Support filter_by() from columns, functions, Core SQL

Fixed regression where :meth:`_orm.Query.filter_by` would not work if the
lead entity were a SQL function or other expression derived from the
primary entity in question, rather than a simple entity or column of that
entity. Additionally, improved the behavior of
:meth:`_sql.Select.filter_by` overall to work with column expressions even
in a non-ORM context.

Fixes: #6414
Change-Id: I316b5bf98293bec1ede08787f6181dd14be85419

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index e27b97802..416a4e82e 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -300,6 +300,13 @@ class ClauseElement(
             f = f._is_clone_of
         return s
 
+    @property
+    def entity_namespace(self):
+        raise AttributeError(
+            "This SQL expression has no entity namespace "
+            "with which to filter from."
+        )
+
     def __getstate__(self):
         d = self.__dict__.copy()
         d.pop("_is_clone_of", None)
@@ -4664,6 +4671,13 @@ class ColumnClause(
         # expect the columns of tables and subqueries to be leaf nodes.
         return []
 
+    @property
+    def entity_namespace(self):
+        if self.table is not None:
+            return self.table.entity_namespace
+        else:
+            return super(ColumnClause, self).entity_namespace
+
     @HasMemoized.memoized_attribute
     def _from_objects(self):
         t = self.table