from itertools import chain
from astroid import MANAGER, InferenceError, UseInferenceDefault, inference_tip, nodes
from astroid.nodes import Attribute, ClassDef
from pylint_django.utils import node_is_subclass
def is_foreignkey_in_class(node):
# is this of the form field = models.ForeignKey
if not isinstance(node.parent, nodes.Assign):
return False
if not isinstance(node.parent.parent, ClassDef):
return False
# Make sure the outfit class is the subclass of django.db.models.Model
is_in_django_model_class = node_is_subclass(node.parent.parent, "django.db.models.base.Model", ".Model")
if not is_in_django_model_class:
return False
if isinstance(node.func, Attribute):
attr = node.func.attrname
elif isinstance(node.func, nodes.Name):
attr = node.func.name
else:
return False
return attr in ("OneToOneField", "ForeignKey")
def _get_model_class_defs_from_module(module, model_name, module_name):
class_defs = []
for module_node in module.lookup(model_name)[1]:
if isinstance(module_node, nodes.ClassDef) and node_is_subclass(module_node, "django.db.models.base.Model"):
class_defs.append(module_node)
elif isinstance(module_node, nodes.ImportFrom):
imported_module = module_node.do_import_module()
class_defs.extend(_get_model_class_defs_from_module(imported_module, model_name, module_name))
return class_defs
def _module_name_from_django_model_resolution(model_name, module_name):
import django # pylint: disable=import-outside-toplevel
django.setup()
from django.apps import apps # pylint: disable=import-outside-toplevel
app = apps.get_app_config(module_name)
model = app.get_model(model_name)
return model.__module__
def infer_key_classes(node, context=None):
from django.core.exceptions import ( # pylint: disable=import-outside-toplevel
ImproperlyConfigured,
)
keyword_args = []
if node.keywords:
keyword_args = [kw.value for kw in node.keywords if kw.arg == "to"]
all_args = chain(node.args, keyword_args)
for arg in all_args:
# typically the class of the foreign key will
# be the first argument, so we'll go from left to right
if isinstance(arg, (nodes.Name, nodes.Attribute)):
try:
key_cls = None
for inferred in arg.infer(context=context):
key_cls = inferred
break
except InferenceError:
continue
else:
if key_cls is not None:
break
elif isinstance(arg, nodes.Const):
try:
# can be 'self' , 'Model' or 'app.Model'
if arg.value == "self":
module_name = ""
# for relations with `to` first parent be Keyword(arg='to')
# and we need to go deeper in parent tree to get model name
if isinstance(arg.parent, nodes.Keyword) and arg.parent.arg == "to":
model_name = arg.parent.parent.parent.parent.name
else:
model_name = arg.parent.parent.parent.name
else:
module_name, _, model_name = arg.value.rpartition(".")
except AttributeError:
break
# when ForeignKey is specified only by class name we assume that
# this class must be found in the current module
if not module_name:
current_module = node.frame()
while not isinstance(current_module, nodes.Module):
current_module = current_module.parent.frame()
module_name = current_module.name
elif not module_name.endswith("models"):
# otherwise Django allows specifying an app name first, e.g.
# ForeignKey('auth.User')
try:
module_name = _module_name_from_django_model_resolution(model_name, module_name)
except LookupError:
# If Django's model resolution fails we try to convert that to
# 'auth.models', 'User' which works nicely with the `endswith()`
# comparison below
module_name += ".models"
except ImproperlyConfigured as exep:
raise RuntimeError(
"DJANGO_SETTINGS_MODULE required for resolving ForeignKey "
"string references, see Usage section in README at "
"https://pypi.org/project/pylint-django/!"
) from exep
# ensure that module is loaded in astroid_cache, for cases when models is a package
if module_name not in MANAGER.astroid_cache:
MANAGER.ast_from_module_name(module_name)
# create list from dict_values, because it may be modified in a loop
for module in list(MANAGER.astroid_cache.values()):
# only load model classes from modules which match the module in
# which *we think* they are defined. This will prevent inferring
# other models of the same name which are found elsewhere!
if model_name in module.locals and module.name.endswith(module_name):
class_defs = _get_model_class_defs_from_module(module, model_name, module_name)
if class_defs:
return iter([class_defs[0].instantiate_class()])
else:
raise UseInferenceDefault
return iter([key_cls.instantiate_class()])
def add_transform(manager):
manager.register_transform(nodes.Call, inference_tip(infer_key_classes), is_foreignkey_in_class)
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