Fix order of operations in CREATE OR REPLACE VIEW.

When CREATE OR REPLACE VIEW acts on an existing view, don't update the
view options until after the view query has been updated.

This is necessary in the case where CREATE OR REPLACE VIEW is used on
an existing view that is not updatable, and the new view is updatable
and specifies the WITH CHECK OPTION. In this case, attempting to apply
the new options to the view before updating its query fails, because
the options are applied using the ALTER TABLE infrastructure which
checks that WITH CHECK OPTION is only applied to an updatable view.

If new columns are being added to the view, that is also done using
the ALTER TABLE infrastructure, but it is important that that still be
done before updating the view query, because the rules system checks
that the query columns match those on the view relation. Added a
comment to explain that, in case someone is tempted to move that to
where the view options are now being set.

Back-patch to 9.4 where WITH CHECK OPTION was added.

Report: https://postgr.es/m/CAEZATCUp%3Dz%3Ds4SzZjr14bfct_bdJNwMPi-gFi3Xc5k1ntbsAgQ%40mail.gmail.com

2 files changed, 27 insertions, 0 deletions

diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index 8201d77a561..6fba613f0f5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -2452,3 +2452,16 @@ DROP VIEW v2;
 DROP VIEW v1;
 DROP TABLE t2;
 DROP TABLE t1;
+--
+-- Test CREATE OR REPLACE VIEW turning a non-updatable view into an
+-- auto-updatable view and adding check options in a single step
+--
+CREATE TABLE t1 (a int, b text);
+CREATE VIEW v1 AS SELECT null::int AS a;
+CREATE OR REPLACE VIEW v1 AS SELECT * FROM t1 WHERE a > 0 WITH CHECK OPTION;
+INSERT INTO v1 VALUES (1, 'ok'); -- ok
+INSERT INTO v1 VALUES (-1, 'invalid'); -- should fail
+ERROR:  new row violates check option for view "v1"
+DETAIL:  Failing row contains (-1, invalid).
+DROP VIEW v1;
+DROP TABLE t1;
diff --git a/src/test/regress/sql/updatable_views.sql b/src/test/regress/sql/updatable_views.sql
index f0084795416..bb9a3a61746 100644
--- a/src/test/regress/sql/updatable_views.sql
+++ b/src/test/regress/sql/updatable_views.sql
@@ -1098,3 +1098,17 @@ DROP VIEW v2;
 DROP VIEW v1;
 DROP TABLE t2;
 DROP TABLE t1;
+
+--
+-- Test CREATE OR REPLACE VIEW turning a non-updatable view into an
+-- auto-updatable view and adding check options in a single step
+--
+CREATE TABLE t1 (a int, b text);
+CREATE VIEW v1 AS SELECT null::int AS a;
+CREATE OR REPLACE VIEW v1 AS SELECT * FROM t1 WHERE a > 0 WITH CHECK OPTION;
+
+INSERT INTO v1 VALUES (1, 'ok'); -- ok
+INSERT INTO v1 VALUES (-1, 'invalid'); -- should fail
+
+DROP VIEW v1;
+DROP TABLE t1;