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# Copyright (c) 2005-2013 LOGILAB S.A. (Paris, FRANCE).
# http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
"""check for new / old style related problems
"""
import sys
import astroid
from pylint.interfaces import IAstroidChecker
from pylint.checkers import BaseChecker
from pylint.checkers.utils import check_messages
MSGS = {
'E1001': ('Use of __slots__ on an old style class',
'slots-on-old-class',
'Used when an old style class uses the __slots__ attribute.'),
'E1002': ('Use of super on an old style class',
'super-on-old-class',
'Used when an old style class uses the super builtin.'),
'E1003': ('Bad first argument %r given to super()',
'bad-super-call',
'Used when another argument than the current class is given as \
first argument of the super builtin.'),
'E1004': ('Missing argument to super()',
'missing-super-argument',
'Used when the super builtin didn\'t receive an \
argument on Python 2',
{'maxversion': (3, 0)}),
'W1001': ('Use of "property" on an old style class',
'property-on-old-class',
'Used when PyLint detect the use of the builtin "property" \
on an old style class while this is relying on new style \
classes features'),
'C1001': ('Old-style class defined.',
'old-style-class',
'Used when a class is defined that does not inherit from another'
'class and does not inherit explicitly from "object".')
}
class NewStyleConflictChecker(BaseChecker):
"""checks for usage of new style capabilities on old style classes and
other new/old styles conflicts problems
* use of property, __slots__, super
* "super" usage
"""
__implements__ = (IAstroidChecker,)
# configuration section name
name = 'newstyle'
# messages
msgs = MSGS
priority = -2
# configuration options
options = ()
@check_messages('E1001', 'C1001')
def visit_class(self, node):
"""check __slots__ usage
"""
if '__slots__' in node and not node.newstyle:
self.add_message('E1001', node=node)
# The node type could be class, exception, metaclass, or
# interface. Presumably, the non-class-type nodes would always
# have an explicit base class anyway.
if not node.bases and node.type == 'class':
self.add_message('C1001', node=node)
@check_messages('W1001')
def visit_callfunc(self, node):
"""check property usage"""
parent = node.parent.frame()
if (isinstance(parent, astroid.Class) and
not parent.newstyle and
isinstance(node.func, astroid.Name)):
name = node.func.name
if name == 'property':
self.add_message('W1001', node=node)
@check_messages('E1002', 'E1003', 'E1004')
def visit_function(self, node):
"""check use of super"""
# ignore actual functions or method within a new style class
if not node.is_method():
return
klass = node.parent.frame()
for stmt in node.nodes_of_class(astroid.CallFunc):
expr = stmt.func
if not isinstance(expr, astroid.Getattr):
continue
call = expr.expr
# skip the test if using super
if isinstance(call, astroid.CallFunc) and \
isinstance(call.func, astroid.Name) and \
call.func.name == 'super':
if not klass.newstyle:
# super should not be used on an old style class
self.add_message('E1002', node=node)
else:
# super first arg should be the class
if not call.args and sys.version_info[0] == 3:
# unless Python 3
continue
try:
supcls = (call.args and call.args[0].infer().next()
or None)
except astroid.InferenceError:
continue
if supcls is None and sys.version_info[0] == 2:
self.add_message('missing-super-argument', node=call)
continue
if klass is not supcls:
supcls = getattr(supcls, 'name', supcls)
self.add_message('E1003', node=call, args=(supcls, ))
def register(linter):
"""required method to auto register this checker """
linter.register_checker(NewStyleConflictChecker(linter))
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