Test case for flask-admin/flask-admin issue #846 (and usage of PR #808)

gistfile1.txt

from flask import Flask
import sqlalchemy as sa
from sqlalchemy import orm
from sqlalchemy.ext.declarative import declarative_base

from flask.ext.admin import Admin
from flask.ext.admin.contrib import sqla


app = Flask(__name__)
engine = sa.create_engine(
    'sqlite://',
    connect_args={'check_same_thread': False},
    poolclass=sa.pool.StaticPool,
)
session = orm.scoped_session(orm.sessionmaker())

metadata = sa.MetaData()
Base = declarative_base(metadata=metadata, bind=engine)
Base.query = session.query_property()


# Create models
class A(Base):
    __tablename__ = 'a'
    __str__ = lambda s: s.name
    id = sa.Column(sa.Integer, primary_key=True)
    name = sa.Column(sa.Text)


class B(Base):
    __tablename__ = 'b'
    __str__ = lambda s: s.title
    id = sa.Column(sa.Integer, primary_key=True)
    title = sa.Column(sa.Text)
    a1_id = sa.Column(sa.Integer, sa.ForeignKey(A.id))
    a1 = sa.orm.relationship(A, foreign_keys=[a1_id])
    a2_id = sa.Column(sa.Integer, sa.ForeignKey(A.id))
    a2 = sa.orm.relationship(A, foreign_keys=[a2_id])

Base.metadata.create_all()

xyz = A(name='xyz')
bar = A(name='bar')
foobar = B(title='foobar', a1=xyz, a2=bar)
session.add(xyz)
session.add(bar)
session.add(foobar)
session.commit()


# Customized Post model admin
class BAdmin(sqla.ModelView):
    column_searchable_list = (
        # A.name,
        # Doing a search raises:
        # sqlalchemy.exc.InvalidRequestError: Could not find a FROM clause to join from.  Tried joining to a, but got: Can't determine join between 'b' and 'a'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly.
        # Using PR #808 (commit cd90dfd) doesn't give this exception, but also doesn't yield any search results

        # B.a1.name,
        # App crashes with:
        # AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with B.a1 has an attribute 'name'

        # B.a1,
        # App crashes with:
        # Exception: Invalid field B.a1: does not contains any columns.

        # 'a1.name',
        # sqlalchemy.exc.InvalidRequestError: Could not find a FROM clause to join from.  Tried joining to a, but got: Can't determine join between 'b' and 'a'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly.

        # http://localhost:5000/admin/b/?search=xyz works with PR #808 and gives the correct search result.
        # (https://github.com/flask-admin/flask-admin/pull/808, commit cd90dfd)
        'a1.name',

        # http://localhost:5000/admin/b/?search=bar does not give any results for PR #808, why is that?
        # 'a2.name',
    )

admin = Admin()
admin.init_app(app)
admin.add_view(sqla.ModelView(A, session))
admin.add_view(BAdmin(B, session))

app.run(debug=True)