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"""Models.""" from astroid import Const from astroid.nodes import Assign, AssignName, ClassDef, FunctionDef from pylint.checkers import BaseChecker from pylint.checkers.utils import check_messages from pylint.interfaces import IAstroidChecker
from pylint_django.__pkginfo__ import BASE_ID from pylint_django.utils import PY3, node_is_subclass
MESSAGES = { f"E{BASE_ID}01": ( "__unicode__ on a model must be callable (%s)", "model-unicode-not-callable", "Django models require a callable __unicode__ method", ), f"W{BASE_ID}01": ( "No __unicode__ method on model (%s)", "model-missing-unicode", "Django models should implement a __unicode__ method for string representation", ), f"W{BASE_ID}02": ( "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", ), f"W{BASE_ID}03": ( "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
def _has_python_2_unicode_compatible_decorator(node): if node.decorators is None: return False
for decorator in node.decorators.nodes: if getattr(decorator, "name", None) == "python_2_unicode_compatible": return True
return False
def _is_unicode_or_str_in_python_2_compatibility(method): if method.name == "__unicode__": return True
if method.name == "__str__" and _has_python_2_unicode_compatible_decorator(method.parent): return True
return False
class ModelChecker(BaseChecker): """Django model checker."""
__implements__ = IAstroidChecker
name = "django-model-checker" msgs = MESSAGES
@check_messages("model-missing-unicode") 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 = grandchild.inferred()[0]
if assigned.callable(): return
self.add_message(f"E{BASE_ID}01", args=node.name, node=node) return
if isinstance(child, FunctionDef) and child.name == "__unicode__": if PY3: self.add_message(f"W{BASE_ID}02", args=node.name, node=node) return
# if we get here, then we have no __unicode__ method directly on the class itself
# a different warning is emitted if a parent declares __unicode__ for method in node.methods(): if method.parent != node and _is_unicode_or_str_in_python_2_compatibility(method): # this happens if a parent declares the unicode method but # this node does not self.add_message(f"W{BASE_ID}03", args=node.name, node=node) return
# if the Django compatibility decorator is used then we don't emit a warning # see https://github.com/PyCQA/pylint-django/issues/10 if _has_python_2_unicode_compatible_decorator(node): return
if PY3: return
self.add_message(f"W{BASE_ID}01", args=node.name, node=node)
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