Fix new assertion for MERGE view_name ... DO NOTHING.

Such queries don't expand automatically updatable views, and ModifyTable
uses the wholerow attribute unconditionally.  The user-visible behavior
is fine, so change to more-specific assertions.  Commit
d5f788b41dc2cbdde6e7694c70dda54d829a5ed5 added the wrong assertion.
Back-patch to v17, where commit 5f2e179bd31e5f5803005101eb12a8d7bf8db8f3
introduced MERGE view_name.

Reported by Alexander Lakhin.

Discussion: https://postgr.es/m/e4b40a88-c134-6926-3196-bc4501cb87a2@gmail.com

2 files changed, 10 insertions, 0 deletions

diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index 9c21b768002..44aba0d1dcb 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -199,6 +199,9 @@ MERGE INTO ro_view13 AS t USING (VALUES (3, 'Row 3')) AS v(a,b) ON t.a = v.a
 ERROR:  cannot insert into view "ro_view13"
 DETAIL:  Views that do not select from a single table or view are not automatically updatable.
 HINT:  To enable inserting into the view using MERGE, provide an INSTEAD OF INSERT trigger.
+MERGE INTO ro_view13 AS t USING (VALUES (2, 'Row 2')) AS v(a,b) ON t.a = v.a
+  WHEN MATCHED THEN DO NOTHING
+  WHEN NOT MATCHED THEN DO NOTHING; -- should be OK to do nothing
 MERGE INTO ro_view13 AS t USING (VALUES (3, 'Row 3')) AS v(a,b) ON t.a = v.a
   WHEN MATCHED THEN DO NOTHING
   WHEN NOT MATCHED THEN DO NOTHING; -- should be OK to do nothing
@@ -375,6 +378,8 @@ DELETE FROM ro_view18;
 ERROR:  cannot delete from view "ro_view18"
 DETAIL:  Views that do not select from a single table or view are not automatically updatable.
 HINT:  To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.
+MERGE INTO ro_view18 AS t USING (VALUES (1, 'Row 1')) AS v(a,b) ON t.a = v.a
+  WHEN MATCHED THEN DO NOTHING; -- should be OK to do nothing
 UPDATE ro_view19 SET last_value=1000;
 ERROR:  cannot update view "ro_view19"
 DETAIL:  Views that do not select from a single table or view are not automatically updatable.
diff --git a/src/test/regress/sql/updatable_views.sql b/src/test/regress/sql/updatable_views.sql
index e0ab923d5d1..abfa5574a6e 100644
--- a/src/test/regress/sql/updatable_views.sql
+++ b/src/test/regress/sql/updatable_views.sql
@@ -68,6 +68,9 @@ MERGE INTO ro_view13 AS t USING (VALUES (2, 'Row 2')) AS v(a,b) ON t.a = v.a
   WHEN MATCHED THEN UPDATE SET b = v.b;
 MERGE INTO ro_view13 AS t USING (VALUES (3, 'Row 3')) AS v(a,b) ON t.a = v.a
   WHEN NOT MATCHED THEN INSERT VALUES (v.a, v.b);
+MERGE INTO ro_view13 AS t USING (VALUES (2, 'Row 2')) AS v(a,b) ON t.a = v.a
+  WHEN MATCHED THEN DO NOTHING
+  WHEN NOT MATCHED THEN DO NOTHING; -- should be OK to do nothing
 MERGE INTO ro_view13 AS t USING (VALUES (3, 'Row 3')) AS v(a,b) ON t.a = v.a
   WHEN MATCHED THEN DO NOTHING
   WHEN NOT MATCHED THEN DO NOTHING; -- should be OK to do nothing
@@ -121,6 +124,8 @@ DELETE FROM rw_view16 WHERE a=-3; -- should be OK
 -- Read-only views
 INSERT INTO ro_view17 VALUES (3, 'ROW 3');
 DELETE FROM ro_view18;
+MERGE INTO ro_view18 AS t USING (VALUES (1, 'Row 1')) AS v(a,b) ON t.a = v.a
+  WHEN MATCHED THEN DO NOTHING; -- should be OK to do nothing
 UPDATE ro_view19 SET last_value=1000;
 UPDATE ro_view20 SET b=upper(b);