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Diffstat (limited to 'venv/Lib/site-packages/pylint/checkers/base.py')
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diff --git a/venv/Lib/site-packages/pylint/checkers/base.py b/venv/Lib/site-packages/pylint/checkers/base.py new file mode 100644 index 0000000..c94676e --- /dev/null +++ b/venv/Lib/site-packages/pylint/checkers/base.py @@ -0,0 +1,2333 @@ +# -*- coding: utf-8 -*- +# Copyright (c) 2006-2016 LOGILAB S.A. (Paris, FRANCE) <contact@logilab.fr> +# Copyright (c) 2010 Daniel Harding <dharding@gmail.com> +# Copyright (c) 2012-2014 Google, Inc. +# Copyright (c) 2013-2018 Claudiu Popa <pcmanticore@gmail.com> +# Copyright (c) 2014 Brett Cannon <brett@python.org> +# Copyright (c) 2014 Arun Persaud <arun@nubati.net> +# Copyright (c) 2015 Nick Bastin <nick.bastin@gmail.com> +# Copyright (c) 2015 Michael Kefeder <oss@multiwave.ch> +# Copyright (c) 2015 Dmitry Pribysh <dmand@yandex.ru> +# Copyright (c) 2015 Stephane Wirtel <stephane@wirtel.be> +# Copyright (c) 2015 Cosmin Poieana <cmin@ropython.org> +# Copyright (c) 2015 Florian Bruhin <me@the-compiler.org> +# Copyright (c) 2015 Radu Ciorba <radu@devrandom.ro> +# Copyright (c) 2015 Ionel Cristian Maries <contact@ionelmc.ro> +# Copyright (c) 2016, 2018 Jakub Wilk <jwilk@jwilk.net> +# Copyright (c) 2016-2017 Łukasz Rogalski <rogalski.91@gmail.com> +# Copyright (c) 2016 Glenn Matthews <glenn@e-dad.net> +# Copyright (c) 2016 Elias Dorneles <eliasdorneles@gmail.com> +# Copyright (c) 2016 Ashley Whetter <ashley@awhetter.co.uk> +# Copyright (c) 2016 Yannack <yannack@users.noreply.github.com> +# Copyright (c) 2016 Alex Jurkiewicz <alex@jurkiewi.cz> +# Copyright (c) 2017 Jacques Kvam <jwkvam@gmail.com> +# Copyright (c) 2017 ttenhoeve-aa <ttenhoeve@appannie.com> +# Copyright (c) 2017 hippo91 <guillaume.peillex@gmail.com> +# Copyright (c) 2018 Nick Drozd <nicholasdrozd@gmail.com> +# Copyright (c) 2018 Steven M. Vascellaro <svascellaro@gmail.com> +# Copyright (c) 2018 Mike Frysinger <vapier@gmail.com> +# Copyright (c) 2018 ssolanki <sushobhitsolanki@gmail.com> +# Copyright (c) 2018 Sushobhit <31987769+sushobhit27@users.noreply.github.com> +# Copyright (c) 2018 Chris Lamb <chris@chris-lamb.co.uk> +# Copyright (c) 2018 glmdgrielson <32415403+glmdgrielson@users.noreply.github.com> +# Copyright (c) 2018 Ville Skyttä <ville.skytta@upcloud.com> + +# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html +# For details: https://github.com/PyCQA/pylint/blob/master/COPYING + +"""basic checker for Python code""" + +import builtins +import collections +import itertools +import re +import sys +from typing import Pattern + +import astroid +import astroid.bases +import astroid.scoped_nodes +from astroid.arguments import CallSite + +import pylint.utils as lint_utils +from pylint import checkers, exceptions, interfaces +from pylint.checkers import utils +from pylint.checkers.utils import is_property_setter_or_deleter +from pylint.reporters.ureports import nodes as reporter_nodes + + +class NamingStyle: + # It may seem counterintuitive that single naming style + # has multiple "accepted" forms of regular expressions, + # but we need to special-case stuff like dunder names + # in method names. + CLASS_NAME_RGX = None # type: Pattern[str] + MOD_NAME_RGX = None # type: Pattern[str] + CONST_NAME_RGX = None # type: Pattern[str] + COMP_VAR_RGX = None # type: Pattern[str] + DEFAULT_NAME_RGX = None # type: Pattern[str] + CLASS_ATTRIBUTE_RGX = None # type: Pattern[str] + + @classmethod + def get_regex(cls, name_type): + return { + "module": cls.MOD_NAME_RGX, + "const": cls.CONST_NAME_RGX, + "class": cls.CLASS_NAME_RGX, + "function": cls.DEFAULT_NAME_RGX, + "method": cls.DEFAULT_NAME_RGX, + "attr": cls.DEFAULT_NAME_RGX, + "argument": cls.DEFAULT_NAME_RGX, + "variable": cls.DEFAULT_NAME_RGX, + "class_attribute": cls.CLASS_ATTRIBUTE_RGX, + "inlinevar": cls.COMP_VAR_RGX, + }[name_type] + + +class SnakeCaseStyle(NamingStyle): + """Regex rules for snake_case naming style.""" + + CLASS_NAME_RGX = re.compile("[a-z_][a-z0-9_]+$") + MOD_NAME_RGX = re.compile("([a-z_][a-z0-9_]*)$") + CONST_NAME_RGX = re.compile("(([a-z_][a-z0-9_]*)|(__.*__))$") + COMP_VAR_RGX = re.compile("[a-z_][a-z0-9_]*$") + DEFAULT_NAME_RGX = re.compile( + "(([a-z_][a-z0-9_]{2,})|(_[a-z0-9_]*)|(__[a-z][a-z0-9_]+__))$" + ) + CLASS_ATTRIBUTE_RGX = re.compile(r"(([a-z_][a-z0-9_]{2,}|(__.*__)))$") + + +class CamelCaseStyle(NamingStyle): + """Regex rules for camelCase naming style.""" + + CLASS_NAME_RGX = re.compile("[a-z_][a-zA-Z0-9]+$") + MOD_NAME_RGX = re.compile("([a-z_][a-zA-Z0-9]*)$") + CONST_NAME_RGX = re.compile("(([a-z_][A-Za-z0-9]*)|(__.*__))$") + COMP_VAR_RGX = re.compile("[a-z_][A-Za-z0-9]*$") + DEFAULT_NAME_RGX = re.compile("(([a-z_][a-zA-Z0-9]{2,})|(__[a-z][a-zA-Z0-9_]+__))$") + CLASS_ATTRIBUTE_RGX = re.compile(r"([a-z_][A-Za-z0-9]{2,}|(__.*__))$") + + +class PascalCaseStyle(NamingStyle): + """Regex rules for PascalCase naming style.""" + + CLASS_NAME_RGX = re.compile("[A-Z_][a-zA-Z0-9]+$") + MOD_NAME_RGX = re.compile("[A-Z_][a-zA-Z0-9]+$") + CONST_NAME_RGX = re.compile("(([A-Z_][A-Za-z0-9]*)|(__.*__))$") + COMP_VAR_RGX = re.compile("[A-Z_][a-zA-Z0-9]+$") + DEFAULT_NAME_RGX = re.compile("[A-Z_][a-zA-Z0-9]{2,}$|(__[a-z][a-zA-Z0-9_]+__)$") + CLASS_ATTRIBUTE_RGX = re.compile("[A-Z_][a-zA-Z0-9]{2,}$") + + +class UpperCaseStyle(NamingStyle): + """Regex rules for UPPER_CASE naming style.""" + + CLASS_NAME_RGX = re.compile("[A-Z_][A-Z0-9_]+$") + MOD_NAME_RGX = re.compile("[A-Z_][A-Z0-9_]+$") + CONST_NAME_RGX = re.compile("(([A-Z_][A-Z0-9_]*)|(__.*__))$") + COMP_VAR_RGX = re.compile("[A-Z_][A-Z0-9_]+$") + DEFAULT_NAME_RGX = re.compile("([A-Z_][A-Z0-9_]{2,})|(__[a-z][a-zA-Z0-9_]+__)$") + CLASS_ATTRIBUTE_RGX = re.compile("[A-Z_][A-Z0-9_]{2,}$") + + +class AnyStyle(NamingStyle): + @classmethod + def get_regex(cls, name_type): + return re.compile(".*") + + +NAMING_STYLES = { + "snake_case": SnakeCaseStyle, + "camelCase": CamelCaseStyle, + "PascalCase": PascalCaseStyle, + "UPPER_CASE": UpperCaseStyle, + "any": AnyStyle, +} + +# do not require a doc string on private/system methods +NO_REQUIRED_DOC_RGX = re.compile("^_") +REVERSED_PROTOCOL_METHOD = "__reversed__" +SEQUENCE_PROTOCOL_METHODS = ("__getitem__", "__len__") +REVERSED_METHODS = (SEQUENCE_PROTOCOL_METHODS, (REVERSED_PROTOCOL_METHOD,)) +TYPECHECK_COMPARISON_OPERATORS = frozenset(("is", "is not", "==", "!=", "in", "not in")) +LITERAL_NODE_TYPES = (astroid.Const, astroid.Dict, astroid.List, astroid.Set) +UNITTEST_CASE = "unittest.case" +BUILTINS = builtins.__name__ +TYPE_QNAME = "%s.type" % BUILTINS +ABC_METACLASSES = {"_py_abc.ABCMeta", "abc.ABCMeta"} # Python 3.7+, + +# Name categories that are always consistent with all naming conventions. +EXEMPT_NAME_CATEGORIES = {"exempt", "ignore"} + +# A mapping from builtin-qname -> symbol, to be used when generating messages +# about dangerous default values as arguments +DEFAULT_ARGUMENT_SYMBOLS = dict( + zip( + [".".join([BUILTINS, x]) for x in ("set", "dict", "list")], + ["set()", "{}", "[]"], + ) +) +REVERSED_COMPS = {"<": ">", "<=": ">=", ">": "<", ">=": "<="} +COMPARISON_OPERATORS = frozenset(("==", "!=", "<", ">", "<=", ">=")) +# List of methods which can be redefined +REDEFINABLE_METHODS = frozenset(("__module__",)) +TYPING_FORWARD_REF_QNAME = "typing.ForwardRef" + + +def _redefines_import(node): + """ Detect that the given node (AssignName) is inside an + exception handler and redefines an import from the tryexcept body. + Returns True if the node redefines an import, False otherwise. + """ + current = node + while current and not isinstance(current.parent, astroid.ExceptHandler): + current = current.parent + if not current or not utils.error_of_type(current.parent, ImportError): + return False + try_block = current.parent.parent + for import_node in try_block.nodes_of_class((astroid.ImportFrom, astroid.Import)): + for name, alias in import_node.names: + if alias: + if alias == node.name: + return True + elif name == node.name: + return True + return False + + +def in_loop(node): + """return True if the node is inside a kind of for loop""" + parent = node.parent + while parent is not None: + if isinstance( + parent, + ( + astroid.For, + astroid.ListComp, + astroid.SetComp, + astroid.DictComp, + astroid.GeneratorExp, + ), + ): + return True + parent = parent.parent + return False + + +def in_nested_list(nested_list, obj): + """return true if the object is an element of <nested_list> or of a nested + list + """ + for elmt in nested_list: + if isinstance(elmt, (list, tuple)): + if in_nested_list(elmt, obj): + return True + elif elmt == obj: + return True + return False + + +def _get_break_loop_node(break_node): + """ + Returns the loop node that holds the break node in arguments. + + Args: + break_node (astroid.Break): the break node of interest. + + Returns: + astroid.For or astroid.While: the loop node holding the break node. + """ + loop_nodes = (astroid.For, astroid.While) + parent = break_node.parent + while not isinstance(parent, loop_nodes) or break_node in getattr( + parent, "orelse", [] + ): + break_node = parent + parent = parent.parent + if parent is None: + break + return parent + + +def _loop_exits_early(loop): + """ + Returns true if a loop may ends up in a break statement. + + Args: + loop (astroid.For, astroid.While): the loop node inspected. + + Returns: + bool: True if the loop may ends up in a break statement, False otherwise. + """ + loop_nodes = (astroid.For, astroid.While) + definition_nodes = (astroid.FunctionDef, astroid.ClassDef) + inner_loop_nodes = [ + _node + for _node in loop.nodes_of_class(loop_nodes, skip_klass=definition_nodes) + if _node != loop + ] + return any( + _node + for _node in loop.nodes_of_class(astroid.Break, skip_klass=definition_nodes) + if _get_break_loop_node(_node) not in inner_loop_nodes + ) + + +def _is_multi_naming_match(match, node_type, confidence): + return ( + match is not None + and match.lastgroup is not None + and match.lastgroup not in EXEMPT_NAME_CATEGORIES + and (node_type != "method" or confidence != interfaces.INFERENCE_FAILURE) + ) + + +BUILTIN_PROPERTY = "builtins.property" + + +def _get_properties(config): + """Returns a tuple of property classes and names. + + Property classes are fully qualified, such as 'abc.abstractproperty' and + property names are the actual names, such as 'abstract_property'. + """ + property_classes = {BUILTIN_PROPERTY} + property_names = set() # Not returning 'property', it has its own check. + if config is not None: + property_classes.update(config.property_classes) + property_names.update( + (prop.rsplit(".", 1)[-1] for prop in config.property_classes) + ) + return property_classes, property_names + + +def _determine_function_name_type(node, config=None): + """Determine the name type whose regex the a function's name should match. + + :param node: A function node. + :type node: astroid.node_classes.NodeNG + :param config: Configuration from which to pull additional property classes. + :type config: :class:`optparse.Values` + + :returns: One of ('function', 'method', 'attr') + :rtype: str + """ + property_classes, property_names = _get_properties(config) + if not node.is_method(): + return "function" + + if is_property_setter_or_deleter(node): + # If the function is decorated using the prop_method.{setter,getter} + # form, treat it like an attribute as well. + return "attr" + + if node.decorators: + decorators = node.decorators.nodes + else: + decorators = [] + for decorator in decorators: + # If the function is a property (decorated with @property + # or @abc.abstractproperty), the name type is 'attr'. + if isinstance(decorator, astroid.Name) or ( + isinstance(decorator, astroid.Attribute) + and decorator.attrname in property_names + ): + inferred = utils.safe_infer(decorator) + if inferred and inferred.qname() in property_classes: + return "attr" + return "method" + + +def _has_abstract_methods(node): + """ + Determine if the given `node` has abstract methods. + + The methods should be made abstract by decorating them + with `abc` decorators. + """ + return len(utils.unimplemented_abstract_methods(node)) > 0 + + +def report_by_type_stats(sect, stats, _): + """make a report of + + * percentage of different types documented + * percentage of different types with a bad name + """ + # percentage of different types documented and/or with a bad name + nice_stats = {} + for node_type in ("module", "class", "method", "function"): + try: + total = stats[node_type] + except KeyError: + raise exceptions.EmptyReportError() + nice_stats[node_type] = {} + if total != 0: + try: + documented = total - stats["undocumented_" + node_type] + percent = (documented * 100.0) / total + nice_stats[node_type]["percent_documented"] = "%.2f" % percent + except KeyError: + nice_stats[node_type]["percent_documented"] = "NC" + try: + percent = (stats["badname_" + node_type] * 100.0) / total + nice_stats[node_type]["percent_badname"] = "%.2f" % percent + except KeyError: + nice_stats[node_type]["percent_badname"] = "NC" + lines = ("type", "number", "old number", "difference", "%documented", "%badname") + for node_type in ("module", "class", "method", "function"): + new = stats[node_type] + lines += ( + node_type, + str(new), + "NC", + "NC", + nice_stats[node_type].get("percent_documented", "0"), + nice_stats[node_type].get("percent_badname", "0"), + ) + sect.append(reporter_nodes.Table(children=lines, cols=6, rheaders=1)) + + +def redefined_by_decorator(node): + """return True if the object is a method redefined via decorator. + + For example: + @property + def x(self): return self._x + @x.setter + def x(self, value): self._x = value + """ + if node.decorators: + for decorator in node.decorators.nodes: + if ( + isinstance(decorator, astroid.Attribute) + and getattr(decorator.expr, "name", None) == node.name + ): + return True + return False + + +class _BasicChecker(checkers.BaseChecker): + __implements__ = interfaces.IAstroidChecker + name = "basic" + + +class BasicErrorChecker(_BasicChecker): + msgs = { + "E0100": ( + "__init__ method is a generator", + "init-is-generator", + "Used when the special class method __init__ is turned into a " + "generator by a yield in its body.", + ), + "E0101": ( + "Explicit return in __init__", + "return-in-init", + "Used when the special class method __init__ has an explicit " + "return value.", + ), + "E0102": ( + "%s already defined line %s", + "function-redefined", + "Used when a function / class / method is redefined.", + ), + "E0103": ( + "%r not properly in loop", + "not-in-loop", + "Used when break or continue keywords are used outside a loop.", + ), + "E0104": ( + "Return outside function", + "return-outside-function", + 'Used when a "return" statement is found outside a function or method.', + ), + "E0105": ( + "Yield outside function", + "yield-outside-function", + 'Used when a "yield" statement is found outside a function or method.', + ), + "E0106": ( + "Return with argument inside generator", + "return-arg-in-generator", + 'Used when a "return" statement with an argument is found ' + "outside in a generator function or method (e.g. with some " + '"yield" statements).', + {"maxversion": (3, 3)}, + ), + "E0107": ( + "Use of the non-existent %s operator", + "nonexistent-operator", + "Used when you attempt to use the C-style pre-increment or " + "pre-decrement operator -- and ++, which doesn't exist in Python.", + ), + "E0108": ( + "Duplicate argument name %s in function definition", + "duplicate-argument-name", + "Duplicate argument names in function definitions are syntax errors.", + ), + "E0110": ( + "Abstract class %r with abstract methods instantiated", + "abstract-class-instantiated", + "Used when an abstract class with `abc.ABCMeta` as metaclass " + "has abstract methods and is instantiated.", + ), + "W0120": ( + "Else clause on loop without a break statement", + "useless-else-on-loop", + "Loops should only have an else clause if they can exit early " + "with a break statement, otherwise the statements under else " + "should be on the same scope as the loop itself.", + ), + "E0112": ( + "More than one starred expression in assignment", + "too-many-star-expressions", + "Emitted when there are more than one starred " + "expressions (`*x`) in an assignment. This is a SyntaxError.", + ), + "E0113": ( + "Starred assignment target must be in a list or tuple", + "invalid-star-assignment-target", + "Emitted when a star expression is used as a starred assignment target.", + ), + "E0114": ( + "Can use starred expression only in assignment target", + "star-needs-assignment-target", + "Emitted when a star expression is not used in an assignment target.", + ), + "E0115": ( + "Name %r is nonlocal and global", + "nonlocal-and-global", + "Emitted when a name is both nonlocal and global.", + ), + "E0116": ( + "'continue' not supported inside 'finally' clause", + "continue-in-finally", + "Emitted when the `continue` keyword is found " + "inside a finally clause, which is a SyntaxError.", + ), + "E0117": ( + "nonlocal name %s found without binding", + "nonlocal-without-binding", + "Emitted when a nonlocal variable does not have an attached " + "name somewhere in the parent scopes", + ), + "E0118": ( + "Name %r is used prior to global declaration", + "used-prior-global-declaration", + "Emitted when a name is used prior a global declaration, " + "which results in an error since Python 3.6.", + {"minversion": (3, 6)}, + ), + } + + @utils.check_messages("function-redefined") + def visit_classdef(self, node): + self._check_redefinition("class", node) + + def _too_many_starred_for_tuple(self, assign_tuple): + starred_count = 0 + for elem in assign_tuple.itered(): + if isinstance(elem, astroid.Tuple): + return self._too_many_starred_for_tuple(elem) + if isinstance(elem, astroid.Starred): + starred_count += 1 + return starred_count > 1 + + @utils.check_messages("too-many-star-expressions", "invalid-star-assignment-target") + def visit_assign(self, node): + # Check *a, *b = ... + assign_target = node.targets[0] + # Check *a = b + if isinstance(node.targets[0], astroid.Starred): + self.add_message("invalid-star-assignment-target", node=node) + + if not isinstance(assign_target, astroid.Tuple): + return + if self._too_many_starred_for_tuple(assign_target): + self.add_message("too-many-star-expressions", node=node) + + @utils.check_messages("star-needs-assignment-target") + def visit_starred(self, node): + """Check that a Starred expression is used in an assignment target.""" + if isinstance(node.parent, astroid.Call): + # f(*args) is converted to Call(args=[Starred]), so ignore + # them for this check. + return + if isinstance( + node.parent, (astroid.List, astroid.Tuple, astroid.Set, astroid.Dict) + ): + # PEP 448 unpacking. + return + + stmt = node.statement() + if not isinstance(stmt, astroid.Assign): + return + + if stmt.value is node or stmt.value.parent_of(node): + self.add_message("star-needs-assignment-target", node=node) + + @utils.check_messages( + "init-is-generator", + "return-in-init", + "function-redefined", + "return-arg-in-generator", + "duplicate-argument-name", + "nonlocal-and-global", + "used-prior-global-declaration", + ) + def visit_functiondef(self, node): + self._check_nonlocal_and_global(node) + self._check_name_used_prior_global(node) + if not redefined_by_decorator( + node + ) and not utils.is_registered_in_singledispatch_function(node): + self._check_redefinition(node.is_method() and "method" or "function", node) + # checks for max returns, branch, return in __init__ + returns = node.nodes_of_class( + astroid.Return, skip_klass=(astroid.FunctionDef, astroid.ClassDef) + ) + if node.is_method() and node.name == "__init__": + if node.is_generator(): + self.add_message("init-is-generator", node=node) + else: + values = [r.value for r in returns] + # Are we returning anything but None from constructors + if any(v for v in values if not utils.is_none(v)): + self.add_message("return-in-init", node=node) + # Check for duplicate names by clustering args with same name for detailed report + arg_clusters = collections.defaultdict(list) + arguments = filter(None, [node.args.args, node.args.kwonlyargs]) + + for arg in itertools.chain.from_iterable(arguments): + arg_clusters[arg.name].append(arg) + + # provide detailed report about each repeated argument + for argument_duplicates in arg_clusters.values(): + if len(argument_duplicates) != 1: + for argument in argument_duplicates: + self.add_message( + "duplicate-argument-name", + line=argument.lineno, + node=argument, + args=(argument.name,), + ) + + visit_asyncfunctiondef = visit_functiondef + + def _check_name_used_prior_global(self, node): + + scope_globals = { + name: child + for child in node.nodes_of_class(astroid.Global) + for name in child.names + if child.scope() is node + } + + if not scope_globals: + return + + for node_name in node.nodes_of_class(astroid.Name): + if node_name.scope() is not node: + continue + + name = node_name.name + corresponding_global = scope_globals.get(name) + if not corresponding_global: + continue + + global_lineno = corresponding_global.fromlineno + if global_lineno and global_lineno > node_name.fromlineno: + self.add_message( + "used-prior-global-declaration", node=node_name, args=(name,) + ) + + def _check_nonlocal_and_global(self, node): + """Check that a name is both nonlocal and global.""" + + def same_scope(current): + return current.scope() is node + + from_iter = itertools.chain.from_iterable + nonlocals = set( + from_iter( + child.names + for child in node.nodes_of_class(astroid.Nonlocal) + if same_scope(child) + ) + ) + + if not nonlocals: + return + + global_vars = set( + from_iter( + child.names + for child in node.nodes_of_class(astroid.Global) + if same_scope(child) + ) + ) + for name in nonlocals.intersection(global_vars): + self.add_message("nonlocal-and-global", args=(name,), node=node) + + @utils.check_messages("return-outside-function") + def visit_return(self, node): + if not isinstance(node.frame(), astroid.FunctionDef): + self.add_message("return-outside-function", node=node) + + @utils.check_messages("yield-outside-function") + def visit_yield(self, node): + self._check_yield_outside_func(node) + + @utils.check_messages("yield-outside-function") + def visit_yieldfrom(self, node): + self._check_yield_outside_func(node) + + @utils.check_messages("not-in-loop", "continue-in-finally") + def visit_continue(self, node): + self._check_in_loop(node, "continue") + + @utils.check_messages("not-in-loop") + def visit_break(self, node): + self._check_in_loop(node, "break") + + @utils.check_messages("useless-else-on-loop") + def visit_for(self, node): + self._check_else_on_loop(node) + + @utils.check_messages("useless-else-on-loop") + def visit_while(self, node): + self._check_else_on_loop(node) + + @utils.check_messages("nonexistent-operator") + def visit_unaryop(self, node): + """check use of the non-existent ++ and -- operator operator""" + if ( + (node.op in "+-") + and isinstance(node.operand, astroid.UnaryOp) + and (node.operand.op == node.op) + ): + self.add_message("nonexistent-operator", node=node, args=node.op * 2) + + def _check_nonlocal_without_binding(self, node, name): + current_scope = node.scope() + while True: + if current_scope.parent is None: + break + + if not isinstance(current_scope, (astroid.ClassDef, astroid.FunctionDef)): + self.add_message("nonlocal-without-binding", args=(name,), node=node) + return + + if name not in current_scope.locals: + current_scope = current_scope.parent.scope() + continue + + # Okay, found it. + return + + if not isinstance(current_scope, astroid.FunctionDef): + self.add_message("nonlocal-without-binding", args=(name,), node=node) + + @utils.check_messages("nonlocal-without-binding") + def visit_nonlocal(self, node): + for name in node.names: + self._check_nonlocal_without_binding(node, name) + + @utils.check_messages("abstract-class-instantiated") + def visit_call(self, node): + """ Check instantiating abstract class with + abc.ABCMeta as metaclass. + """ + try: + for inferred in node.func.infer(): + self._check_inferred_class_is_abstract(inferred, node) + except astroid.InferenceError: + return + + def _check_inferred_class_is_abstract(self, inferred, node): + if not isinstance(inferred, astroid.ClassDef): + return + + klass = utils.node_frame_class(node) + if klass is inferred: + # Don't emit the warning if the class is instantiated + # in its own body or if the call is not an instance + # creation. If the class is instantiated into its own + # body, we're expecting that it knows what it is doing. + return + + # __init__ was called + abstract_methods = _has_abstract_methods(inferred) + + if not abstract_methods: + return + + metaclass = inferred.metaclass() + + if metaclass is None: + # Python 3.4 has `abc.ABC`, which won't be detected + # by ClassNode.metaclass() + for ancestor in inferred.ancestors(): + if ancestor.qname() == "abc.ABC": + self.add_message( + "abstract-class-instantiated", args=(inferred.name,), node=node + ) + break + + return + + if metaclass.qname() in ABC_METACLASSES: + self.add_message( + "abstract-class-instantiated", args=(inferred.name,), node=node + ) + + def _check_yield_outside_func(self, node): + if not isinstance(node.frame(), (astroid.FunctionDef, astroid.Lambda)): + self.add_message("yield-outside-function", node=node) + + def _check_else_on_loop(self, node): + """Check that any loop with an else clause has a break statement.""" + if node.orelse and not _loop_exits_early(node): + self.add_message( + "useless-else-on-loop", + node=node, + # This is not optimal, but the line previous + # to the first statement in the else clause + # will usually be the one that contains the else:. + line=node.orelse[0].lineno - 1, + ) + + def _check_in_loop(self, node, node_name): + """check that a node is inside a for or while loop""" + _node = node.parent + while _node: + if isinstance(_node, (astroid.For, astroid.While)): + if node not in _node.orelse: + return + + if isinstance(_node, (astroid.ClassDef, astroid.FunctionDef)): + break + if ( + isinstance(_node, astroid.TryFinally) + and node in _node.finalbody + and isinstance(node, astroid.Continue) + ): + self.add_message("continue-in-finally", node=node) + + _node = _node.parent + + self.add_message("not-in-loop", node=node, args=node_name) + + def _check_redefinition(self, redeftype, node): + """check for redefinition of a function / method / class name""" + parent_frame = node.parent.frame() + + # Ignore function stubs created for type information + redefinitions = parent_frame.locals[node.name] + defined_self = next( + (local for local in redefinitions if not utils.is_overload_stub(local)), + node, + ) + if defined_self is not node and not astroid.are_exclusive(node, defined_self): + + # Additional checks for methods which are not considered + # redefined, since they are already part of the base API. + if ( + isinstance(parent_frame, astroid.ClassDef) + and node.name in REDEFINABLE_METHODS + ): + return + + if utils.is_overload_stub(node): + return + + # Check if we have forward references for this node. + try: + redefinition_index = redefinitions.index(node) + except ValueError: + pass + else: + for redefinition in redefinitions[:redefinition_index]: + inferred = utils.safe_infer(redefinition) + if ( + inferred + and isinstance(inferred, astroid.Instance) + and inferred.qname() == TYPING_FORWARD_REF_QNAME + ): + return + + dummy_variables_rgx = lint_utils.get_global_option( + self, "dummy-variables-rgx", default=None + ) + if dummy_variables_rgx and dummy_variables_rgx.match(node.name): + return + self.add_message( + "function-redefined", + node=node, + args=(redeftype, defined_self.fromlineno), + ) + + +class BasicChecker(_BasicChecker): + """checks for : + * doc strings + * number of arguments, local variables, branches, returns and statements in + functions, methods + * required module attributes + * dangerous default values as arguments + * redefinition of function / method / class + * uses of the global statement + """ + + __implements__ = interfaces.IAstroidChecker + + name = "basic" + msgs = { + "W0101": ( + "Unreachable code", + "unreachable", + 'Used when there is some code behind a "return" or "raise" ' + "statement, which will never be accessed.", + ), + "W0102": ( + "Dangerous default value %s as argument", + "dangerous-default-value", + "Used when a mutable value as list or dictionary is detected in " + "a default value for an argument.", + ), + "W0104": ( + "Statement seems to have no effect", + "pointless-statement", + "Used when a statement doesn't have (or at least seems to) any effect.", + ), + "W0105": ( + "String statement has no effect", + "pointless-string-statement", + "Used when a string is used as a statement (which of course " + "has no effect). This is a particular case of W0104 with its " + "own message so you can easily disable it if you're using " + "those strings as documentation, instead of comments.", + ), + "W0106": ( + 'Expression "%s" is assigned to nothing', + "expression-not-assigned", + "Used when an expression that is not a function call is assigned " + "to nothing. Probably something else was intended.", + ), + "W0108": ( + "Lambda may not be necessary", + "unnecessary-lambda", + "Used when the body of a lambda expression is a function call " + "on the same argument list as the lambda itself; such lambda " + "expressions are in all but a few cases replaceable with the " + "function being called in the body of the lambda.", + ), + "W0109": ( + "Duplicate key %r in dictionary", + "duplicate-key", + "Used when a dictionary expression binds the same key multiple times.", + ), + "W0122": ( + "Use of exec", + "exec-used", + 'Used when you use the "exec" statement (function for Python ' + "3), to discourage its usage. That doesn't " + "mean you cannot use it !", + ), + "W0123": ( + "Use of eval", + "eval-used", + 'Used when you use the "eval" function, to discourage its ' + "usage. Consider using `ast.literal_eval` for safely evaluating " + "strings containing Python expressions " + "from untrusted sources. ", + ), + "W0150": ( + "%s statement in finally block may swallow exception", + "lost-exception", + "Used when a break or a return statement is found inside the " + "finally clause of a try...finally block: the exceptions raised " + "in the try clause will be silently swallowed instead of being " + "re-raised.", + ), + "W0199": ( + "Assert called on a 2-item-tuple. Did you mean 'assert x,y'?", + "assert-on-tuple", + "A call of assert on a tuple will always evaluate to true if " + "the tuple is not empty, and will always evaluate to false if " + "it is.", + ), + "W0124": ( + 'Following "as" with another context manager looks like a tuple.', + "confusing-with-statement", + "Emitted when a `with` statement component returns multiple values " + "and uses name binding with `as` only for a part of those values, " + "as in with ctx() as a, b. This can be misleading, since it's not " + "clear if the context manager returns a tuple or if the node without " + "a name binding is another context manager.", + ), + "W0125": ( + "Using a conditional statement with a constant value", + "using-constant-test", + "Emitted when a conditional statement (If or ternary if) " + "uses a constant value for its test. This might not be what " + "the user intended to do.", + ), + "W0126": ( + "Using a conditional statement with potentially wrong function or method call due to missing parentheses", + "missing-parentheses-for-call-in-test", + "Emitted when a conditional statement (If or ternary if) " + "seems to wrongly call a function due to missing parentheses", + ), + "W0127": ( + "Assigning the same variable %r to itself", + "self-assigning-variable", + "Emitted when we detect that a variable is assigned to itself", + ), + "W0128": ( + "Redeclared variable %r in assignment", + "redeclared-assigned-name", + "Emitted when we detect that a variable was redeclared in the same assignment.", + ), + "E0111": ( + "The first reversed() argument is not a sequence", + "bad-reversed-sequence", + "Used when the first argument to reversed() builtin " + "isn't a sequence (does not implement __reversed__, " + "nor __getitem__ and __len__", + ), + "E0119": ( + "format function is not called on str", + "misplaced-format-function", + "Emitted when format function is not called on str object. " + 'e.g doing print("value: {}").format(123) instead of ' + 'print("value: {}".format(123)). This might not be what the user ' + "intended to do.", + ), + } + + reports = (("RP0101", "Statistics by type", report_by_type_stats),) + + def __init__(self, linter): + _BasicChecker.__init__(self, linter) + self.stats = None + self._tryfinallys = None + + def open(self): + """initialize visit variables and statistics + """ + self._tryfinallys = [] + self.stats = self.linter.add_stats(module=0, function=0, method=0, class_=0) + + @utils.check_messages("using-constant-test", "missing-parentheses-for-call-in-test") + def visit_if(self, node): + self._check_using_constant_test(node, node.test) + + @utils.check_messages("using-constant-test", "missing-parentheses-for-call-in-test") + def visit_ifexp(self, node): + self._check_using_constant_test(node, node.test) + + @utils.check_messages("using-constant-test", "missing-parentheses-for-call-in-test") + def visit_comprehension(self, node): + if node.ifs: + for if_test in node.ifs: + self._check_using_constant_test(node, if_test) + + def _check_using_constant_test(self, node, test): + const_nodes = ( + astroid.Module, + astroid.scoped_nodes.GeneratorExp, + astroid.Lambda, + astroid.FunctionDef, + astroid.ClassDef, + astroid.bases.Generator, + astroid.UnboundMethod, + astroid.BoundMethod, + astroid.Module, + ) + structs = (astroid.Dict, astroid.Tuple, astroid.Set) + + # These nodes are excepted, since they are not constant + # values, requiring a computation to happen. + except_nodes = ( + astroid.Call, + astroid.BinOp, + astroid.BoolOp, + astroid.UnaryOp, + astroid.Subscript, + ) + inferred = None + emit = isinstance(test, (astroid.Const,) + structs + const_nodes) + if not isinstance(test, except_nodes): + inferred = utils.safe_infer(test) + + if emit: + self.add_message("using-constant-test", node=node) + elif isinstance(inferred, const_nodes): + # If the constant node is a FunctionDef or Lambda then + # it may be a illicit function call due to missing parentheses + call_inferred = None + if isinstance(inferred, astroid.FunctionDef): + call_inferred = inferred.infer_call_result() + elif isinstance(inferred, astroid.Lambda): + call_inferred = inferred.infer_call_result(node) + if call_inferred: + try: + for inf_call in call_inferred: + if inf_call != astroid.Uninferable: + self.add_message( + "missing-parentheses-for-call-in-test", node=node + ) + break + except astroid.InferenceError: + pass + self.add_message("using-constant-test", node=node) + + def visit_module(self, _): + """check module name, docstring and required arguments + """ + self.stats["module"] += 1 + + def visit_classdef(self, node): # pylint: disable=unused-argument + """check module name, docstring and redefinition + increment branch counter + """ + self.stats["class"] += 1 + + @utils.check_messages( + "pointless-statement", "pointless-string-statement", "expression-not-assigned" + ) + def visit_expr(self, node): + """Check for various kind of statements without effect""" + expr = node.value + if isinstance(expr, astroid.Const) and isinstance(expr.value, str): + # treat string statement in a separated message + # Handle PEP-257 attribute docstrings. + # An attribute docstring is defined as being a string right after + # an assignment at the module level, class level or __init__ level. + scope = expr.scope() + if isinstance( + scope, (astroid.ClassDef, astroid.Module, astroid.FunctionDef) + ): + if isinstance(scope, astroid.FunctionDef) and scope.name != "__init__": + pass + else: + sibling = expr.previous_sibling() + if ( + sibling is not None + and sibling.scope() is scope + and isinstance(sibling, (astroid.Assign, astroid.AnnAssign)) + ): + return + self.add_message("pointless-string-statement", node=node) + return + + # Ignore if this is : + # * a direct function call + # * the unique child of a try/except body + # * a yield statement + # * an ellipsis (which can be used on Python 3 instead of pass) + # warn W0106 if we have any underlying function call (we can't predict + # side effects), else pointless-statement + if ( + isinstance( + expr, (astroid.Yield, astroid.Await, astroid.Ellipsis, astroid.Call) + ) + or ( + isinstance(node.parent, astroid.TryExcept) + and node.parent.body == [node] + ) + or (isinstance(expr, astroid.Const) and expr.value is Ellipsis) + ): + return + if any(expr.nodes_of_class(astroid.Call)): + self.add_message( + "expression-not-assigned", node=node, args=expr.as_string() + ) + else: + self.add_message("pointless-statement", node=node) + + @staticmethod + def _filter_vararg(node, call_args): + # Return the arguments for the given call which are + # not passed as vararg. + for arg in call_args: + if isinstance(arg, astroid.Starred): + if ( + isinstance(arg.value, astroid.Name) + and arg.value.name != node.args.vararg + ): + yield arg + else: + yield arg + + @staticmethod + def _has_variadic_argument(args, variadic_name): + if not args: + return True + for arg in args: + if isinstance(arg.value, astroid.Name): + if arg.value.name != variadic_name: + return True + else: + return True + return False + + @utils.check_messages("unnecessary-lambda") + def visit_lambda(self, node): + """check whether or not the lambda is suspicious + """ + # if the body of the lambda is a call expression with the same + # argument list as the lambda itself, then the lambda is + # possibly unnecessary and at least suspicious. + if node.args.defaults: + # If the arguments of the lambda include defaults, then a + # judgment cannot be made because there is no way to check + # that the defaults defined by the lambda are the same as + # the defaults defined by the function called in the body + # of the lambda. + return + call = node.body + if not isinstance(call, astroid.Call): + # The body of the lambda must be a function call expression + # for the lambda to be unnecessary. + return + if isinstance(node.body.func, astroid.Attribute) and isinstance( + node.body.func.expr, astroid.Call + ): + # Chained call, the intermediate call might + # return something else (but we don't check that, yet). + return + + call_site = CallSite.from_call(call) + ordinary_args = list(node.args.args) + new_call_args = list(self._filter_vararg(node, call.args)) + if node.args.kwarg: + if self._has_variadic_argument(call.kwargs, node.args.kwarg): + return + + if node.args.vararg: + if self._has_variadic_argument(call.starargs, node.args.vararg): + return + elif call.starargs: + return + + if call.keywords: + # Look for additional keyword arguments that are not part + # of the lambda's signature + lambda_kwargs = {keyword.name for keyword in node.args.defaults} + if len(lambda_kwargs) != len(call_site.keyword_arguments): + # Different lengths, so probably not identical + return + if set(call_site.keyword_arguments).difference(lambda_kwargs): + return + + # The "ordinary" arguments must be in a correspondence such that: + # ordinary_args[i].name == call.args[i].name. + if len(ordinary_args) != len(new_call_args): + return + for arg, passed_arg in zip(ordinary_args, new_call_args): + if not isinstance(passed_arg, astroid.Name): + return + if arg.name != passed_arg.name: + return + + self.add_message("unnecessary-lambda", line=node.fromlineno, node=node) + + @utils.check_messages("dangerous-default-value") + def visit_functiondef(self, node): + """check function name, docstring, arguments, redefinition, + variable names, max locals + """ + self.stats["method" if node.is_method() else "function"] += 1 + self._check_dangerous_default(node) + + visit_asyncfunctiondef = visit_functiondef + + def _check_dangerous_default(self, node): + # check for dangerous default values as arguments + is_iterable = lambda n: isinstance(n, (astroid.List, astroid.Set, astroid.Dict)) + for default in node.args.defaults: + try: + value = next(default.infer()) + except astroid.InferenceError: + continue + + if ( + isinstance(value, astroid.Instance) + and value.qname() in DEFAULT_ARGUMENT_SYMBOLS + ): + + if value is default: + msg = DEFAULT_ARGUMENT_SYMBOLS[value.qname()] + elif isinstance(value, astroid.Instance) or is_iterable(value): + # We are here in the following situation(s): + # * a dict/set/list/tuple call which wasn't inferred + # to a syntax node ({}, () etc.). This can happen + # when the arguments are invalid or unknown to + # the inference. + # * a variable from somewhere else, which turns out to be a list + # or a dict. + if is_iterable(default): + msg = value.pytype() + elif isinstance(default, astroid.Call): + msg = "%s() (%s)" % (value.name, value.qname()) + else: + msg = "%s (%s)" % (default.as_string(), value.qname()) + else: + # this argument is a name + msg = "%s (%s)" % ( + default.as_string(), + DEFAULT_ARGUMENT_SYMBOLS[value.qname()], + ) + self.add_message("dangerous-default-value", node=node, args=(msg,)) + + @utils.check_messages("unreachable", "lost-exception") + def visit_return(self, node): + """1 - check is the node has a right sibling (if so, that's some + unreachable code) + 2 - check is the node is inside the finally clause of a try...finally + block + """ + self._check_unreachable(node) + # Is it inside final body of a try...finally bloc ? + self._check_not_in_finally(node, "return", (astroid.FunctionDef,)) + + @utils.check_messages("unreachable") + def visit_continue(self, node): + """check is the node has a right sibling (if so, that's some unreachable + code) + """ + self._check_unreachable(node) + + @utils.check_messages("unreachable", "lost-exception") + def visit_break(self, node): + """1 - check is the node has a right sibling (if so, that's some + unreachable code) + 2 - check is the node is inside the finally clause of a try...finally + block + """ + # 1 - Is it right sibling ? + self._check_unreachable(node) + # 2 - Is it inside final body of a try...finally bloc ? + self._check_not_in_finally(node, "break", (astroid.For, astroid.While)) + + @utils.check_messages("unreachable") + def visit_raise(self, node): + """check if the node has a right sibling (if so, that's some unreachable + code) + """ + self._check_unreachable(node) + + @utils.check_messages("exec-used") + def visit_exec(self, node): + """just print a warning on exec statements""" + self.add_message("exec-used", node=node) + + def _check_misplaced_format_function(self, call_node): + if not isinstance(call_node.func, astroid.Attribute): + return + if call_node.func.attrname != "format": + return + + expr = utils.safe_infer(call_node.func.expr) + if expr is astroid.Uninferable: + return + if not expr: + # we are doubtful on inferred type of node, so here just check if format + # was called on print() + call_expr = call_node.func.expr + if not isinstance(call_expr, astroid.Call): + return + if ( + isinstance(call_expr.func, astroid.Name) + and call_expr.func.name == "print" + ): + self.add_message("misplaced-format-function", node=call_node) + + @utils.check_messages( + "eval-used", "exec-used", "bad-reversed-sequence", "misplaced-format-function" + ) + def visit_call(self, node): + """visit a Call node -> check if this is not a blacklisted builtin + call and check for * or ** use + """ + self._check_misplaced_format_function(node) + if isinstance(node.func, astroid.Name): + name = node.func.name + # ignore the name if it's not a builtin (i.e. not defined in the + # locals nor globals scope) + if not (name in node.frame() or name in node.root()): + if name == "exec": + self.add_message("exec-used", node=node) + elif name == "reversed": + self._check_reversed(node) + elif name == "eval": + self.add_message("eval-used", node=node) + + @utils.check_messages("assert-on-tuple") + def visit_assert(self, node): + """check the use of an assert statement on a tuple.""" + if ( + node.fail is None + and isinstance(node.test, astroid.Tuple) + and len(node.test.elts) == 2 + ): + self.add_message("assert-on-tuple", node=node) + + @utils.check_messages("duplicate-key") + def visit_dict(self, node): + """check duplicate key in dictionary""" + keys = set() + for k, _ in node.items: + if isinstance(k, astroid.Const): + key = k.value + if key in keys: + self.add_message("duplicate-key", node=node, args=key) + keys.add(key) + + def visit_tryfinally(self, node): + """update try...finally flag""" + self._tryfinallys.append(node) + + def leave_tryfinally(self, node): # pylint: disable=unused-argument + """update try...finally flag""" + self._tryfinallys.pop() + + def _check_unreachable(self, node): + """check unreachable code""" + unreach_stmt = node.next_sibling() + if unreach_stmt is not None: + self.add_message("unreachable", node=unreach_stmt) + + def _check_not_in_finally(self, node, node_name, breaker_classes=()): + """check that a node is not inside a finally clause of a + try...finally statement. + If we found before a try...finally bloc a parent which its type is + in breaker_classes, we skip the whole check.""" + # if self._tryfinallys is empty, we're not an in try...finally block + if not self._tryfinallys: + return + # the node could be a grand-grand...-children of the try...finally + _parent = node.parent + _node = node + while _parent and not isinstance(_parent, breaker_classes): + if hasattr(_parent, "finalbody") and _node in _parent.finalbody: + self.add_message("lost-exception", node=node, args=node_name) + return + _node = _parent + _parent = _node.parent + + def _check_reversed(self, node): + """ check that the argument to `reversed` is a sequence """ + try: + argument = utils.safe_infer(utils.get_argument_from_call(node, position=0)) + except utils.NoSuchArgumentError: + pass + else: + if argument is astroid.Uninferable: + return + if argument is None: + # Nothing was inferred. + # Try to see if we have iter(). + if isinstance(node.args[0], astroid.Call): + try: + func = next(node.args[0].func.infer()) + except astroid.InferenceError: + return + if getattr( + func, "name", None + ) == "iter" and utils.is_builtin_object(func): + self.add_message("bad-reversed-sequence", node=node) + return + + if isinstance(argument, (astroid.List, astroid.Tuple)): + return + + if isinstance(argument, astroid.Instance): + if argument._proxied.name == "dict" and utils.is_builtin_object( + argument._proxied + ): + self.add_message("bad-reversed-sequence", node=node) + return + if any( + ancestor.name == "dict" and utils.is_builtin_object(ancestor) + for ancestor in argument._proxied.ancestors() + ): + # Mappings aren't accepted by reversed(), unless + # they provide explicitly a __reversed__ method. + try: + argument.locals[REVERSED_PROTOCOL_METHOD] + except KeyError: + self.add_message("bad-reversed-sequence", node=node) + return + + if hasattr(argument, "getattr"): + # everything else is not a proper sequence for reversed() + for methods in REVERSED_METHODS: + for meth in methods: + try: + argument.getattr(meth) + except astroid.NotFoundError: + break + else: + break + else: + self.add_message("bad-reversed-sequence", node=node) + else: + self.add_message("bad-reversed-sequence", node=node) + + @utils.check_messages("confusing-with-statement") + def visit_with(self, node): + # a "with" statement with multiple managers coresponds + # to one AST "With" node with multiple items + pairs = node.items + if pairs: + for prev_pair, pair in zip(pairs, pairs[1:]): + if isinstance(prev_pair[1], astroid.AssignName) and ( + pair[1] is None and not isinstance(pair[0], astroid.Call) + ): + # Don't emit a message if the second is a function call + # there's no way that can be mistaken for a name assignment. + # If the line number doesn't match + # we assume it's a nested "with". + self.add_message("confusing-with-statement", node=node) + + def _check_self_assigning_variable(self, node): + # Detect assigning to the same variable. + + scope = node.scope() + scope_locals = scope.locals + + rhs_names = [] + targets = node.targets + if isinstance(targets[0], astroid.Tuple): + if len(targets) != 1: + # A complex assignment, so bail out early. + return + targets = targets[0].elts + + if isinstance(node.value, astroid.Name): + if len(targets) != 1: + return + rhs_names = [node.value] + elif isinstance(node.value, astroid.Tuple): + rhs_count = len(node.value.elts) + if len(targets) != rhs_count or rhs_count == 1: + return + rhs_names = node.value.elts + + for target, lhs_name in zip(targets, rhs_names): + if not isinstance(lhs_name, astroid.Name): + continue + if not isinstance(target, astroid.AssignName): + continue + if isinstance(scope, astroid.ClassDef) and target.name in scope_locals: + # Check that the scope is different than a class level, which is usually + # a pattern to expose module level attributes as class level ones. + continue + if target.name == lhs_name.name: + self.add_message( + "self-assigning-variable", args=(target.name,), node=target + ) + + def _check_redeclared_assign_name(self, targets): + for target in targets: + if not isinstance(target, astroid.Tuple): + continue + + found_names = [] + for element in target.elts: + if isinstance(element, astroid.Tuple): + self._check_redeclared_assign_name([element]) + elif isinstance(element, astroid.AssignName) and element.name != "_": + found_names.append(element.name) + + names = collections.Counter(found_names) + for name, count in names.most_common(): + if count > 1: + self.add_message( + "redeclared-assigned-name", args=(name,), node=target + ) + + @utils.check_messages("self-assigning-variable", "redeclared-assigned-name") + def visit_assign(self, node): + self._check_self_assigning_variable(node) + self._check_redeclared_assign_name(node.targets) + + @utils.check_messages("redeclared-assigned-name") + def visit_for(self, node): + self._check_redeclared_assign_name([node.target]) + + +KNOWN_NAME_TYPES = { + "module", + "const", + "class", + "function", + "method", + "attr", + "argument", + "variable", + "class_attribute", + "inlinevar", +} + + +HUMAN_READABLE_TYPES = { + "module": "module", + "const": "constant", + "class": "class", + "function": "function", + "method": "method", + "attr": "attribute", + "argument": "argument", + "variable": "variable", + "class_attribute": "class attribute", + "inlinevar": "inline iteration", +} + +DEFAULT_NAMING_STYLES = { + "module": "snake_case", + "const": "UPPER_CASE", + "class": "PascalCase", + "function": "snake_case", + "method": "snake_case", + "attr": "snake_case", + "argument": "snake_case", + "variable": "snake_case", + "class_attribute": "any", + "inlinevar": "any", +} + + +def _create_naming_options(): + name_options = [] + for name_type in sorted(KNOWN_NAME_TYPES): + human_readable_name = HUMAN_READABLE_TYPES[name_type] + default_style = DEFAULT_NAMING_STYLES[name_type] + name_type = name_type.replace("_", "-") + name_options.append( + ( + "%s-naming-style" % (name_type,), + { + "default": default_style, + "type": "choice", + "choices": list(NAMING_STYLES.keys()), + "metavar": "<style>", + "help": "Naming style matching correct %s names." + % (human_readable_name,), + }, + ) + ) + name_options.append( + ( + "%s-rgx" % (name_type,), + { + "default": None, + "type": "regexp", + "metavar": "<regexp>", + "help": "Regular expression matching correct %s names. Overrides %s-naming-style." + % (human_readable_name, name_type), + }, + ) + ) + return tuple(name_options) + + +class NameChecker(_BasicChecker): + + msgs = { + "C0102": ( + 'Black listed name "%s"', + "blacklisted-name", + "Used when the name is listed in the black list (unauthorized names).", + ), + "C0103": ( + '%s name "%s" doesn\'t conform to %s', + "invalid-name", + "Used when the name doesn't conform to naming rules " + "associated to its type (constant, variable, class...).", + ), + "W0111": ( + "Name %s will become a keyword in Python %s", + "assign-to-new-keyword", + "Used when assignment will become invalid in future " + "Python release due to introducing new keyword.", + ), + } + + options = ( + ( + "good-names", + { + "default": ("i", "j", "k", "ex", "Run", "_"), + "type": "csv", + "metavar": "<names>", + "help": "Good variable names which should always be accepted," + " separated by a comma.", + }, + ), + ( + "bad-names", + { + "default": ("foo", "bar", "baz", "toto", "tutu", "tata"), + "type": "csv", + "metavar": "<names>", + "help": "Bad variable names which should always be refused, " + "separated by a comma.", + }, + ), + ( + "name-group", + { + "default": (), + "type": "csv", + "metavar": "<name1:name2>", + "help": ( + "Colon-delimited sets of names that determine each" + " other's naming style when the name regexes" + " allow several styles." + ), + }, + ), + ( + "include-naming-hint", + { + "default": False, + "type": "yn", + "metavar": "<y_or_n>", + "help": "Include a hint for the correct naming format with invalid-name.", + }, + ), + ( + "property-classes", + { + "default": ("abc.abstractproperty",), + "type": "csv", + "metavar": "<decorator names>", + "help": "List of decorators that produce properties, such as " + "abc.abstractproperty. Add to this list to register " + "other decorators that produce valid properties. " + "These decorators are taken in consideration only for invalid-name.", + }, + ), + ) + _create_naming_options() + + KEYWORD_ONSET = {(3, 7): {"async", "await"}} + + def __init__(self, linter): + _BasicChecker.__init__(self, linter) + self._name_category = {} + self._name_group = {} + self._bad_names = {} + self._name_regexps = {} + self._name_hints = {} + + def open(self): + self.stats = self.linter.add_stats( + badname_module=0, + badname_class=0, + badname_function=0, + badname_method=0, + badname_attr=0, + badname_const=0, + badname_variable=0, + badname_inlinevar=0, + badname_argument=0, + badname_class_attribute=0, + ) + for group in self.config.name_group: + for name_type in group.split(":"): + self._name_group[name_type] = "group_%s" % (group,) + + regexps, hints = self._create_naming_rules() + self._name_regexps = regexps + self._name_hints = hints + + def _create_naming_rules(self): + regexps = {} + hints = {} + + for name_type in KNOWN_NAME_TYPES: + naming_style_option_name = "%s_naming_style" % (name_type,) + naming_style_name = getattr(self.config, naming_style_option_name) + + regexps[name_type] = NAMING_STYLES[naming_style_name].get_regex(name_type) + + custom_regex_setting_name = "%s_rgx" % (name_type,) + custom_regex = getattr(self.config, custom_regex_setting_name, None) + if custom_regex is not None: + regexps[name_type] = custom_regex + + if custom_regex is not None: + hints[name_type] = "%r pattern" % custom_regex.pattern + else: + hints[name_type] = "%s naming style" % naming_style_name + + return regexps, hints + + @utils.check_messages("blacklisted-name", "invalid-name") + def visit_module(self, node): + self._check_name("module", node.name.split(".")[-1], node) + self._bad_names = {} + + def leave_module(self, node): # pylint: disable=unused-argument + for all_groups in self._bad_names.values(): + if len(all_groups) < 2: + continue + groups = collections.defaultdict(list) + min_warnings = sys.maxsize + for group in all_groups.values(): + groups[len(group)].append(group) + min_warnings = min(len(group), min_warnings) + if len(groups[min_warnings]) > 1: + by_line = sorted( + groups[min_warnings], + key=lambda group: min(warning[0].lineno for warning in group), + ) + warnings = itertools.chain(*by_line[1:]) + else: + warnings = groups[min_warnings][0] + for args in warnings: + self._raise_name_warning(*args) + + @utils.check_messages("blacklisted-name", "invalid-name", "assign-to-new-keyword") + def visit_classdef(self, node): + self._check_assign_to_new_keyword_violation(node.name, node) + self._check_name("class", node.name, node) + for attr, anodes in node.instance_attrs.items(): + if not any(node.instance_attr_ancestors(attr)): + self._check_name("attr", attr, anodes[0]) + + @utils.check_messages("blacklisted-name", "invalid-name", "assign-to-new-keyword") + def visit_functiondef(self, node): + # Do not emit any warnings if the method is just an implementation + # of a base class method. + self._check_assign_to_new_keyword_violation(node.name, node) + confidence = interfaces.HIGH + if node.is_method(): + if utils.overrides_a_method(node.parent.frame(), node.name): + return + confidence = ( + interfaces.INFERENCE + if utils.has_known_bases(node.parent.frame()) + else interfaces.INFERENCE_FAILURE + ) + + self._check_name( + _determine_function_name_type(node, config=self.config), + node.name, + node, + confidence, + ) + # Check argument names + args = node.args.args + if args is not None: + self._recursive_check_names(args, node) + + visit_asyncfunctiondef = visit_functiondef + + @utils.check_messages("blacklisted-name", "invalid-name") + def visit_global(self, node): + for name in node.names: + self._check_name("const", name, node) + + @utils.check_messages("blacklisted-name", "invalid-name", "assign-to-new-keyword") + def visit_assignname(self, node): + """check module level assigned names""" + self._check_assign_to_new_keyword_violation(node.name, node) + frame = node.frame() + assign_type = node.assign_type() + if isinstance(assign_type, astroid.Comprehension): + self._check_name("inlinevar", node.name, node) + elif isinstance(frame, astroid.Module): + if isinstance(assign_type, astroid.Assign) and not in_loop(assign_type): + if isinstance(utils.safe_infer(assign_type.value), astroid.ClassDef): + self._check_name("class", node.name, node) + else: + if not _redefines_import(node): + # Don't emit if the name redefines an import + # in an ImportError except handler. + self._check_name("const", node.name, node) + elif isinstance(assign_type, astroid.ExceptHandler): + self._check_name("variable", node.name, node) + elif isinstance(frame, astroid.FunctionDef): + # global introduced variable aren't in the function locals + if node.name in frame and node.name not in frame.argnames(): + if not _redefines_import(node): + self._check_name("variable", node.name, node) + elif isinstance(frame, astroid.ClassDef): + if not list(frame.local_attr_ancestors(node.name)): + self._check_name("class_attribute", node.name, node) + + def _recursive_check_names(self, args, node): + """check names in a possibly recursive list <arg>""" + for arg in args: + if isinstance(arg, astroid.AssignName): + self._check_name("argument", arg.name, node) + else: + self._recursive_check_names(arg.elts, node) + + def _find_name_group(self, node_type): + return self._name_group.get(node_type, node_type) + + def _raise_name_warning(self, node, node_type, name, confidence): + type_label = HUMAN_READABLE_TYPES[node_type] + hint = self._name_hints[node_type] + if self.config.include_naming_hint: + hint += " (%r pattern)" % self._name_regexps[node_type].pattern + args = (type_label.capitalize(), name, hint) + + self.add_message("invalid-name", node=node, args=args, confidence=confidence) + self.stats["badname_" + node_type] += 1 + + def _check_name(self, node_type, name, node, confidence=interfaces.HIGH): + """check for a name using the type's regexp""" + + def _should_exempt_from_invalid_name(node): + if node_type == "variable": + inferred = utils.safe_infer(node) + if isinstance(inferred, astroid.ClassDef): + return True + return False + + if utils.is_inside_except(node): + clobbering, _ = utils.clobber_in_except(node) + if clobbering: + return + if name in self.config.good_names: + return + if name in self.config.bad_names: + self.stats["badname_" + node_type] += 1 + self.add_message("blacklisted-name", node=node, args=name) + return + regexp = self._name_regexps[node_type] + match = regexp.match(name) + + if _is_multi_naming_match(match, node_type, confidence): + name_group = self._find_name_group(node_type) + bad_name_group = self._bad_names.setdefault(name_group, {}) + warnings = bad_name_group.setdefault(match.lastgroup, []) + warnings.append((node, node_type, name, confidence)) + + if match is None and not _should_exempt_from_invalid_name(node): + self._raise_name_warning(node, node_type, name, confidence) + + def _check_assign_to_new_keyword_violation(self, name, node): + keyword_first_version = self._name_became_keyword_in_version( + name, self.KEYWORD_ONSET + ) + if keyword_first_version is not None: + self.add_message( + "assign-to-new-keyword", + node=node, + args=(name, keyword_first_version), + confidence=interfaces.HIGH, + ) + + @staticmethod + def _name_became_keyword_in_version(name, rules): + for version, keywords in rules.items(): + if name in keywords and sys.version_info < version: + return ".".join(map(str, version)) + return None + + +class DocStringChecker(_BasicChecker): + msgs = { + "C0112": ( + "Empty %s docstring", + "empty-docstring", + "Used when a module, function, class or method has an empty " + "docstring (it would be too easy ;).", + {"old_names": [("W0132", "old-empty-docstring")]}, + ), + "C0114": ( + "Missing module docstring", + "missing-module-docstring", + "Used when a module has no docstring." + "Empty modules do not require a docstring.", + {"old_names": [("C0111", "missing-docstring")]}, + ), + "C0115": ( + "Missing class docstring", + "missing-class-docstring", + "Used when a class has no docstring." + "Even an empty class must have a docstring.", + {"old_names": [("C0111", "missing-docstring")]}, + ), + "C0116": ( + "Missing function or method docstring", + "missing-function-docstring", + "Used when a function or method has no docstring." + "Some special methods like __init__ do not require a " + "docstring.", + {"old_names": [("C0111", "missing-docstring")]}, + ), + } + options = ( + ( + "no-docstring-rgx", + { + "default": NO_REQUIRED_DOC_RGX, + "type": "regexp", + "metavar": "<regexp>", + "help": "Regular expression which should only match " + "function or class names that do not require a " + "docstring.", + }, + ), + ( + "docstring-min-length", + { + "default": -1, + "type": "int", + "metavar": "<int>", + "help": ( + "Minimum line length for functions/classes that" + " require docstrings, shorter ones are exempt." + ), + }, + ), + ) + + def open(self): + self.stats = self.linter.add_stats( + undocumented_module=0, + undocumented_function=0, + undocumented_method=0, + undocumented_class=0, + ) + + @utils.check_messages("missing-docstring", "empty-docstring") + def visit_module(self, node): + self._check_docstring("module", node) + + @utils.check_messages("missing-docstring", "empty-docstring") + def visit_classdef(self, node): + if self.config.no_docstring_rgx.match(node.name) is None: + self._check_docstring("class", node) + + @utils.check_messages("missing-docstring", "empty-docstring") + def visit_functiondef(self, node): + if self.config.no_docstring_rgx.match(node.name) is None: + ftype = "method" if node.is_method() else "function" + if is_property_setter_or_deleter(node): + return + + if isinstance(node.parent.frame(), astroid.ClassDef): + overridden = False + confidence = ( + interfaces.INFERENCE + if utils.has_known_bases(node.parent.frame()) + else interfaces.INFERENCE_FAILURE + ) + # check if node is from a method overridden by its ancestor + for ancestor in node.parent.frame().ancestors(): + if node.name in ancestor and isinstance( + ancestor[node.name], astroid.FunctionDef + ): + overridden = True + break + self._check_docstring( + ftype, node, report_missing=not overridden, confidence=confidence + ) + elif isinstance(node.parent.frame(), astroid.Module): + self._check_docstring(ftype, node) + else: + return + + visit_asyncfunctiondef = visit_functiondef + + def _check_docstring( + self, node_type, node, report_missing=True, confidence=interfaces.HIGH + ): + """check the node has a non empty docstring""" + docstring = node.doc + if docstring is None: + if not report_missing: + return + lines = utils.get_node_last_lineno(node) - node.lineno + + if node_type == "module" and not lines: + # If the module has no body, there's no reason + # to require a docstring. + return + max_lines = self.config.docstring_min_length + + if node_type != "module" and max_lines > -1 and lines < max_lines: + return + self.stats["undocumented_" + node_type] += 1 + if ( + node.body + and isinstance(node.body[0], astroid.Expr) + and isinstance(node.body[0].value, astroid.Call) + ): + # Most likely a string with a format call. Let's see. + func = utils.safe_infer(node.body[0].value.func) + if isinstance(func, astroid.BoundMethod) and isinstance( + func.bound, astroid.Instance + ): + # Strings. + if func.bound.name == "str": + return + if func.bound.name in ("str", "unicode", "bytes"): + return + if node_type == "module": + message = "missing-module-docstring" + elif node_type == "class": + message = "missing-class-docstring" + else: + message = "missing-function-docstring" + self.add_message(message, node=node, confidence=confidence) + elif not docstring.strip(): + self.stats["undocumented_" + node_type] += 1 + self.add_message( + "empty-docstring", node=node, args=(node_type,), confidence=confidence + ) + + +class PassChecker(_BasicChecker): + """check if the pass statement is really necessary""" + + msgs = { + "W0107": ( + "Unnecessary pass statement", + "unnecessary-pass", + 'Used when a "pass" statement that can be avoided is encountered.', + ) + } + + @utils.check_messages("unnecessary-pass") + def visit_pass(self, node): + if len(node.parent.child_sequence(node)) > 1 or ( + isinstance(node.parent, (astroid.ClassDef, astroid.FunctionDef)) + and (node.parent.doc is not None) + ): + self.add_message("unnecessary-pass", node=node) + + +def _is_one_arg_pos_call(call): + """Is this a call with exactly 1 argument, + where that argument is positional? + """ + return isinstance(call, astroid.Call) and len(call.args) == 1 and not call.keywords + + +class ComparisonChecker(_BasicChecker): + """Checks for comparisons + + - singleton comparison: 'expr == True', 'expr == False' and 'expr == None' + - yoda condition: 'const "comp" right' where comp can be '==', '!=', '<', + '<=', '>' or '>=', and right can be a variable, an attribute, a method or + a function + """ + + msgs = { + "C0121": ( + "Comparison to %s should be %s", + "singleton-comparison", + "Used when an expression is compared to singleton " + "values like True, False or None.", + ), + "C0122": ( + "Comparison should be %s", + "misplaced-comparison-constant", + "Used when the constant is placed on the left side " + "of a comparison. It is usually clearer in intent to " + "place it in the right hand side of the comparison.", + ), + "C0123": ( + "Using type() instead of isinstance() for a typecheck.", + "unidiomatic-typecheck", + "The idiomatic way to perform an explicit typecheck in " + "Python is to use isinstance(x, Y) rather than " + "type(x) == Y, type(x) is Y. Though there are unusual " + "situations where these give different results.", + {"old_names": [("W0154", "old-unidiomatic-typecheck")]}, + ), + "R0123": ( + "Comparison to literal", + "literal-comparison", + "Used when comparing an object to a literal, which is usually " + "what you do not want to do, since you can compare to a different " + "literal than what was expected altogether.", + ), + "R0124": ( + "Redundant comparison - %s", + "comparison-with-itself", + "Used when something is compared against itself.", + ), + "W0143": ( + "Comparing against a callable, did you omit the parenthesis?", + "comparison-with-callable", + "This message is emitted when pylint detects that a comparison with a " + "callable was made, which might suggest that some parenthesis were omitted, " + "resulting in potential unwanted behaviour.", + ), + } + + def _check_singleton_comparison(self, singleton, root_node, negative_check=False): + if singleton.value is True: + if not negative_check: + suggestion = "just 'expr'" + else: + suggestion = "just 'not expr'" + self.add_message( + "singleton-comparison", node=root_node, args=(True, suggestion) + ) + elif singleton.value is False: + if not negative_check: + suggestion = "'not expr'" + else: + suggestion = "'expr'" + self.add_message( + "singleton-comparison", node=root_node, args=(False, suggestion) + ) + elif singleton.value is None: + if not negative_check: + suggestion = "'expr is None'" + else: + suggestion = "'expr is not None'" + self.add_message( + "singleton-comparison", node=root_node, args=(None, suggestion) + ) + + def _check_literal_comparison(self, literal, node): + """Check if we compare to a literal, which is usually what we do not want to do.""" + nodes = (astroid.List, astroid.Tuple, astroid.Dict, astroid.Set) + is_other_literal = isinstance(literal, nodes) + is_const = False + if isinstance(literal, astroid.Const): + if isinstance(literal.value, bool) or literal.value is None: + # Not interested in this values. + return + is_const = isinstance(literal.value, (bytes, str, int, float)) + + if is_const or is_other_literal: + self.add_message("literal-comparison", node=node) + + def _check_misplaced_constant(self, node, left, right, operator): + if isinstance(right, astroid.Const): + return + operator = REVERSED_COMPS.get(operator, operator) + suggestion = "%s %s %r" % (right.as_string(), operator, left.value) + self.add_message("misplaced-comparison-constant", node=node, args=(suggestion,)) + + def _check_logical_tautology(self, node): + """Check if identifier is compared against itself. + :param node: Compare node + :type node: astroid.node_classes.Compare + :Example: + val = 786 + if val == val: # [comparison-with-itself] + pass + """ + left_operand = node.left + right_operand = node.ops[0][1] + operator = node.ops[0][0] + if isinstance(left_operand, astroid.Const) and isinstance( + right_operand, astroid.Const + ): + left_operand = left_operand.value + right_operand = right_operand.value + elif isinstance(left_operand, astroid.Name) and isinstance( + right_operand, astroid.Name + ): + left_operand = left_operand.name + right_operand = right_operand.name + + if left_operand == right_operand: + suggestion = "%s %s %s" % (left_operand, operator, right_operand) + self.add_message("comparison-with-itself", node=node, args=(suggestion,)) + + def _check_callable_comparison(self, node): + operator = node.ops[0][0] + if operator not in COMPARISON_OPERATORS: + return + + bare_callables = (astroid.FunctionDef, astroid.BoundMethod) + left_operand, right_operand = node.left, node.ops[0][1] + # this message should be emitted only when there is comparison of bare callable + # with non bare callable. + if ( + sum( + 1 + for operand in (left_operand, right_operand) + if isinstance(utils.safe_infer(operand), bare_callables) + ) + == 1 + ): + self.add_message("comparison-with-callable", node=node) + + @utils.check_messages( + "singleton-comparison", + "misplaced-comparison-constant", + "unidiomatic-typecheck", + "literal-comparison", + "comparison-with-itself", + "comparison-with-callable", + ) + def visit_compare(self, node): + self._check_callable_comparison(node) + self._check_logical_tautology(node) + self._check_unidiomatic_typecheck(node) + # NOTE: this checker only works with binary comparisons like 'x == 42' + # but not 'x == y == 42' + if len(node.ops) != 1: + return + + left = node.left + operator, right = node.ops[0] + if operator in COMPARISON_OPERATORS and isinstance(left, astroid.Const): + self._check_misplaced_constant(node, left, right, operator) + + if operator == "==": + if isinstance(left, astroid.Const): + self._check_singleton_comparison(left, node) + elif isinstance(right, astroid.Const): + self._check_singleton_comparison(right, node) + if operator == "!=": + if isinstance(right, astroid.Const): + self._check_singleton_comparison(right, node, negative_check=True) + if operator in ("is", "is not"): + self._check_literal_comparison(right, node) + + def _check_unidiomatic_typecheck(self, node): + operator, right = node.ops[0] + if operator in TYPECHECK_COMPARISON_OPERATORS: + left = node.left + if _is_one_arg_pos_call(left): + self._check_type_x_is_y(node, left, operator, right) + + def _check_type_x_is_y(self, node, left, operator, right): + """Check for expressions like type(x) == Y.""" + left_func = utils.safe_infer(left.func) + if not ( + isinstance(left_func, astroid.ClassDef) and left_func.qname() == TYPE_QNAME + ): + return + + if operator in ("is", "is not") and _is_one_arg_pos_call(right): + right_func = utils.safe_infer(right.func) + if ( + isinstance(right_func, astroid.ClassDef) + and right_func.qname() == TYPE_QNAME + ): + # type(x) == type(a) + right_arg = utils.safe_infer(right.args[0]) + if not isinstance(right_arg, LITERAL_NODE_TYPES): + # not e.g. type(x) == type([]) + return + self.add_message("unidiomatic-typecheck", node=node) + + +def register(linter): + """required method to auto register this checker""" + linter.register_checker(BasicErrorChecker(linter)) + linter.register_checker(BasicChecker(linter)) + linter.register_checker(NameChecker(linter)) + linter.register_checker(DocStringChecker(linter)) + linter.register_checker(PassChecker(linter)) + linter.register_checker(ComparisonChecker(linter)) |