accommodate HasEntityNamespace in context.all_selected_columns

Fixed regression in hybrid_property where a hybrid against a SQL function
would generate an ``AttributeError`` when attempting to generate an entry
for the ``.c`` collection of a subquery in some cases; among other things
this would impact its use in cases like that of ``Query.count()``.

Fixes: #6401
Change-Id: Icc243c699e9a5c88448076c6427ec389eaa8b8ed

4 files changed, 38 insertions, 6 deletions

diff --git a/doc/build/changelog/unreleased_14/6401.rst b/doc/build/changelog/unreleased_14/6401.rst
new file mode 100644
index 000000000..046d6825b
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/6401.rst
@@ -0,0 +1,9 @@
+.. change::
+    :tags: orm, bug, regression
+    :tickets: 6401
+
+    Fixed regression in hybrid_property where a hybrid against a SQL function
+    would generate an ``AttributeError`` when attempting to generate an entry
+    for the ``.c`` collection of a subquery in some cases; among other things
+    this would impact its use in cases like that of ``Query.count()``.
+
diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index b8974196c..2f8c8f940 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -483,6 +483,7 @@ class InstrumentedAttribute(Mapped):
 HasEntityNamespace = util.namedtuple(
     "HasEntityNamespace", ["entity_namespace"]
 )
+HasEntityNamespace.is_mapper = HasEntityNamespace.is_aliased_class = False
 
 
 def create_proxied_attribute(descriptor):
diff --git a/lib/sqlalchemy/orm/context.py b/lib/sqlalchemy/orm/context.py
index 55b61b19e..aeba9ed80 100644
--- a/lib/sqlalchemy/orm/context.py
+++ b/lib/sqlalchemy/orm/context.py
@@ -802,12 +802,13 @@ class ORMSelectCompileState(ORMCompileState, SelectState):
                 element.is_selectable
                 and "entity_namespace" in element._annotations
             ):
-                for elem in _select_iterables(
-                    element._annotations[
-                        "entity_namespace"
-                    ]._all_column_expressions
-                ):
-                    yield elem
+                ens = element._annotations["entity_namespace"]
+                if not ens.is_mapper and not ens.is_aliased_class:
+                    for elem in _select_iterables([element]):
+                        yield elem
+                else:
+                    for elem in _select_iterables(ens._all_column_expressions):
+                        yield elem
             else:
                 for elem in _select_iterables([element]):
                     yield elem
diff --git a/test/ext/test_hybrid.py b/test/ext/test_hybrid.py
index ee991782e..9085ccc96 100644
--- a/test/ext/test_hybrid.py
+++ b/test/ext/test_hybrid.py
@@ -493,6 +493,21 @@ class PropertyMirrorTest(fixtures.TestBase, AssertsCompiledSQL):
         return A
 
     @testing.fixture
+    def _function_fixture(self):
+        Base = declarative_base()
+
+        class A(Base):
+            __tablename__ = "a"
+            id = Column(Integer, primary_key=True)
+            value = Column(Integer)
+
+            @hybrid.hybrid_property
+            def foo_value(self):
+                return func.foo(self.value)
+
+        return A
+
+    @testing.fixture
     def _name_mismatch_fixture(self):
         Base = declarative_base()
 
@@ -537,6 +552,12 @@ class PropertyMirrorTest(fixtures.TestBase, AssertsCompiledSQL):
             "FROM a AS a_1 JOIN b ON a_1.id = b.aid",
         )
 
+    def test_c_collection_func_element(self, _function_fixture):
+        A = _function_fixture
+
+        stmt = select(A.id, A.foo_value)
+        eq_(stmt.subquery().c.keys(), ["id", "foo_value"])
+
     def test_filter_by_mismatched_col(self, _name_mismatch_fixture):
         A, B = _name_mismatch_fixture
         self.assert_compile(