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"""Models."""
from astroid import Const
from pylint_django.compat import ClassDef, FunctionDef, inferred, AssignName
from astroid.nodes import Assign
from pylint.interfaces import IAstroidChecker
from pylint.checkers.utils import check_messages
from pylint.checkers import BaseChecker
from pylint.__pkginfo__ import numversion as PYLINT_VERSION
from pylint_django.__pkginfo__ import BASE_ID
from pylint_django.utils import node_is_subclass, PY3
MESSAGES = {
'E%d01' % BASE_ID: ("__unicode__ on a model must be callable (%s)",
'model-unicode-not-callable',
"Django models require a callable __unicode__ method"),
'W%d01' % BASE_ID: ("No __unicode__ method on model (%s)",
'model-missing-unicode',
"Django models should implement a __unicode__ method for string representation"),
'W%d02' % BASE_ID: ("Found __unicode__ method on model (%s). Python3 uses __str__.",
'model-has-unicode',
"Django models should not implement a __unicode__ "
"method for string representation when using Python3"),
'W%d03' % BASE_ID: ("Model does not explicitly define __unicode__ (%s)",
'model-no-explicit-unicode',
"Django models should implement a __unicode__ method for string representation. "
"A parent class of this model does, but ideally all models should be explicit.")
}
def _is_meta_with_abstract(node):
if isinstance(node, ClassDef) and node.name == 'Meta':
for meta_child in node.get_children():
if not isinstance(meta_child, Assign):
continue
if not meta_child.targets[0].name == 'abstract':
continue
if not isinstance(meta_child.value, Const):
continue
# TODO: handle tuple assignment?
# eg:
# abstract, something_else = True, 1
if meta_child.value.value:
# this class is abstract
return True
return False
class ModelChecker(BaseChecker):
"""Django model checker."""
__implements__ = IAstroidChecker
name = 'django-model-checker'
msgs = MESSAGES
# XXX: there's a bug in pylint's backwards compatability logic after changing
# visit method names from visit_class to visit_classdef, see
# https://bitbucket.org/logilab/pylint/issues/711/new-node-visit-methods-not-backwards
if PYLINT_VERSION < (1, 5):
@check_messages('model-missing-unicode')
def visit_class(self, node):
return self._visit_classdef(node)
else:
@check_messages('model-missing-unicode')
def visit_classdef(self, node):
return self._visit_classdef(node)
def _visit_classdef(self, node):
"""Class visitor."""
if not node_is_subclass(node, 'django.db.models.base.Model', '.Model'):
# we only care about models
return
for child in node.get_children():
if _is_meta_with_abstract(child):
return
if isinstance(child, Assign):
grandchildren = list(child.get_children())
if not isinstance(grandchildren[0], AssignName):
continue
name = grandchildren[0].name
if name != '__unicode__':
continue
grandchild = grandchildren[1]
assigned = inferred(grandchild)()[0]
if assigned.callable():
return
self.add_message('E%s01' % BASE_ID, args=node.name, node=node)
return
if isinstance(child, FunctionDef) and child.name == '__unicode__':
if PY3:
self.add_message('W%s02' % BASE_ID, args=node.name, node=node)
return
# if we get here, then we have no __unicode__ method directly on the class itself
if PY3:
return
# a different warning is emitted if a parent declares __unicode__
for method in node.methods():
if method.name == '__unicode__':
# this happens if a parent declares the unicode method but
# this node does not
self.add_message('W%s03' % BASE_ID, args=node.name, node=node)
return
# if the Django compatibility decorator is used then we don't emit a warning
# see https://github.com/landscapeio/pylint-django/issues/10
if node.decorators is not None:
for decorator in node.decorators.nodes:
if getattr(decorator, 'name', None) == 'python_2_unicode_compatible':
return
self.add_message('W%s01' % BASE_ID, args=node.name, node=node)
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