ensure intermediary mappers emit subclass IN

Fixed issue in :func:`_orm.selectin_polymorhpic` loader option where the
SELECT emitted would only accommodate for the child-most class among the
result rows that were returned, leading intermediary-class attributes to be
unloaded if there were no concrete instances of that intermediary-class
present in the result.   This issue only presented itself for multi-level
inheritance hierarchies.

Fixes: #11327
Change-Id: Iec88cc517613d031221a1c035c4cfb46db0154be
(cherry picked from commit 37c598a41efd2609622b1ca6ee698dbe0ab5ac8b)

diff --git a/doc/build/changelog/unreleased_20/11327.rst b/doc/build/changelog/unreleased_20/11327.rst
new file mode 100644 (file)
index 0000000..f7169ad
--- /dev/null
+++ b/doc/build/changelog/unreleased_20/11327.rst
@@ -0,0 +1,10 @@
+.. change::
+    :tags: bug, orm
+    :tickets: 11327
+
+    Fixed issue in :func:`_orm.selectin_polymorhpic` loader option where the
+    SELECT emitted would only accommodate for the child-most class among the
+    result rows that were returned, leading intermediary-class attributes to be
+    unloaded if there were no concrete instances of that intermediary-class
+    present in the result.   This issue only presented itself for multi-level
+    inheritance hierarchies.

diff --git a/lib/sqlalchemy/orm/loading.py b/lib/sqlalchemy/orm/loading.py
index 4e2cb8250fc5e3da6c62bd75b6246ce11c904600..6176d72a67e78718797c529f8921f444f072694a 100644 (file)
--- a/lib/sqlalchemy/orm/loading.py
+++ b/lib/sqlalchemy/orm/loading.py
@@ -1010,21 +1010,38 @@ def _instance_processor(
             # loading does not apply
             assert only_load_props is None
 
-            callable_ = _load_subclass_via_in(
-                context,
-                path,
-                selectin_load_via,
-                _polymorphic_from,
-                option_entities,
-            )
-            PostLoad.callable_for_path(
-                context,
-                load_path,
-                selectin_load_via.mapper,
-                selectin_load_via,
-                callable_,
-                selectin_load_via,
-            )
+            if selectin_load_via.is_mapper:
+                _load_supers = []
+                _endmost_mapper = selectin_load_via
+                while (
+                    _endmost_mapper
+                    and _endmost_mapper is not _polymorphic_from
+                ):
+                    _load_supers.append(_endmost_mapper)
+                    _endmost_mapper = _endmost_mapper.inherits
+            else:
+                _load_supers = [selectin_load_via]
+
+            for _selectinload_entity in _load_supers:
+                if PostLoad.path_exists(
+                    context, load_path, _selectinload_entity
+                ):
+                    continue
+                callable_ = _load_subclass_via_in(
+                    context,
+                    path,
+                    _selectinload_entity,
+                    _polymorphic_from,
+                    option_entities,
+                )
+                PostLoad.callable_for_path(
+                    context,
+                    load_path,
+                    _selectinload_entity.mapper,
+                    _selectinload_entity,
+                    callable_,
+                    _selectinload_entity,
+                )
 
     post_load = PostLoad.for_context(context, load_path, only_load_props)
 

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 0caed0e2fd0ec6e697d8fd148935b924ce336658..3052710f8250a5ff336fef621b9b93ea05f71e8b 100644 (file)
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -3805,6 +3805,7 @@ class Mapper(
         this subclass as a SELECT with IN.
 
         """
+
         strategy_options = util.preloaded.orm_strategy_options
 
         assert self.inherits

diff --git a/test/orm/inheritance/test_poly_loading.py b/test/orm/inheritance/test_poly_loading.py
index df286f0d35c817d40f7a14f99404d99b17af2982..a768c32754af24f74efd1f369c87b8be4eeb21cf 100644 (file)
--- a/test/orm/inheritance/test_poly_loading.py
+++ b/test/orm/inheritance/test_poly_loading.py
@@ -735,6 +735,66 @@ class TestGeometries(GeometryFixtureBase):
         with self.assert_statement_count(testing.db, 0):
             eq_(result, [d(d_data="d1"), e(e_data="e1")])
 
+    @testing.variation("include_intermediary_row", [True, False])
+    def test_threelevel_load_only_3lev(self, include_intermediary_row):
+        """test issue #11327"""
+
+        self._fixture_from_geometry(
+            {
+                "a": {
+                    "subclasses": {
+                        "b": {"subclasses": {"c": {}}},
+                    }
+                }
+            }
+        )
+
+        a, b, c = self.classes("a", "b", "c")
+        sess = fixture_session()
+        sess.add(c(a_data="a1", b_data="b1", c_data="c1"))
+        if include_intermediary_row:
+            sess.add(b(a_data="a1", b_data="b1"))
+        sess.commit()
+
+        sess = fixture_session()
+
+        pks = []
+        c_pks = []
+        with self.sql_execution_asserter(testing.db) as asserter:
+
+            for obj in sess.scalars(
+                select(a)
+                .options(selectin_polymorphic(a, classes=[b, c]))
+                .order_by(a.id)
+            ):
+                assert "b_data" in obj.__dict__
+                if isinstance(obj, c):
+                    assert "c_data" in obj.__dict__
+                    c_pks.append(obj.id)
+                pks.append(obj.id)
+
+        asserter.assert_(
+            CompiledSQL(
+                "SELECT a.id, a.type, a.a_data FROM a ORDER BY a.id", {}
+            ),
+            AllOf(
+                CompiledSQL(
+                    "SELECT c.id AS c_id, b.id AS b_id, a.id AS a_id, "
+                    "a.type AS a_type, c.c_data AS c_c_data FROM a JOIN b "
+                    "ON a.id = b.id JOIN c ON b.id = c.id WHERE a.id IN "
+                    "(__[POSTCOMPILE_primary_keys]) ORDER BY a.id",
+                    [{"primary_keys": c_pks}],
+                ),
+                CompiledSQL(
+                    "SELECT b.id AS b_id, a.id AS a_id, a.type AS a_type, "
+                    "b.b_data AS b_b_data FROM a JOIN b ON a.id = b.id "
+                    "WHERE a.id IN (__[POSTCOMPILE_primary_keys]) "
+                    "ORDER BY a.id",
+                    [{"primary_keys": pks}],
+                ),
+            ),
+        )
+
     @testing.combinations((True,), (False,))
     def test_threelevel_selectin_to_inline_awkward_alias_options(
         self, use_aliased_class
@@ -752,7 +812,9 @@ class TestGeometries(GeometryFixtureBase):
 
         a, b, c, d, e = self.classes("a", "b", "c", "d", "e")
         sess = fixture_session()
-        sess.add_all([d(d_data="d1"), e(e_data="e1")])
+        sess.add_all(
+            [d(c_data="c1", d_data="d1"), e(c_data="c2", e_data="e1")]
+        )
         sess.commit()
 
         from sqlalchemy import select
@@ -840,6 +902,15 @@ class TestGeometries(GeometryFixtureBase):
                     {},
                 ),
                 AllOf(
+                    # note this query is added due to the fix made in
+                    # #11327
+                    CompiledSQL(
+                        "SELECT c.id AS c_id, a.id AS a_id, a.type AS a_type, "
+                        "c.c_data AS c_c_data FROM a JOIN c ON a.id = c.id "
+                        "WHERE a.id IN (__[POSTCOMPILE_primary_keys]) "
+                        "ORDER BY a.id",
+                        [{"primary_keys": [1, 2]}],
+                    ),
                     CompiledSQL(
                         "SELECT d.id AS d_id, c.id AS c_id, a.id AS a_id, "
                         "a.type AS a_type, d.d_data AS d_d_data FROM a "
@@ -860,7 +931,10 @@ class TestGeometries(GeometryFixtureBase):
             )
 
         with self.assert_statement_count(testing.db, 0):
-            eq_(result, [d(d_data="d1"), e(e_data="e1")])
+            eq_(
+                result,
+                [d(c_data="c1", d_data="d1"), e(c_data="c2", e_data="e1")],
+            )
 
     def test_partial_load_no_invoke_eagers(self):
         # test issue #4199