Only convert Range for sqlalchemy Range object

Refined the new approach to range objects described at :ref:`change_7156`
to accommodate driver-specific range and multirange objects, to better
accommodate both legacy code as well as when passing results from raw SQL
result sets back into new range or multirange expressions.

Fixes: #8690
Change-Id: I7e62c47067f695c6380ad0fe2fe19deaf33594d1

1 files changed, 3 insertions, 5 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index 350f4b616..4a8df5b5e 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -503,16 +503,14 @@ class _Psycopg2Range(ranges.AbstractRangeImpl):
     _psycopg2_range_cls = "none"
 
     def bind_processor(self, dialect):
-        Range = getattr(
+        psycopg2_Range = getattr(
             cast(PGDialect_psycopg2, dialect)._psycopg2_extras,
             self._psycopg2_range_cls,
         )
 
-        NoneType = type(None)
-
         def to_range(value):
-            if not isinstance(value, (str, NoneType)):
-                value = Range(
+            if isinstance(value, ranges.Range):
+                value = psycopg2_Range(
                     value.lower, value.upper, value.bounds, value.empty
                 )
             return value