FIX: is_hybrid_property method attribute error on deeper relationship columns on filters

[WhatmoreCB]

is_hybrid_property method failing when called by scaffold_filters method on ModelView class when adding a grandchild column name to column_filters e.g column_filters = ('children.grandchild.name')

Added additional if statement to convert the last_model class back to a sqlalchemy model class

Noticed that this issue was raised on another pull request but poster hasn't responded: #2390

maintainer asks to add a test that fails without the changes and that passes with the changes, upon writing a test I found that it's due to the backref arg when defining relationships in the model, not sure where to put the test file so will add as an additional comment

[WhatmoreCB]

from sqlalchemy import Column, Integer, String, ForeignKey
from sqlalchemy.ext.declarative import as_declarative
from sqlalchemy.orm import relationship, backref, configure_mappers
from sqlalchemy.ext.hybrid import hybrid_property
import flask_admin.contrib.sqla.tools as tools

import types

try:
# Attempt _class_resolver import from SQLALchemy 1.4/2.0 module architecture.
from sqlalchemy.orm.clsregistry import _class_resolver
except ImportError:
# If 1.4/2.0 module import fails, fall back to <1.3.x architecture.
from sqlalchemy.ext.declarative.clsregistry import _class_resolver # type: ignore

from flask_admin._compat import string_types

@as_declarative()
class Base:
pass

class GrandChild(Base):
tablename = 'GrandChild'
id = Column(Integer, primary_key=True)
name = Column(String)

child_id = Column(Integer, ForeignKey('Child.id'))
child = relationship('Child', foreign_keys=[child_id], backref=backref('grandchild'))

@hybrid_property
def upper_name(self):
    return self.name.upper() if self.name else None

class Child(Base):
tablename = 'Child'
id = Column(Integer, primary_key=True)
parent_id = Column(Integer, ForeignKey('Parent.id'))
parent = relationship('Parent', foreign_keys=[parent_id], backref=backref('children'))

class Parent(Base):
tablename = 'Parent'
id = Column(Integer, primary_key=True)

def test_is_hybrid_property_deep_relationship():

# Existing method
try:
    result = tools.is_hybrid_property(Parent, "children.grandchild.upper_name")
except AttributeError:
    result = False

assert result is False

def is_hybrid_property(model, attr_name):
    if isinstance(attr_name, string_types):
        names = attr_name.split('.')
        last_model = model
        for i in range(len(names) - 1):
            attr = getattr(last_model, names[i])
            if tools.is_association_proxy(attr):
                attr = attr.remote_attr
            last_model = attr.property.argument
            if isinstance(last_model, string_types):
                last_model = attr.property._clsregistry_resolve_name(last_model)()
            elif isinstance(last_model, _class_resolver):
                last_model = model._decl_class_registry[last_model.arg]
            elif isinstance(last_model, (types.FunctionType, types.MethodType)):
                last_model = last_model()
            elif getattr(last_model, 'is_mapper'):
                last_model = last_model.class_
        last_name = names[-1]
        return last_name in tools.get_hybrid_properties(last_model)
    else:
        return attr_name.name in tools.get_hybrid_properties(model)
    
# This should return True if the function correctly resolves deep relationships
try:
    result = is_hybrid_property(Parent, "children.grandchild.upper_name")
except AttributeError:
    result = False

assert result is True

if name == 'main':
configure_mappers()
test_is_hybrid_property_deep_relationship()

[ElLorans]

Thanks for your PR.

1. Can you run tox -e style and commit the changes? If you do pre-commit install you won't need to do that anymore.
2. Can you try fixing the formatting in your example?

EDIT: I also see your example is directly on flask-admin internals, which is great for the tests. Do you have by any chance a test also showing how this would work on a flask-admin app?