From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Sun, 25 Sep 2022 18:56:22 +0000 (-0400)
Subject: warn for local-only column in remote side
X-Git-Tag: rel_2_0_0b1~44^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=29838ef584d49e5ecca08f76e4966454dc7f060f;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

warn for local-only column in remote side

A warning is emitted in ORM configurations when an explicit
:func:`_orm.remote` annotation is applied to columns that are local to the
immediate mapped class, when the referenced class does not include any of
the same table columns. Ideally this would raise an error at some point as
it's not correct from a mapping point of view.

Fixes: #7094
Fixes: #8575
Change-Id: Ia31be24aebe143161e19dc311b52c08fd5014d33
---

diff --git a/doc/build/changelog/unreleased_14/7094.rst b/doc/build/changelog/unreleased_14/7094.rst
new file mode 100644
index 0000000000..b6fb30d998
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/7094.rst
@@ -0,0 +1,9 @@
+.. change::
+    :tags: bug, orm
+    :tickets: 7094
+
+    A warning is emitted in ORM configurations when an explicit
+    :func:`_orm.remote` annotation is applied to columns that are local to the
+    immediate mapped class, when the referenced class does not include any of
+    the same table columns. Ideally this would raise an error at some point as
+    it's not correct from a mapping point of view.
diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py
index 45b9b9beaa..48d60647c0 100644
--- a/lib/sqlalchemy/orm/relationships.py
+++ b/lib/sqlalchemy/orm/relationships.py
@@ -2806,6 +2806,22 @@ class JoinCondition:
                 "condition that are on the remote side of "
                 "the relationship." % (self.prop,)
             )
+        else:
+
+            not_target = util.column_set(
+                self.parent_persist_selectable.c
+            ).difference(self.child_persist_selectable.c)
+
+            for _, rmt in self.local_remote_pairs:
+                if rmt in not_target:
+                    util.warn(
+                        "Expression %s is marked as 'remote', but these "
+                        "column(s) are local to the local side.  The "
+                        "remote() annotation is needed only for a "
+                        "self-referential relationship where both sides "
+                        "of the relationship refer to the same tables."
+                        % (rmt,)
+                    )
 
     def _check_foreign_cols(
         self, join_condition: ColumnElement[bool], primary: bool
diff --git a/test/orm/test_cycles.py b/test/orm/test_cycles.py
index 15155293fa..a23d8b735a 100644
--- a/test/orm/test_cycles.py
+++ b/test/orm/test_cycles.py
@@ -918,7 +918,6 @@ class OneToManyManyToOneTest(fixtures.MappedTest):
                 favorite=relationship(
                     Ball,
                     primaryjoin=person.c.favorite_ball_id == ball.c.id,
-                    remote_side=person.c.favorite_ball_id,
                     post_update=True,
                     _legacy_inactive_history_style=(
                         self._legacy_inactive_history_style
@@ -1036,7 +1035,6 @@ class OneToManyManyToOneTest(fixtures.MappedTest):
                 favorite=relationship(
                     Ball,
                     primaryjoin=person.c.favorite_ball_id == ball.c.id,
-                    remote_side=person.c.favorite_ball_id,
                     _legacy_inactive_history_style=(
                         self._legacy_inactive_history_style
                     ),
@@ -1096,7 +1094,6 @@ class OneToManyManyToOneTest(fixtures.MappedTest):
                 favorite=relationship(
                     Ball,
                     primaryjoin=person.c.favorite_ball_id == ball.c.id,
-                    remote_side=person.c.favorite_ball_id,
                     _legacy_inactive_history_style=(
                         self._legacy_inactive_history_style
                     ),
diff --git a/test/orm/test_relationships.py b/test/orm/test_relationships.py
index fd4230e150..8d27742c33 100644
--- a/test/orm/test_relationships.py
+++ b/test/orm/test_relationships.py
@@ -2589,6 +2589,55 @@ class JoinConditionErrorTest(fixtures.TestBase):
         registry.map_imperatively(C2, t3)
         assert C1.c2.property.primaryjoin.compare(t1.c.id == t3.c.t1id)
 
+    @testing.combinations(
+        "annotation", "local_remote", argnames="remote_anno_type"
+    )
+    @testing.combinations("orm_col", "core_col", argnames="use_col_from")
+    def test_no_remote_on_local_only_cols(
+        self, decl_base, remote_anno_type, use_col_from
+    ):
+        """test #7094.
+
+        a warning should be emitted for an inappropriate remote_side argument
+
+        """
+
+        class A(decl_base):
+            __tablename__ = "a"
+
+            id = Column(Integer, primary_key=True)
+            data = Column(String)
+
+            if remote_anno_type == "annotation":
+                if use_col_from == "core_col":
+                    bs = relationship(
+                        "B",
+                        primaryjoin=lambda: remote(A.__table__.c.id)
+                        == B.__table__.c.a_id,
+                    )
+                elif use_col_from == "orm_col":
+                    bs = relationship(
+                        "B", primaryjoin="remote(A.id) == B.a_id"
+                    )
+            elif remote_anno_type == "local_remote":
+                if use_col_from == "core_col":
+                    bs = relationship(
+                        "B", remote_side=lambda: A.__table__.c.id
+                    )
+                elif use_col_from == "orm_col":
+                    bs = relationship("B", remote_side="A.id")
+
+        class B(decl_base):
+            __tablename__ = "b"
+            id = Column(Integer, primary_key=True)
+            a_id = Column(ForeignKey("a.id"))
+
+        with expect_warnings(
+            r"Expression a.id is marked as 'remote', but these column\(s\) "
+            r"are local to the local side. "
+        ):
+            decl_base.registry.configure()
+
     def test_join_error_raised(self, registry):
         m = MetaData()
         t1 = Table("t1", m, Column("id", Integer, primary_key=True))