check all directives in batch block until recreate selected

Fixed regression in batch mode due to 🎫`883` where the "auto" mode
of batch would fail to accommodate any additional migration directives
beyond encountering an ``add_column()`` directive, due to a mis-application
of the conditional logic that was added as part of this change, leading to
"recreate" mode not being used in cases where it is required for SQLite
such as for unique constraints.

Change-Id: I6315569caff5f3b33d152974ebecc8b18d9cc523
Fixes: #896

alembic/ddl/sqlite.py

@@ -56,7 +56,6 @@ def requires_recreate_in_batch(
                     and col.server_default.persisted
                 ):
                     return True
-                return False
             elif op[0] not in ("create_index", "drop_index"):
                 return True
         else:

docs/build/unreleased/896.rst

@@ -0,0 +1,10 @@
+.. change::
+    :tags: bug, regression, batch
+    :tickets: 896
+
+    Fixed regression in batch mode due to :ticket:`883` where the "auto" mode
+    of batch would fail to accommodate any additional migration directives
+    beyond encountering an ``add_column()`` directive, due to a mis-application
+    of the conditional logic that was added as part of this change, leading to
+    "recreate" mode not being used in cases where it is required for SQLite
+    such as for unique constraints.

tests/test_batch.py

@@ -1661,19 +1661,21 @@ def test_drop_pk_col_readd_col_also_pk_const(self):
         pk_const = inspect(self.conn).get_pk_constraint("foo")
         eq_(pk_const["constrained_columns"], ["id"])
 
-    def test_add_pk_constraint(self):
+    @testing.combinations(("always",), ("auto",), argnames="recreate")
+    def test_add_pk_constraint(self, recreate):
         self._no_pk_fixture()
-        with self.op.batch_alter_table("nopk", recreate="always") as batch_op:
+        with self.op.batch_alter_table("nopk", recreate=recreate) as batch_op:
             batch_op.create_primary_key("newpk", ["a", "b"])
 
         pk_const = inspect(self.conn).get_pk_constraint("nopk")
         with config.requirements.reflects_pk_names.fail_if():
             eq_(pk_const["name"], "newpk")
         eq_(pk_const["constrained_columns"], ["a", "b"])
 
+    @testing.combinations(("always",), ("auto",), argnames="recreate")
     @config.requirements.check_constraint_reflection
-    def test_add_ck_constraint(self):
-        with self.op.batch_alter_table("foo", recreate="always") as batch_op:
+    def test_add_ck_constraint(self, recreate):
+        with self.op.batch_alter_table("foo", recreate=recreate) as batch_op:
             batch_op.create_check_constraint("newck", text("x > 0"))
 
         ck_consts = inspect(self.conn).get_check_constraints("foo")
@@ -1682,12 +1684,13 @@ def test_add_ck_constraint(self):
         )
         eq_(ck_consts, [{"sqltext": "x > 0", "name": "newck"}])
 
+    @testing.combinations(("always",), ("auto",), argnames="recreate")
     @config.requirements.check_constraint_reflection
-    def test_drop_ck_constraint(self):
+    def test_drop_ck_constraint(self, recreate):
         self._ck_constraint_fixture()
 
         with self.op.batch_alter_table(
-            "ck_table", recreate="always"
+            "ck_table", recreate=recreate
         ) as batch_op:
             batch_op.drop_constraint("ck", "check")
 
@@ -1736,6 +1739,36 @@ def _assert_table_comment(self, tname, comment):
         tcomment = insp.get_table_comment(tname)
         eq_(tcomment, {"text": comment})
 
+    @testing.combinations(("always",), ("auto",), argnames="recreate")
+    def test_add_uq(self, recreate):
+        with self.op.batch_alter_table("foo", recreate=recreate) as batch_op:
+            batch_op.create_unique_constraint("newuk", ["x"])
+
+        uq_consts = inspect(self.conn).get_unique_constraints("foo")
+        eq_(
+            [
+                {"name": uc["name"], "column_names": uc["column_names"]}
+                for uc in uq_consts
+            ],
+            [{"name": "newuk", "column_names": ["x"]}],
+        )
+
+    @testing.combinations(("always",), ("auto",), argnames="recreate")
+    def test_add_uq_plus_col(self, recreate):
+        with self.op.batch_alter_table("foo", recreate=recreate) as batch_op:
+            batch_op.add_column(Column("y", Integer))
+            batch_op.create_unique_constraint("newuk", ["x", "y"])
+
+        uq_consts = inspect(self.conn).get_unique_constraints("foo")
+
+        eq_(
+            [
+                {"name": uc["name"], "column_names": uc["column_names"]}
+                for uc in uq_consts
+            ],
+            [{"name": "newuk", "column_names": ["x", "y"]}],
+        )
+
     @config.requirements.comments
     def test_add_table_comment(self):
         with self.op.batch_alter_table("foo") as batch_op: