180 lines
7.2 KiB
Python
180 lines
7.2 KiB
Python
# Copyright (c) 2006, 2008-2011, 2013-2014 LOGILAB S.A. (Paris, FRANCE) <contact@logilab.fr>
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# Copyright (c) 2013-2016 Claudiu Popa <pcmanticore@gmail.com>
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# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
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"""check for new / old style related problems
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"""
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import sys
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import astroid
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from pylint.interfaces import IAstroidChecker, INFERENCE, INFERENCE_FAILURE, HIGH
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from pylint.checkers import BaseChecker
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from pylint.checkers.utils import (
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check_messages,
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node_frame_class,
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has_known_bases
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)
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MSGS = {
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'E1001': ('Use of __slots__ on an old style class',
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'slots-on-old-class',
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'Used when an old style class uses the __slots__ attribute.',
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{'maxversion': (3, 0)}),
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'E1002': ('Use of super on an old style class',
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'super-on-old-class',
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'Used when an old style class uses the super builtin.',
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{'maxversion': (3, 0)}),
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'E1003': ('Bad first argument %r given to super()',
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'bad-super-call',
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'Used when another argument than the current class is given as \
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first argument of the super builtin.'),
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'E1004': ('Missing argument to super()',
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'missing-super-argument',
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'Used when the super builtin didn\'t receive an \
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argument.',
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{'maxversion': (3, 0)}),
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'W1001': ('Use of "property" on an old style class',
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'property-on-old-class',
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'Used when Pylint detect the use of the builtin "property" \
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on an old style class while this is relying on new style \
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classes features.',
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{'maxversion': (3, 0)}),
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'C1001': ('Old-style class defined.',
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'old-style-class',
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'Used when a class is defined that does not inherit from another '
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'class and does not inherit explicitly from "object".',
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{'maxversion': (3, 0)})
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}
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class NewStyleConflictChecker(BaseChecker):
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"""checks for usage of new style capabilities on old style classes and
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other new/old styles conflicts problems
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* use of property, __slots__, super
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* "super" usage
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"""
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__implements__ = (IAstroidChecker,)
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# configuration section name
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name = 'newstyle'
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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 = ()
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@check_messages('slots-on-old-class', 'old-style-class')
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def visit_classdef(self, node):
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""" Check __slots__ in old style classes and old
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style class definition.
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"""
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if '__slots__' in node and not node.newstyle:
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confidence = (INFERENCE if has_known_bases(node)
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else INFERENCE_FAILURE)
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self.add_message('slots-on-old-class', node=node,
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confidence=confidence)
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# The node type could be class, exception, metaclass, or
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# interface. Presumably, the non-class-type nodes would always
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# have an explicit base class anyway.
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if not node.bases and node.type == 'class' and not node.metaclass():
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# We use confidence HIGH here because this message should only ever
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# be emitted for classes at the root of the inheritance hierarchyself.
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self.add_message('old-style-class', node=node, confidence=HIGH)
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@check_messages('property-on-old-class')
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def visit_call(self, node):
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"""check property usage"""
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parent = node.parent.frame()
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if (isinstance(parent, astroid.ClassDef) and
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not parent.newstyle and
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isinstance(node.func, astroid.Name)):
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confidence = (INFERENCE if has_known_bases(parent)
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else INFERENCE_FAILURE)
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name = node.func.name
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if name == 'property':
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self.add_message('property-on-old-class', node=node,
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confidence=confidence)
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@check_messages('super-on-old-class', 'bad-super-call', 'missing-super-argument')
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def visit_functiondef(self, node):
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"""check use of super"""
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# ignore actual functions or method within a new style class
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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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for stmt in node.nodes_of_class(astroid.Call):
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if node_frame_class(stmt) != node_frame_class(node):
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# Don't look down in other scopes.
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continue
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expr = stmt.func
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if not isinstance(expr, astroid.Attribute):
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continue
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call = expr.expr
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# skip the test if using super
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if not (isinstance(call, astroid.Call) and
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isinstance(call.func, astroid.Name) and
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call.func.name == 'super'):
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continue
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if not klass.newstyle and has_known_bases(klass):
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# super should not be used on an old style class
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self.add_message('super-on-old-class', node=node)
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else:
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# super first arg should be the class
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if not call.args:
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if sys.version_info[0] == 3:
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# unless Python 3
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continue
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else:
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self.add_message('missing-super-argument', node=call)
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continue
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# calling super(type(self), self) can lead to recursion loop
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# in derived classes
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arg0 = call.args[0]
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if isinstance(arg0, astroid.Call) and \
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isinstance(arg0.func, astroid.Name) and \
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arg0.func.name == 'type':
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self.add_message('bad-super-call', node=call, args=('type', ))
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continue
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# calling super(self.__class__, self) can lead to recursion loop
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# in derived classes
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if len(call.args) >= 2 and \
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isinstance(call.args[1], astroid.Name) and \
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call.args[1].name == 'self' and \
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isinstance(arg0, astroid.Attribute) and \
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arg0.attrname == '__class__':
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self.add_message('bad-super-call', node=call, args=('self.__class__', ))
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continue
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try:
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supcls = call.args and next(call.args[0].infer(), None)
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except astroid.InferenceError:
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continue
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if klass is not supcls:
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name = None
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# if supcls is not YES, then supcls was infered
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# and use its name. Otherwise, try to look
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# for call.args[0].name
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if supcls:
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name = supcls.name
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elif call.args and hasattr(call.args[0], 'name'):
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name = call.args[0].name
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if name:
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self.add_message('bad-super-call', node=call, args=(name, ))
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visit_asyncfunctiondef = visit_functiondef
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def register(linter):
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"""required method to auto register this checker """
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linter.register_checker(NewStyleConflictChecker(linter))
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