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982 lines
42 KiB
Python
982 lines
42 KiB
Python
# Copyright (c) 2003-2014 LOGILAB S.A. (Paris, FRANCE).
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# http://www.logilab.fr/ -- mailto:contact@logilab.fr
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""classes checker for Python code
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"""
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from __future__ import generators
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import sys
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from collections import defaultdict
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import astroid
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from astroid import YES, Instance, are_exclusive, AssAttr, Class
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from astroid.bases import Generator, BUILTINS
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from astroid.inference import InferenceContext
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from pylint.interfaces import IAstroidChecker
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from pylint.checkers import BaseChecker
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from pylint.checkers.utils import (
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PYMETHODS, overrides_a_method, check_messages, is_attr_private,
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is_attr_protected, node_frame_class, safe_infer, is_builtin_object,
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decorated_with_property, unimplemented_abstract_methods)
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import six
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if sys.version_info >= (3, 0):
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NEXT_METHOD = '__next__'
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else:
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NEXT_METHOD = 'next'
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ITER_METHODS = ('__iter__', '__getitem__')
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def _called_in_methods(func, klass, methods):
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""" Check if the func was called in any of the given methods,
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belonging to the *klass*. Returns True if so, False otherwise.
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"""
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if not isinstance(func, astroid.Function):
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return False
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for method in methods:
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try:
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infered = klass.getattr(method)
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except astroid.NotFoundError:
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continue
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for infer_method in infered:
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for callfunc in infer_method.nodes_of_class(astroid.CallFunc):
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try:
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bound = next(callfunc.func.infer())
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except (astroid.InferenceError, StopIteration):
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continue
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if not isinstance(bound, astroid.BoundMethod):
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continue
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func_obj = bound._proxied
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if isinstance(func_obj, astroid.UnboundMethod):
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func_obj = func_obj._proxied
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if func_obj.name == func.name:
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return True
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return False
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def class_is_abstract(node):
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"""return true if the given class node should be considered as an abstract
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class
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"""
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for method in node.methods():
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if method.parent.frame() is node:
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if method.is_abstract(pass_is_abstract=False):
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return True
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return False
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def _is_attribute_property(name, klass):
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""" Check if the given attribute *name* is a property
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in the given *klass*.
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It will look for `property` calls or for functions
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with the given name, decorated by `property` or `property`
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subclasses.
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Returns ``True`` if the name is a property in the given klass,
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``False`` otherwise.
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"""
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try:
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attributes = klass.getattr(name)
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except astroid.NotFoundError:
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return False
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property_name = "{0}.property".format(BUILTINS)
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for attr in attributes:
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try:
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infered = next(attr.infer())
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except astroid.InferenceError:
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continue
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if (isinstance(infered, astroid.Function) and
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decorated_with_property(infered)):
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return True
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if infered.pytype() == property_name:
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return True
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return False
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MSGS = {
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'F0202': ('Unable to check methods signature (%s / %s)',
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'method-check-failed',
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'Used when Pylint has been unable to check methods signature \
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compatibility for an unexpected reason. Please report this kind \
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if you don\'t make sense of it.'),
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'E0202': ('An attribute defined in %s line %s hides this method',
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'method-hidden',
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'Used when a class defines a method which is hidden by an '
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'instance attribute from an ancestor class or set by some '
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'client code.'),
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'E0203': ('Access to member %r before its definition line %s',
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'access-member-before-definition',
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'Used when an instance member is accessed before it\'s actually\
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assigned.'),
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'W0201': ('Attribute %r defined outside __init__',
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'attribute-defined-outside-init',
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'Used when an instance attribute is defined outside the __init__\
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method.'),
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'W0212': ('Access to a protected member %s of a client class', # E0214
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'protected-access',
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'Used when a protected member (i.e. class member with a name \
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beginning with an underscore) is access outside the class or a \
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descendant of the class where it\'s defined.'),
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'E0211': ('Method has no argument',
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'no-method-argument',
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'Used when a method which should have the bound instance as \
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first argument has no argument defined.'),
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'E0213': ('Method should have "self" as first argument',
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'no-self-argument',
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'Used when a method has an attribute different the "self" as\
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first argument. This is considered as an error since this is\
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a so common convention that you shouldn\'t break it!'),
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'C0202': ('Class method %s should have %s as first argument', # E0212
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'bad-classmethod-argument',
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'Used when a class method has a first argument named differently '
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'than the value specified in valid-classmethod-first-arg option '
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'(default to "cls"), recommended to easily differentiate them '
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'from regular instance methods.'),
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'C0203': ('Metaclass method %s should have %s as first argument', # E0214
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'bad-mcs-method-argument',
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'Used when a metaclass method has a first agument named '
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'differently than the value specified in valid-classmethod-first'
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'-arg option (default to "cls"), recommended to easily '
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'differentiate them from regular instance methods.'),
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'C0204': ('Metaclass class method %s should have %s as first argument',
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'bad-mcs-classmethod-argument',
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'Used when a metaclass class method has a first argument named '
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'differently than the value specified in valid-metaclass-'
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'classmethod-first-arg option (default to "mcs"), recommended to '
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'easily differentiate them from regular instance methods.'),
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'W0211': ('Static method with %r as first argument',
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'bad-staticmethod-argument',
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'Used when a static method has "self" or a value specified in '
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'valid-classmethod-first-arg option or '
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'valid-metaclass-classmethod-first-arg option as first argument.'
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),
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'R0201': ('Method could be a function',
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'no-self-use',
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'Used when a method doesn\'t use its bound instance, and so could\
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be written as a function.'
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),
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'E0221': ('Interface resolved to %s is not a class',
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'interface-is-not-class',
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'Used when a class claims to implement an interface which is not \
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a class.'),
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'E0222': ('Missing method %r from %s interface',
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'missing-interface-method',
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'Used when a method declared in an interface is missing from a \
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class implementing this interface'),
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'W0221': ('Arguments number differs from %s %r method',
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'arguments-differ',
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'Used when a method has a different number of arguments than in \
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the implemented interface or in an overridden method.'),
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'W0222': ('Signature differs from %s %r method',
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'signature-differs',
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'Used when a method signature is different than in the \
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implemented interface or in an overridden method.'),
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'W0223': ('Method %r is abstract in class %r but is not overridden',
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'abstract-method',
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'Used when an abstract method (i.e. raise NotImplementedError) is \
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not overridden in concrete class.'
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),
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'F0220': ('failed to resolve interfaces implemented by %s (%s)', # W0224
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'unresolved-interface',
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'Used when a Pylint as failed to find interfaces implemented by \
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a class'),
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'W0231': ('__init__ method from base class %r is not called',
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'super-init-not-called',
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'Used when an ancestor class method has an __init__ method \
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which is not called by a derived class.'),
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'W0232': ('Class has no __init__ method',
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'no-init',
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'Used when a class has no __init__ method, neither its parent \
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classes.'),
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'W0233': ('__init__ method from a non direct base class %r is called',
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'non-parent-init-called',
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'Used when an __init__ method is called on a class which is not \
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in the direct ancestors for the analysed class.'),
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'W0234': ('__iter__ returns non-iterator',
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'non-iterator-returned',
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'Used when an __iter__ method returns something which is not an \
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iterable (i.e. has no `%s` method)' % NEXT_METHOD),
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'E0235': ('__exit__ must accept 3 arguments: type, value, traceback',
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'bad-context-manager',
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'Used when the __exit__ special method, belonging to a \
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context manager, does not accept 3 arguments \
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(type, value, traceback).'),
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'E0236': ('Invalid object %r in __slots__, must contain '
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'only non empty strings',
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'invalid-slots-object',
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'Used when an invalid (non-string) object occurs in __slots__.'),
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'E0237': ('Assigning to attribute %r not defined in class slots',
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'assigning-non-slot',
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'Used when assigning to an attribute not defined '
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'in the class slots.'),
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'E0238': ('Invalid __slots__ object',
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'invalid-slots',
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'Used when an invalid __slots__ is found in class. '
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'Only a string, an iterable or a sequence is permitted.'),
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'E0239': ('Inheriting %r, which is not a class.',
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'inherit-non-class',
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'Used when a class inherits from something which is not a '
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'class.'),
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}
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class ClassChecker(BaseChecker):
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"""checks for :
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* methods without self as first argument
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* overridden methods signature
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* access only to existent members via self
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* attributes not defined in the __init__ method
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* supported interfaces implementation
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* unreachable code
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"""
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__implements__ = (IAstroidChecker,)
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# configuration section name
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name = 'classes'
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# messages
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msgs = MSGS
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priority = -2
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# configuration options
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options = (('ignore-iface-methods',
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{'default' : (#zope interface
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'isImplementedBy', 'deferred', 'extends', 'names',
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'namesAndDescriptions', 'queryDescriptionFor', 'getBases',
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'getDescriptionFor', 'getDoc', 'getName', 'getTaggedValue',
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'getTaggedValueTags', 'isEqualOrExtendedBy', 'setTaggedValue',
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'isImplementedByInstancesOf',
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# twisted
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'adaptWith',
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# logilab.common interface
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'is_implemented_by'),
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'type' : 'csv',
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'metavar' : '<method names>',
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'help' : 'List of interface methods to ignore, \
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separated by a comma. This is used for instance to not check methods defines \
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in Zope\'s Interface base class.'}
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),
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('defining-attr-methods',
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{'default' : ('__init__', '__new__', 'setUp'),
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'type' : 'csv',
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'metavar' : '<method names>',
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'help' : 'List of method names used to declare (i.e. assign) \
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instance attributes.'}
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),
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('valid-classmethod-first-arg',
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{'default' : ('cls',),
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'type' : 'csv',
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'metavar' : '<argument names>',
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'help' : 'List of valid names for the first argument in \
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a class method.'}
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),
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('valid-metaclass-classmethod-first-arg',
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{'default' : ('mcs',),
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'type' : 'csv',
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'metavar' : '<argument names>',
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'help' : 'List of valid names for the first argument in \
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a metaclass class method.'}
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),
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('exclude-protected',
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{
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'default': (
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# namedtuple public API.
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'_asdict', '_fields', '_replace', '_source', '_make'),
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'type': 'csv',
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'metavar': '<protected access exclusions>',
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'help': ('List of member names, which should be excluded '
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'from the protected access warning.')}
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))
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def __init__(self, linter=None):
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BaseChecker.__init__(self, linter)
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self._accessed = []
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self._first_attrs = []
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self._meth_could_be_func = None
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def visit_class(self, node):
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"""init visit variable _accessed and check interfaces
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"""
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self._accessed.append(defaultdict(list))
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self._check_bases_classes(node)
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self._check_interfaces(node)
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# if not an interface, exception, metaclass
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if node.type == 'class':
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try:
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node.local_attr('__init__')
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except astroid.NotFoundError:
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self.add_message('no-init', args=node, node=node)
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self._check_slots(node)
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self._check_proper_bases(node)
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@check_messages('inherit-non-class')
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def _check_proper_bases(self, node):
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"""
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Detect that a class inherits something which is not
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a class or a type.
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"""
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for base in node.bases:
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ancestor = safe_infer(base)
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if ancestor in (YES, None):
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continue
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if (isinstance(ancestor, astroid.Instance) and
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ancestor.is_subtype_of('%s.type' % (BUILTINS,))):
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continue
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if not isinstance(ancestor, astroid.Class):
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self.add_message('inherit-non-class',
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args=base.as_string(), node=node)
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@check_messages('access-member-before-definition',
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'attribute-defined-outside-init')
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def leave_class(self, cnode):
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"""close a class node:
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check that instance attributes are defined in __init__ and check
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access to existent members
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"""
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# check access to existent members on non metaclass classes
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accessed = self._accessed.pop()
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if cnode.type != 'metaclass':
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self._check_accessed_members(cnode, accessed)
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# checks attributes are defined in an allowed method such as __init__
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if not self.linter.is_message_enabled('attribute-defined-outside-init'):
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return
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defining_methods = self.config.defining_attr_methods
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current_module = cnode.root()
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for attr, nodes in six.iteritems(cnode.instance_attrs):
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# skip nodes which are not in the current module and it may screw up
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# the output, while it's not worth it
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nodes = [n for n in nodes if not
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isinstance(n.statement(), (astroid.Delete, astroid.AugAssign))
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and n.root() is current_module]
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if not nodes:
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continue # error detected by typechecking
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# check if any method attr is defined in is a defining method
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if any(node.frame().name in defining_methods
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for node in nodes):
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continue
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# check attribute is defined in a parent's __init__
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for parent in cnode.instance_attr_ancestors(attr):
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attr_defined = False
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# check if any parent method attr is defined in is a defining method
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for node in parent.instance_attrs[attr]:
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if node.frame().name in defining_methods:
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attr_defined = True
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if attr_defined:
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# we're done :)
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break
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else:
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# check attribute is defined as a class attribute
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try:
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cnode.local_attr(attr)
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except astroid.NotFoundError:
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for node in nodes:
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if node.frame().name not in defining_methods:
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# If the attribute was set by a callfunc in any
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# of the defining methods, then don't emit
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# the warning.
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if _called_in_methods(node.frame(), cnode,
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defining_methods):
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continue
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self.add_message('attribute-defined-outside-init',
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args=attr, node=node)
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|
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def visit_function(self, node):
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"""check method arguments, overriding"""
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# ignore actual functions
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if not node.is_method():
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return
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klass = node.parent.frame()
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self._meth_could_be_func = True
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# check first argument is self if this is actually a method
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self._check_first_arg_for_type(node, klass.type == 'metaclass')
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if node.name == '__init__':
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self._check_init(node)
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return
|
|
# check signature if the method overloads inherited method
|
|
for overridden in klass.local_attr_ancestors(node.name):
|
|
# get astroid for the searched method
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try:
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|
meth_node = overridden[node.name]
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except KeyError:
|
|
# we have found the method but it's not in the local
|
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# dictionary.
|
|
# This may happen with astroid build from living objects
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continue
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if not isinstance(meth_node, astroid.Function):
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continue
|
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self._check_signature(node, meth_node, 'overridden')
|
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break
|
|
if node.decorators:
|
|
for decorator in node.decorators.nodes:
|
|
if isinstance(decorator, astroid.Getattr) and \
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decorator.attrname in ('getter', 'setter', 'deleter'):
|
|
# attribute affectation will call this method, not hiding it
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return
|
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if isinstance(decorator, astroid.Name) and decorator.name == 'property':
|
|
# attribute affectation will either call a setter or raise
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|
# an attribute error, anyway not hiding the function
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|
return
|
|
# check if the method is hidden by an attribute
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|
try:
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|
overridden = klass.instance_attr(node.name)[0] # XXX
|
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overridden_frame = overridden.frame()
|
|
if (isinstance(overridden_frame, astroid.Function)
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|
and overridden_frame.type == 'method'):
|
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overridden_frame = overridden_frame.parent.frame()
|
|
if (isinstance(overridden_frame, Class)
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and klass.is_subtype_of(overridden_frame.qname())):
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args = (overridden.root().name, overridden.fromlineno)
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self.add_message('method-hidden', args=args, node=node)
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except astroid.NotFoundError:
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pass
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|
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# check non-iterators in __iter__
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if node.name == '__iter__':
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self._check_iter(node)
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elif node.name == '__exit__':
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self._check_exit(node)
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def _check_slots(self, node):
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if '__slots__' not in node.locals:
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return
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for slots in node.igetattr('__slots__'):
|
|
# check if __slots__ is a valid type
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|
for meth in ITER_METHODS:
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|
try:
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slots.getattr(meth)
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|
break
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|
except astroid.NotFoundError:
|
|
continue
|
|
else:
|
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self.add_message('invalid-slots', node=node)
|
|
continue
|
|
|
|
if isinstance(slots, astroid.Const):
|
|
# a string, ignore the following checks
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continue
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|
if not hasattr(slots, 'itered'):
|
|
# we can't obtain the values, maybe a .deque?
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continue
|
|
|
|
if isinstance(slots, astroid.Dict):
|
|
values = [item[0] for item in slots.items]
|
|
else:
|
|
values = slots.itered()
|
|
if values is YES:
|
|
return
|
|
|
|
for elt in values:
|
|
try:
|
|
self._check_slots_elt(elt)
|
|
except astroid.InferenceError:
|
|
continue
|
|
|
|
def _check_slots_elt(self, elt):
|
|
for infered in elt.infer():
|
|
if infered is YES:
|
|
continue
|
|
if (not isinstance(infered, astroid.Const) or
|
|
not isinstance(infered.value, six.string_types)):
|
|
self.add_message('invalid-slots-object',
|
|
args=infered.as_string(),
|
|
node=elt)
|
|
continue
|
|
if not infered.value:
|
|
self.add_message('invalid-slots-object',
|
|
args=infered.as_string(),
|
|
node=elt)
|
|
|
|
def _check_iter(self, node):
|
|
try:
|
|
infered = node.infer_call_result(node)
|
|
except astroid.InferenceError:
|
|
return
|
|
|
|
for infered_node in infered:
|
|
if (infered_node is YES
|
|
or isinstance(infered_node, Generator)):
|
|
continue
|
|
if isinstance(infered_node, astroid.Instance):
|
|
try:
|
|
infered_node.local_attr(NEXT_METHOD)
|
|
except astroid.NotFoundError:
|
|
self.add_message('non-iterator-returned',
|
|
node=node)
|
|
break
|
|
|
|
def _check_exit(self, node):
|
|
positional = sum(1 for arg in node.args.args if arg.name != 'self')
|
|
if positional < 3 and not node.args.vararg:
|
|
self.add_message('bad-context-manager',
|
|
node=node)
|
|
elif positional > 3:
|
|
self.add_message('bad-context-manager',
|
|
node=node)
|
|
|
|
def leave_function(self, node):
|
|
"""on method node, check if this method couldn't be a function
|
|
|
|
ignore class, static and abstract methods, initializer,
|
|
methods overridden from a parent class and any
|
|
kind of method defined in an interface for this warning
|
|
"""
|
|
if node.is_method():
|
|
if node.args.args is not None:
|
|
self._first_attrs.pop()
|
|
if not self.linter.is_message_enabled('no-self-use'):
|
|
return
|
|
class_node = node.parent.frame()
|
|
if (self._meth_could_be_func and node.type == 'method'
|
|
and not node.name in PYMETHODS
|
|
and not (node.is_abstract() or
|
|
overrides_a_method(class_node, node.name))
|
|
and class_node.type != 'interface'):
|
|
self.add_message('no-self-use', node=node)
|
|
|
|
def visit_getattr(self, node):
|
|
"""check if the getattr is an access to a class member
|
|
if so, register it. Also check for access to protected
|
|
class member from outside its class (but ignore __special__
|
|
methods)
|
|
"""
|
|
attrname = node.attrname
|
|
# Check self
|
|
if self.is_first_attr(node):
|
|
self._accessed[-1][attrname].append(node)
|
|
return
|
|
if not self.linter.is_message_enabled('protected-access'):
|
|
return
|
|
|
|
self._check_protected_attribute_access(node)
|
|
|
|
def visit_assattr(self, node):
|
|
if isinstance(node.ass_type(), astroid.AugAssign) and self.is_first_attr(node):
|
|
self._accessed[-1][node.attrname].append(node)
|
|
self._check_in_slots(node)
|
|
|
|
def _check_in_slots(self, node):
|
|
""" Check that the given assattr node
|
|
is defined in the class slots.
|
|
"""
|
|
infered = safe_infer(node.expr)
|
|
if infered and isinstance(infered, Instance):
|
|
klass = infered._proxied
|
|
if '__slots__' not in klass.locals or not klass.newstyle:
|
|
return
|
|
|
|
slots = klass.slots()
|
|
if slots is None:
|
|
return
|
|
# If any ancestor doesn't use slots, the slots
|
|
# defined for this class are superfluous.
|
|
if any('__slots__' not in ancestor.locals and
|
|
ancestor.name != 'object'
|
|
for ancestor in klass.ancestors()):
|
|
return
|
|
|
|
if not any(slot.value == node.attrname for slot in slots):
|
|
# If we have a '__dict__' in slots, then
|
|
# assigning any name is valid.
|
|
if not any(slot.value == '__dict__' for slot in slots):
|
|
if _is_attribute_property(node.attrname, klass):
|
|
# Properties circumvent the slots mechanism,
|
|
# so we should not emit a warning for them.
|
|
return
|
|
self.add_message('assigning-non-slot',
|
|
args=(node.attrname, ), node=node)
|
|
|
|
@check_messages('protected-access')
|
|
def visit_assign(self, assign_node):
|
|
node = assign_node.targets[0]
|
|
if not isinstance(node, AssAttr):
|
|
return
|
|
|
|
if self.is_first_attr(node):
|
|
return
|
|
|
|
self._check_protected_attribute_access(node)
|
|
|
|
def _check_protected_attribute_access(self, node):
|
|
'''Given an attribute access node (set or get), check if attribute
|
|
access is legitimate. Call _check_first_attr with node before calling
|
|
this method. Valid cases are:
|
|
* self._attr in a method or cls._attr in a classmethod. Checked by
|
|
_check_first_attr.
|
|
* Klass._attr inside "Klass" class.
|
|
* Klass2._attr inside "Klass" class when Klass2 is a base class of
|
|
Klass.
|
|
'''
|
|
attrname = node.attrname
|
|
|
|
if (is_attr_protected(attrname) and
|
|
attrname not in self.config.exclude_protected):
|
|
|
|
klass = node_frame_class(node)
|
|
|
|
# XXX infer to be more safe and less dirty ??
|
|
# in classes, check we are not getting a parent method
|
|
# through the class object or through super
|
|
callee = node.expr.as_string()
|
|
|
|
# We are not in a class, no remaining valid case
|
|
if klass is None:
|
|
self.add_message('protected-access', node=node, args=attrname)
|
|
return
|
|
|
|
# If the expression begins with a call to super, that's ok.
|
|
if isinstance(node.expr, astroid.CallFunc) and \
|
|
isinstance(node.expr.func, astroid.Name) and \
|
|
node.expr.func.name == 'super':
|
|
return
|
|
|
|
# We are in a class, one remaining valid cases, Klass._attr inside
|
|
# Klass
|
|
if not (callee == klass.name or callee in klass.basenames):
|
|
# Detect property assignments in the body of the class.
|
|
# This is acceptable:
|
|
#
|
|
# class A:
|
|
# b = property(lambda: self._b)
|
|
|
|
stmt = node.parent.statement()
|
|
try:
|
|
if (isinstance(stmt, astroid.Assign) and
|
|
(stmt in klass.body or klass.parent_of(stmt)) and
|
|
isinstance(stmt.value, astroid.CallFunc) and
|
|
isinstance(stmt.value.func, astroid.Name) and
|
|
stmt.value.func.name == 'property' and
|
|
is_builtin_object(next(stmt.value.func.infer(), None))):
|
|
return
|
|
except astroid.InferenceError:
|
|
pass
|
|
self.add_message('protected-access', node=node, args=attrname)
|
|
|
|
def visit_name(self, node):
|
|
"""check if the name handle an access to a class member
|
|
if so, register it
|
|
"""
|
|
if self._first_attrs and (node.name == self._first_attrs[-1] or
|
|
not self._first_attrs[-1]):
|
|
self._meth_could_be_func = False
|
|
|
|
def _check_accessed_members(self, node, accessed):
|
|
"""check that accessed members are defined"""
|
|
# XXX refactor, probably much simpler now that E0201 is in type checker
|
|
for attr, nodes in six.iteritems(accessed):
|
|
# deactivate "except doesn't do anything", that's expected
|
|
# pylint: disable=W0704
|
|
try:
|
|
# is it a class attribute ?
|
|
node.local_attr(attr)
|
|
# yes, stop here
|
|
continue
|
|
except astroid.NotFoundError:
|
|
pass
|
|
# is it an instance attribute of a parent class ?
|
|
try:
|
|
next(node.instance_attr_ancestors(attr))
|
|
# yes, stop here
|
|
continue
|
|
except StopIteration:
|
|
pass
|
|
# is it an instance attribute ?
|
|
try:
|
|
defstmts = node.instance_attr(attr)
|
|
except astroid.NotFoundError:
|
|
pass
|
|
else:
|
|
# filter out augment assignment nodes
|
|
defstmts = [stmt for stmt in defstmts if stmt not in nodes]
|
|
if not defstmts:
|
|
# only augment assignment for this node, no-member should be
|
|
# triggered by the typecheck checker
|
|
continue
|
|
# filter defstmts to only pick the first one when there are
|
|
# several assignments in the same scope
|
|
scope = defstmts[0].scope()
|
|
defstmts = [stmt for i, stmt in enumerate(defstmts)
|
|
if i == 0 or stmt.scope() is not scope]
|
|
# if there are still more than one, don't attempt to be smarter
|
|
# than we can be
|
|
if len(defstmts) == 1:
|
|
defstmt = defstmts[0]
|
|
# check that if the node is accessed in the same method as
|
|
# it's defined, it's accessed after the initial assignment
|
|
frame = defstmt.frame()
|
|
lno = defstmt.fromlineno
|
|
for _node in nodes:
|
|
if _node.frame() is frame and _node.fromlineno < lno \
|
|
and not are_exclusive(_node.statement(), defstmt,
|
|
('AttributeError', 'Exception', 'BaseException')):
|
|
self.add_message('access-member-before-definition',
|
|
node=_node, args=(attr, lno))
|
|
|
|
def _check_first_arg_for_type(self, node, metaclass=0):
|
|
"""check the name of first argument, expect:
|
|
|
|
* 'self' for a regular method
|
|
* 'cls' for a class method or a metaclass regular method (actually
|
|
valid-classmethod-first-arg value)
|
|
* 'mcs' for a metaclass class method (actually
|
|
valid-metaclass-classmethod-first-arg)
|
|
* not one of the above for a static method
|
|
"""
|
|
# don't care about functions with unknown argument (builtins)
|
|
if node.args.args is None:
|
|
return
|
|
first_arg = node.args.args and node.argnames()[0]
|
|
self._first_attrs.append(first_arg)
|
|
first = self._first_attrs[-1]
|
|
# static method
|
|
if node.type == 'staticmethod':
|
|
if (first_arg == 'self' or
|
|
first_arg in self.config.valid_classmethod_first_arg or
|
|
first_arg in self.config.valid_metaclass_classmethod_first_arg):
|
|
self.add_message('bad-staticmethod-argument', args=first, node=node)
|
|
return
|
|
self._first_attrs[-1] = None
|
|
# class / regular method with no args
|
|
elif not node.args.args:
|
|
self.add_message('no-method-argument', node=node)
|
|
# metaclass
|
|
elif metaclass:
|
|
# metaclass __new__ or classmethod
|
|
if node.type == 'classmethod':
|
|
self._check_first_arg_config(
|
|
first,
|
|
self.config.valid_metaclass_classmethod_first_arg, node,
|
|
'bad-mcs-classmethod-argument', node.name)
|
|
# metaclass regular method
|
|
else:
|
|
self._check_first_arg_config(
|
|
first,
|
|
self.config.valid_classmethod_first_arg, node,
|
|
'bad-mcs-method-argument',
|
|
node.name)
|
|
# regular class
|
|
else:
|
|
# class method
|
|
if node.type == 'classmethod':
|
|
self._check_first_arg_config(
|
|
first,
|
|
self.config.valid_classmethod_first_arg, node,
|
|
'bad-classmethod-argument',
|
|
node.name)
|
|
# regular method without self as argument
|
|
elif first != 'self':
|
|
self.add_message('no-self-argument', node=node)
|
|
|
|
def _check_first_arg_config(self, first, config, node, message,
|
|
method_name):
|
|
if first not in config:
|
|
if len(config) == 1:
|
|
valid = repr(config[0])
|
|
else:
|
|
valid = ', '.join(repr(v) for v in config[:-1])
|
|
valid = '%s or %r' % (valid, config[-1])
|
|
self.add_message(message, args=(method_name, valid), node=node)
|
|
|
|
def _check_bases_classes(self, node):
|
|
"""check that the given class node implements abstract methods from
|
|
base classes
|
|
"""
|
|
def is_abstract(method):
|
|
return method.is_abstract(pass_is_abstract=False)
|
|
|
|
# check if this class abstract
|
|
if class_is_abstract(node):
|
|
return
|
|
|
|
methods = sorted(
|
|
unimplemented_abstract_methods(node, is_abstract).items(),
|
|
key=lambda item: item[0],
|
|
)
|
|
for name, method in methods:
|
|
owner = method.parent.frame()
|
|
if owner is node:
|
|
continue
|
|
# owner is not this class, it must be a parent class
|
|
# check that the ancestor's method is not abstract
|
|
if name in node.locals:
|
|
# it is redefined as an attribute or with a descriptor
|
|
continue
|
|
self.add_message('abstract-method', node=node,
|
|
args=(name, owner.name))
|
|
|
|
def _check_interfaces(self, node):
|
|
"""check that the given class node really implements declared
|
|
interfaces
|
|
"""
|
|
e0221_hack = [False]
|
|
def iface_handler(obj):
|
|
"""filter interface objects, it should be classes"""
|
|
if not isinstance(obj, astroid.Class):
|
|
e0221_hack[0] = True
|
|
self.add_message('interface-is-not-class', node=node,
|
|
args=(obj.as_string(),))
|
|
return False
|
|
return True
|
|
ignore_iface_methods = self.config.ignore_iface_methods
|
|
try:
|
|
for iface in node.interfaces(handler_func=iface_handler):
|
|
for imethod in iface.methods():
|
|
name = imethod.name
|
|
if name.startswith('_') or name in ignore_iface_methods:
|
|
# don't check method beginning with an underscore,
|
|
# usually belonging to the interface implementation
|
|
continue
|
|
# get class method astroid
|
|
try:
|
|
method = node_method(node, name)
|
|
except astroid.NotFoundError:
|
|
self.add_message('missing-interface-method',
|
|
args=(name, iface.name),
|
|
node=node)
|
|
continue
|
|
# ignore inherited methods
|
|
if method.parent.frame() is not node:
|
|
continue
|
|
# check signature
|
|
self._check_signature(method, imethod,
|
|
'%s interface' % iface.name)
|
|
except astroid.InferenceError:
|
|
if e0221_hack[0]:
|
|
return
|
|
implements = Instance(node).getattr('__implements__')[0]
|
|
assignment = implements.parent
|
|
assert isinstance(assignment, astroid.Assign)
|
|
# assignment.expr can be a Name or a Tuple or whatever.
|
|
# Use as_string() for the message
|
|
# FIXME: in case of multiple interfaces, find which one could not
|
|
# be resolved
|
|
self.add_message('unresolved-interface', node=implements,
|
|
args=(node.name, assignment.value.as_string()))
|
|
|
|
def _check_init(self, node):
|
|
"""check that the __init__ method call super or ancestors'__init__
|
|
method
|
|
"""
|
|
if (not self.linter.is_message_enabled('super-init-not-called') and
|
|
not self.linter.is_message_enabled('non-parent-init-called')):
|
|
return
|
|
klass_node = node.parent.frame()
|
|
to_call = _ancestors_to_call(klass_node)
|
|
not_called_yet = dict(to_call)
|
|
for stmt in node.nodes_of_class(astroid.CallFunc):
|
|
expr = stmt.func
|
|
if not isinstance(expr, astroid.Getattr) \
|
|
or expr.attrname != '__init__':
|
|
continue
|
|
# skip the test if using super
|
|
if isinstance(expr.expr, astroid.CallFunc) and \
|
|
isinstance(expr.expr.func, astroid.Name) and \
|
|
expr.expr.func.name == 'super':
|
|
return
|
|
try:
|
|
klass = next(expr.expr.infer())
|
|
if klass is YES:
|
|
continue
|
|
# The infered klass can be super(), which was
|
|
# assigned to a variable and the `__init__` was called later.
|
|
#
|
|
# base = super()
|
|
# base.__init__(...)
|
|
|
|
if (isinstance(klass, astroid.Instance) and
|
|
isinstance(klass._proxied, astroid.Class) and
|
|
is_builtin_object(klass._proxied) and
|
|
klass._proxied.name == 'super'):
|
|
return
|
|
try:
|
|
del not_called_yet[klass]
|
|
except KeyError:
|
|
if klass not in to_call:
|
|
self.add_message('non-parent-init-called',
|
|
node=expr, args=klass.name)
|
|
except astroid.InferenceError:
|
|
continue
|
|
for klass, method in six.iteritems(not_called_yet):
|
|
if klass.name == 'object' or method.parent.name == 'object':
|
|
continue
|
|
self.add_message('super-init-not-called', args=klass.name, node=node)
|
|
|
|
def _check_signature(self, method1, refmethod, class_type):
|
|
"""check that the signature of the two given methods match
|
|
|
|
class_type is in 'class', 'interface'
|
|
"""
|
|
if not (isinstance(method1, astroid.Function)
|
|
and isinstance(refmethod, astroid.Function)):
|
|
self.add_message('method-check-failed',
|
|
args=(method1, refmethod), node=method1)
|
|
return
|
|
# don't care about functions with unknown argument (builtins)
|
|
if method1.args.args is None or refmethod.args.args is None:
|
|
return
|
|
# if we use *args, **kwargs, skip the below checks
|
|
if method1.args.vararg or method1.args.kwarg:
|
|
return
|
|
if is_attr_private(method1.name):
|
|
return
|
|
if len(method1.args.args) != len(refmethod.args.args):
|
|
self.add_message('arguments-differ',
|
|
args=(class_type, method1.name),
|
|
node=method1)
|
|
elif len(method1.args.defaults) < len(refmethod.args.defaults):
|
|
self.add_message('signature-differs',
|
|
args=(class_type, method1.name),
|
|
node=method1)
|
|
|
|
def is_first_attr(self, node):
|
|
"""Check that attribute lookup name use first attribute variable name
|
|
(self for method, cls for classmethod and mcs for metaclass).
|
|
"""
|
|
return self._first_attrs and isinstance(node.expr, astroid.Name) and \
|
|
node.expr.name == self._first_attrs[-1]
|
|
|
|
def _ancestors_to_call(klass_node, method='__init__'):
|
|
"""return a dictionary where keys are the list of base classes providing
|
|
the queried method, and so that should/may be called from the method node
|
|
"""
|
|
to_call = {}
|
|
for base_node in klass_node.ancestors(recurs=False):
|
|
try:
|
|
to_call[base_node] = next(base_node.igetattr(method))
|
|
except astroid.InferenceError:
|
|
continue
|
|
return to_call
|
|
|
|
|
|
def node_method(node, method_name):
|
|
"""get astroid for <method_name> on the given class node, ensuring it
|
|
is a Function node
|
|
"""
|
|
for n in node.local_attr(method_name):
|
|
if isinstance(n, astroid.Function):
|
|
return n
|
|
raise astroid.NotFoundError(method_name)
|
|
|
|
def register(linter):
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"""required method to auto register this checker """
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linter.register_checker(ClassChecker(linter))
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