1:]) @utils.check_messages("no-name-in-module") def visit_importfrom(self, node: nodes.ImportFrom) -> None: """check modules attribute accesses""" if not self._analyse_fallback_blocks and utils.is_from_fallback_block(node): # No need to verify this, since ImportError is already # handled by the client code. return if utils.is_node_in_guarded_import_block(node) is True: # Don't verify import if part of guarded import block # I.e. `sys.version_info` or `typing.TYPE_CHECKING` return name_parts = node.modname.split(".") try: module = node.do_import_module(name_parts[0]) except astroid.AstroidBuildingException: 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(".")) @utils.check_messages( "unbalanced-tuple-unpacking", "unpacking-non-sequence", "self-cls-assignment" ) def visit_assign(self, node: nodes.Assign) -> None: """Check unbalanced tuple unpacking for assignments and unpacking non-sequences as well as in case self/cls get assigned. """ self._check_self_cls_assign(node) if not isinstance(node.targets[0], (nodes.Tuple, nodes.List)): return targets = node.targets[0].itered() try: inferred = utils.safe_infer(node.value) if inferred is not None: self._check_unpacking(inferred, node, targets) except astroid.InferenceError: return # listcomp have now also their scope def visit_listcomp(self, node: nodes.ListComp) -> None: """visit dictcomp: update consumption analysis variable""" self._to_consume.append(NamesConsumer(node, "comprehension")) def leave_listcomp(self, _: nodes.ListComp) -> None: """leave dictcomp: update consumption analysis variable""" # do not check for not used locals here self._to_consume.pop() def leave_assign(self, node: nodes.Assign) -> None: self._store_type_annotation_names(node) def leave_with(self, node: nodes.With) -> None: self._store_type_annotation_names(node) def visit_arguments(self, node: nodes.Arguments) -> None: for annotation in node.type_comment_args: self._store_type_annotation_node(annotation) # Relying on other checker's options, which might not have been initialized yet. @astroid.decorators.cachedproperty def _analyse_fallback_blocks(self): return get_global_option(self, "analyse-fallback-blocks", default=False) @astroid.decorators.cachedproperty def _ignored_modules(self): return get_global_option(self, "ignored-modules", default=[]) @astroid.decorators.cachedproperty def _allow_global_unused_variables(self): return get_global_option(self, "allow-global-unused-variables", default=True) @staticmethod def _defined_in_function_definition(node, frame): in_annotation_or_default_or_decorator = False if isinstance(frame, nodes.FunctionDef) and node.statement() is frame: in_annotation_or_default_or_decorator = ( ( node in frame.args.annotations or node in frame.args.posonlyargs_annotations or node in frame.args.kwonlyargs_annotations or node is frame.args.varargannotation or node is frame.args.kwargannotation ) or frame.args.parent_of(node) or (frame.decorators and frame.decorators.parent_of(node)) or ( frame.returns and (node is frame.returns or frame.returns.parent_of(node)) ) ) return in_annotation_or_default_or_decorator @staticmethod def _in_lambda_or_comprehension_body( node: nodes.NodeNG, frame: nodes.NodeNG ) -> bool: """return True if node within a lambda/comprehension body (or similar) and thus should not have access to class attributes in frame""" child = node parent = node.parent while parent is not None: if parent is frame: return False if isinstance(parent, nodes.Lambda) and child is not parent.args: # Body of lambda should not have access to class attributes. return True if isinstance(parent, nodes.Comprehension) and child is not parent.iter: # Only iter of list/set/dict/generator comprehension should have access. return True if isinstance(parent, nodes.ComprehensionScope) and not ( parent.generators and child is parent.generators[0] ): # Body of list/set/dict/generator comprehension should not have access to class attributes. # Furthermore, only the first generator (if multiple) in comprehension should have access. return True child = parent parent = parent.parent return False @staticmethod def _is_variable_violation( node, name, defnode, stmt, defstmt, frame, defframe, base_scope_type, recursive_klass, ): # pylint: disable=too-many-nested-blocks # node: Node to check for violation # name: name of node to check violation for # frame: Scope of statement of node # base_scope_type: local scope type maybee0601 = True annotation_return = False use_outer_definition = False if frame is not 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 astroid.builtin_lookup(name)[1]: maybee0601 = False else: # we are in a local scope, check the name is not # defined in global or builtin scope # skip this lookup if name is assigned later in function scope/lambda # Note: the node.frame() is not the same as the `frame` argument which is # equivalent to frame.statement().scope() forbid_lookup = ( isinstance(frame, nodes.FunctionDef) or isinstance(node.frame(), nodes.Lambda) ) and _assigned_locally(node) if not forbid_lookup and defframe.root().lookup(name)[1]: maybee0601 = False use_outer_definition = stmt == defstmt and not isinstance( defnode, nodes.Comprehension ) # check if we have a nonlocal elif name in defframe.locals: maybee0601 = not any( isinstance(child, nodes.Nonlocal) and name in child.names for child in defframe.get_children() ) if ( base_scope_type == "lambda" and isinstance(frame, nodes.ClassDef) and name in frame.locals ): # This rule verifies that if the definition node of the # checked name is an Arguments node and if the name # is used a default value in the arguments defaults # and the actual definition of the variable label # is happening before the Arguments definition. # # bar = None # foo = lambda bar=bar: bar # # In this case, maybee0601 should be False, otherwise # it should be True. maybee0601 = not ( isinstance(defnode, nodes.Arguments) and node in defnode.defaults and frame.locals[name][0].fromlineno < defstmt.fromlineno ) elif isinstance(defframe, nodes.ClassDef) and isinstance( frame, nodes.FunctionDef ): # Special rule for function return annotations, # which uses the same name as the class where # the function lives. if 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 if isinstance(node.parent, nodes.Arguments): maybee0601 = stmt.fromlineno <= defstmt.fromlineno elif recursive_klass: maybee0601 = True else: maybee0601 = maybee0601 and stmt.fromlineno <= defstmt.fromlineno if maybee0601 and stmt.fromlineno == defstmt.fromlineno: if ( isinstance(defframe, nodes.FunctionDef) and frame is defframe and defframe.parent_of(node) and stmt is not defstmt ): # Single statement function, with the statement on the # same line as the function definition maybee0601 = False elif ( isinstance( defstmt, ( nodes.Assign, nodes.AnnAssign, nodes.AugAssign, nodes.Expr, nodes.Return, ), ) and isinstance(defstmt.value, nodes.IfExp) and frame is defframe and defframe.parent_of(node) and stmt is defstmt ): # Single statement if, with assingment expression on same # line as assigment # x = b if (b := True) else False maybee0601 = False elif ( isinstance( # pylint: disable=too-many-boolean-expressions defnode, nodes.NamedExpr ) and frame is defframe and defframe.parent_of(stmt) and stmt is defstmt and ( ( defnode.lineno == node.lineno and defnode.col_offset < node.col_offset ) or (defnode.lineno < node.lineno) or ( # Issue in the `ast` module until py39 # Nodes in a multiline string have the same lineno # Could be false-positive without check not PY39_PLUS and defnode.lineno == node.lineno and isinstance( defstmt, ( nodes.Assign, nodes.AnnAssign, nodes.AugAssign, nodes.Return, ), ) and isinstance(defstmt.value, nodes.JoinedStr) ) ) ): # Expressions, with assignment expressions # Use only after assignment # b = (c := 2) and c maybee0601 = False # Look for type checking definitions inside a type checking guard. if isinstance(defstmt, (nodes.Import, nodes.ImportFrom)): defstmt_parent = defstmt.parent if ( isinstance(defstmt_parent, nodes.If) and defstmt_parent.test.as_string() in TYPING_TYPE_CHECKS_GUARDS ): # Exempt those definitions that are used inside the type checking # guard or that are defined in both type checking guard branches. used_in_branch = defstmt_parent.parent_of(node) defined_in_or_else = False for definition in defstmt_parent.orelse: if isinstance(definition, nodes.Assign): defined_in_or_else = any( target.name == name for target in definition.targets ) if defined_in_or_else: break if not used_in_branch and not defined_in_or_else: maybee0601 = True return maybee0601, annotation_return, use_outer_definition def _ignore_class_scope(self, node): """ Return True if the node is in a local class scope, as an assignment. :param node: Node considered :type node: astroid.Node :return: True if the node is in a local class scope, as an assignment. False otherwise. :rtype: bool """ # 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): # ... # class C: # tp = 2 # def func(self, arg=tp): # ... # class C: # class Tp: # pass # class D(Tp): # ... name = node.name frame = node.statement().scope() in_annotation_or_default_or_decorator = self._defined_in_function_definition( node, frame ) in_ancestor_list = utils.is_ancestor_name(frame, node) if in_annotation_or_default_or_decorator or in_ancestor_list: frame_locals = frame.parent.scope().locals else: frame_locals = frame.locals return not ( (isinstance(frame, nodes.ClassDef) or in_annotation_or_default_or_decorator) and not self._in_lambda_or_comprehension_body(node, frame) and name in frame_locals ) def _loopvar_name(self, node, name): # filter variables according to node's scope if not self.linter.is_message_enabled("undefined-loop-variable"): return astmts = [stmt for stmt in node.lookup(name)[1] if hasattr(stmt, "assign_type")] # If this variable usage exists inside a function definition # that exists in the same loop, # the usage is safe because the function will not be defined either if # the variable is not defined. scope = node.scope() if isinstance(scope, nodes.FunctionDef) and any( asmt.statement().parent_of(scope) for asmt in astmts ): return # 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: return assign = astmts[0].assign_type() if not ( isinstance(assign, (nodes.For, nodes.Comprehension, nodes.GeneratorExp)) and assign.statement() is not node.statement() ): return # For functions we can do more by inferring the length of the itered object if not isinstance(assign, nodes.For): self.add_message("undefined-loop-variable", args=name, node=node) return try: inferred = next(assign.iter.infer()) except astroid.InferenceError: self.add_message("undefined-loop-variable", args=name, node=node) else: if ( isinstance(inferred, astroid.Instance) and inferred.qname() == BUILTIN_RANGE ): # Consider range() objects safe, even if they might not yield any results. return # Consider sequences. sequences = ( nodes.List, nodes.Tuple, nodes.Dict, nodes.Set, astroid.objects.FrozenSet, ) if not isinstance(inferred, sequences): self.add_message("undefined-loop-variable", args=name, node=node) return elements = getattr(inferred, "elts", getattr(inferred, "items", [])) if not elements: self.add_message("undefined-loop-variable", args=name, node=node) def _check_is_unused(self, name, node, stmt, global_names, nonlocal_names): # pylint: disable=too-many-branches # Ignore some special names specified by user configuration. if self._is_name_ignored(stmt, name): return # Ignore names that were added dynamically to the Function scope if ( isinstance(node, nodes.FunctionDef) and name == "__class__" and len(node.locals["__class__"]) == 1 and isinstance(node.locals["__class__"][0], nodes.ClassDef) ): return # Ignore names imported by the global statement. if isinstance(stmt, (nodes.Global, nodes.Import, nodes.ImportFrom)): # Detect imports, assigned to global statements. if global_names and _import_name_is_global(stmt, global_names): return argnames = list( itertools.chain(node.argnames(), [arg.name for arg in node.args.kwonlyargs]) ) # Care about functions with unknown argument (builtins) if name in argnames: self._check_unused_arguments(name, node, stmt, argnames) else: if stmt.parent and isinstance(stmt.parent, (nodes.Assign, nodes.AnnAssign)): if name in nonlocal_names: return qname = asname = None if isinstance(stmt, (nodes.Import, nodes.ImportFrom)): # Need the complete name, which we don't have in .locals. if len(stmt.names) > 1: import_names = next( (names for names in stmt.names if name in names), None ) else: import_names = stmt.names[0] if import_names: qname, asname = import_names name = asname or qname if _has_locals_call_after_node(stmt, node.scope()): message_name = "possibly-unused-variable" else: if isinstance(stmt, nodes.Import): if asname is not None: msg = f"{qname} imported as {asname}" else: msg = f"import {name}" self.add_message("unused-import", args=msg, node=stmt) return if isinstance(stmt, nodes.ImportFrom): if asname is not None: msg = f"{qname} imported from {stmt.modname} as {asname}" else: msg = f"{name} imported from {stmt.modname}" self.add_message("unused-import", args=msg, node=stmt) return message_name = "unused-variable" if isinstance(stmt, nodes.FunctionDef) and stmt.decorators: return # Don't check function stubs created only for type information if utils.is_overload_stub(node): return # Special case for exception variable if isinstance(stmt.parent, nodes.ExceptHandler) and any( n.name == name for n in stmt.parent.nodes_of_class(nodes.Name) ): return self.add_message(message_name, args=name, node=stmt) def _is_name_ignored(self, stmt, name): authorized_rgx = self.config.dummy_variables_rgx if ( isinstance(stmt, nodes.AssignName) and isinstance(stmt.parent, nodes.Arguments) or isinstance(stmt, nodes.Arguments) ): regex = self.config.ignored_argument_names else: regex = authorized_rgx return regex and regex.match(name) def _check_unused_arguments(self, name, node, stmt, argnames): is_method = node.is_method() klass = node.parent.frame() if is_method and isinstance(klass, nodes.ClassDef): confidence = ( INFERENCE if utils.has_known_bases(klass) else INFERENCE_FAILURE ) else: confidence = HIGH if is_method: # Don't warn for the first argument of a (non static) method if node.type != "staticmethod" and name == argnames[0]: return # Don't warn for argument of an overridden method overridden = overridden_method(klass, node.name) if overridden is not None and name in overridden.argnames(): return if node.name in utils.PYMETHODS and node.name not in ( "__init__", "__new__", ): return # Don't check callback arguments if any( node.name.startswith(cb) or node.name.endswith(cb) for cb in self.config.callbacks ): return # Don't check arguments of singledispatch.register function. if utils.is_registered_in_singledispatch_function(node): return # Don't check function stubs created only for type information if utils.is_overload_stub(node): return # Don't check protocol classes if utils.is_protocol_class(klass): return self.add_message("unused-argument", args=name, node=stmt, confidence=confidence) def _check_late_binding_closure(self, node: nodes.Name) -> None: """Check whether node is a cell var that is assigned within a containing loop. Special cases where we don't care about the error: 1. When the node's function is immediately called, e.g. (lambda: i)() 2. When the node's function is returned from within the loop, e.g. return lambda: i """ if not self.linter.is_message_enabled("cell-var-from-loop"): return node_scope = node.frame() # If node appears in a default argument expression, # look at the next enclosing frame instead if utils.is_default_argument(node, node_scope): node_scope = node_scope.parent.frame() # Check if node is a cell var if ( not isinstance(node_scope, (nodes.Lambda, nodes.FunctionDef)) or node.name in node_scope.locals ): return assign_scope, stmts = node.lookup(node.name) if not stmts or not assign_scope.parent_of(node_scope): return if utils.is_comprehension(assign_scope): self.add_message("cell-var-from-loop", node=node, args=node.name) else: # Look for an enclosing For loop. # Currently, we only consider the first assignment assignment_node = stmts[0] maybe_for = assignment_node while maybe_for and not isinstance(maybe_for, nodes.For): if maybe_for is assign_scope: break maybe_for = maybe_for.parent else: if ( maybe_for and maybe_for.parent_of(node_scope) and not utils.is_being_called(node_scope) and not isinstance(node_scope.statement(), nodes.Return) ): self.add_message("cell-var-from-loop", node=node, args=node.name) def _should_ignore_redefined_builtin(self, stmt): if not isinstance(stmt, nodes.ImportFrom): return False return stmt.modname in self.config.redefining_builtins_modules def _allowed_redefined_builtin(self, name): return name in self.config.allowed_redefined_builtins def _has_homonym_in_upper_function_scope(self, node, index): """ Return True if there is a node with the same name in the to_consume dict of an upper scope and if that scope is a function :param node: node to check for :type node: astroid.Node :param index: index of the current consumer inside self._to_consume :type index: int :return: True if there is a node with the same name in the to_consume dict of an upper scope and if that scope is a function :rtype: bool """ for _consumer in self._to_consume[index - 1 :: -1]: if _consumer.scope_type == "function" and node.name in _consumer.to_consume: return True return False def _store_type_annotation_node(self, type_annotation): """Given a type annotation, store all the name nodes it refers to""" if isinstance(type_annotation, nodes.Name): self._type_annotation_names.append(type_annotation.name) return if isinstance(type_annotation, nodes.Attribute): self._store_type_annotation_node(type_annotation.expr) return if not isinstance(type_annotation, nodes.Subscript): return if ( isinstance(type_annotation.value, nodes.Attribute) and isinstance(type_annotation.value.expr, nodes.Name) and type_annotation.value.expr.name == TYPING_MODULE ): self._type_annotation_names.append(TYPING_MODULE) return self._type_annotation_names.extend( annotation.name for annotation in type_annotation.nodes_of_class(nodes.Name) ) def _store_type_annotation_names(self, node): type_annotation = node.type_annotation if not type_annotation: return self._store_type_annotation_node(node.type_annotation) def _check_self_cls_assign(self, node): """Check that self/cls don't get assigned""" assign_names = { target.name for target in node.targets if isinstance(target, nodes.AssignName) } scope = node.scope() nonlocals_with_same_name = any( child for child in scope.body if isinstance(child, nodes.Nonlocal) and assign_names & set(child.names) ) if nonlocals_with_same_name: scope = node.scope().parent.scope() if not ( isinstance(scope, nodes.FunctionDef) and scope.is_method() and "builtins.staticmethod" not in scope.decoratornames() ): return argument_names = scope.argnames() if not argument_names: return self_cls_name = argument_names[0] target_assign_names = ( target.name for target in node.targets if isinstance(target, nodes.AssignName) ) if self_cls_name in target_assign_names: self.add_message("self-cls-assignment", node=node, args=(self_cls_name,)) def _check_unpacking(self, inferred, node, targets): """Check for unbalanced tuple unpacking and unpacking non sequences. """ if utils.is_inside_abstract_class(node): return if utils.is_comprehension(node): return if inferred is astroid.Uninferable: return if ( isinstance(inferred.parent, nodes.Arguments) and isinstance(node.value, nodes.Name) and node.value.name == inferred.parent.vararg ): # Variable-length argument, we can't determine the length. return if isinstance(inferred, (nodes.Tuple, nodes.List)): # attempt to check unpacking is properly balanced values = inferred.itered() if len(targets) != len(values): # Check if we have starred nodes. if any(isinstance(target, nodes.Starred) for target in targets): return self.add_message( "unbalanced-tuple-unpacking", node=node, args=( _get_unpacking_extra_info(node, inferred), len(targets), len(values), ), ) # attempt to check unpacking may be possible (ie RHS is iterable) elif not utils.is_iterable(inferred): self.add_message( "unpacking-non-sequence", node=node, args=(_get_unpacking_extra_info(node, inferred),), ) 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 """ 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.Uninferable: return None except astroid.NotFoundError: if module.name in self._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: modname = module.name if module else "__dict__" self.add_message( "no-name-in-module", node=node, args=(".".join(module_names), modname) ) return None if isinstance(module, nodes.Module): return module return None def _check_all(self, node: nodes.Module, not_consumed): assigned = next(node.igetattr("__all__")) if assigned is astroid.Uninferable: return if not assigned.pytype() in ["builtins.list", "builtins.tuple"]: line, col = assigned.tolineno, assigned.col_offset self.add_message("invalid-all-format", line=line, col_offset=col, node=node) return for elt in getattr(assigned, "elts", ()): try: elt_name = next(elt.infer()) except astroid.InferenceError: continue if elt_name is astroid.Uninferable: continue if not elt_name.parent: continue if not isinstance(elt_name, nodes.Const) or not isinstance( elt_name.value, str ): 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: astroid.modutils.file_from_modpath(name.split(".")) except ImportError: self.add_message( "undefined-all-variable", args=(elt_name,), node=elt ) except SyntaxError: # don't yield a syntax-error warning, # because it will be later yielded # when the file will be checked pass def _check_globals(self, not_consumed): if self._allow_global_unused_variables: return for name, node_lst in not_consumed.items(): for node in node_lst: self.add_message("unused-variable", args=(name,), node=node) 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) is_type_annotation_import = ( imported_name in self._type_annotation_names or as_name in self._type_annotation_names ) if isinstance(stmt, nodes.Import) or ( isinstance(stmt, nodes.ImportFrom) and not stmt.modname ): if isinstance(stmt, nodes.ImportFrom) and SPECIAL_OBJ.search( imported_name ): # Filter special objects (__doc__, __all__) etc., # because they can be imported for exporting. continue if is_type_annotation_import: # Most likely a typing import if it wasn't used so far. continue if as_name == "_": continue if as_name is None: msg = f"import {imported_name}" else: msg = f"{imported_name} imported as {as_name}" if not _is_type_checking_import(stmt): self.add_message("unused-import", args=msg, node=stmt) elif isinstance(stmt, nodes.ImportFrom) 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 _is_from_future_import(stmt, name): # Check if the name is in fact loaded from a # __future__ import in another module. continue if is_type_annotation_import: # Most likely a typing import if it wasn't used so far. continue if imported_name == "*": self.add_message("unused-wildcard-import", args=name, node=stmt) else: if as_name is None: msg = f"{imported_name} imported from {stmt.modname}" else: msg = f"{imported_name} imported from {stmt.modname} as {as_name}" if not _is_type_checking_import(stmt): self.add_message("unused-import", args=msg, node=stmt) del self._to_consume def _check_metaclasses(self, node): """Update consumption analysis for metaclasses.""" consumed = [] # [(scope_locals, consumed_key)] for child_node in node.get_children(): if isinstance(child_node, nodes.ClassDef): consumed.extend(self._check_classdef_metaclasses(child_node, node)) # Pop the consumed items, in order to avoid having # unused-import and unused-variable false positives for scope_locals, name in consumed: scope_locals.pop(name, None) def _check_classdef_metaclasses(self, klass, parent_node): if not klass._metaclass: # Skip if this class doesn't use explicitly a metaclass, but inherits it from ancestors return [] consumed = [] # [(scope_locals, consumed_key)] metaclass = klass.metaclass() name = None if isinstance(klass._metaclass, nodes.Name): name = klass._metaclass.name elif isinstance(klass._metaclass, nodes.Attribute) and klass._metaclass.expr: attr = klass._metaclass.expr while not isinstance(attr, nodes.Name): attr = attr.expr name = attr.name elif metaclass: name = metaclass.root().name found = None name = METACLASS_NAME_TRANSFORMS.get(name, name) if name: # check enclosing scopes starting from most local for scope_locals, _, _ in self._to_consume[::-1]: found = scope_locals.get(name) if found: consumed.append((scope_locals, name)) break if ( found is None and not metaclass and not ( name in nodes.Module.scope_attrs or utils.is_builtin(name) or name in self.config.additional_builtins or name in parent_node.locals ) ): self.add_message("undefined-variable", node=klass, args=(name,)) return consumed def register(linter): """required method to auto register this checker""" linter.register_checker(VariablesChecker(linter))