Avoid deprecation warning in add/drop constraint

Ensure that alembic is compatible with the changes added in
sqlalchemy/sqlalchemy#13006
by explicitly setting isolate_from_table=True in sqlalchemy 2.1

Change-Id: I0dd3b2aa2932ca11fbde113fe4d92306fb1f2bbb

Author: CaselIT

alembic/ddl/impl.py

@@ -399,11 +399,15 @@ def drop_column(
             )
         )
 
-    def add_constraint(self, const: Any) -> None:
+    def add_constraint(self, const: Any, **kw: Any) -> None:
         if const._create_rule is None or const._create_rule(self):
-            self._exec(schema.AddConstraint(const))
+            if sqla_compat.sqla_2_1:
+                kw.setdefault("isolate_from_table", True)
+            self._exec(schema.AddConstraint(const, **kw))
 
     def drop_constraint(self, const: Constraint, **kw: Any) -> None:
+        if sqla_compat.sqla_2_1:
+            kw.setdefault("isolate_from_table", True)
         self._exec(schema.DropConstraint(const, **kw))
 
     def rename_table(

alembic/ddl/sqlite.py

@@ -74,7 +74,7 @@ def requires_recreate_in_batch(
         else:
             return False
 
-    def add_constraint(self, const: Constraint):
+    def add_constraint(self, const: Constraint, **kw: Any):
         # attempt to distinguish between an
         # auto-gen constraint and an explicit one
         if const._create_rule is None:

docs/build/unreleased/constraint_deprecation.rst

@@ -0,0 +1,8 @@
+.. change::
+    :tags: usecase
+
+    Avoid deprecation warning in add/drop constraint added in SQLAlchemy 2.1.
+    Ensure that alembic is compatible with the changes added in
+    https://github.com/sqlalchemy/sqlalchemy/issues/13006
+    by explicitly setting ``isolate_from_table=True`` when running with
+    SQLAlchemy 2.1 or greater.