Ensure no dependencies to index before drop

(cherry picked from commit 11a9a3771f)

src/backend/columnar/sql/columnar--10.2-2--10.2-3.sql

@@ -10,6 +10,17 @@
 --
 -- To do that, drop stripe_first_row_number_idx and create a unique
 -- constraint with the same name to keep the code change at minimum.
+--
+-- If we have a pg_depend entry for this index, we can not drop it as
+-- the extension depends on it. Remove the pg_depend entry if it exists.
+DELETE FROM pg_depend
+WHERE classid = 'pg_am'::regclass::oid
+    AND objid IN (select oid from pg_am where amname = 'columnar')
+    AND objsubid = 0
+    AND refclassid = 'pg_class'::regclass::oid
+    AND refobjid = 'columnar.stripe_first_row_number_idx'::regclass::oid
+    AND refobjsubid = 0
+    AND deptype = 'n';
 DROP INDEX columnar.stripe_first_row_number_idx;
 ALTER TABLE columnar.stripe ADD CONSTRAINT stripe_first_row_number_idx
 UNIQUE (storage_id, first_row_number);

src/backend/columnar/sql/downgrades/columnar--10.2-1--10.1-1.sql

@@ -8,5 +8,16 @@ DROP FUNCTION citus_internal.upgrade_columnar_storage(regclass);
 DROP FUNCTION citus_internal.downgrade_columnar_storage(regclass);
 
 -- drop "first_row_number" column and the index defined on it
+--
+-- If we have a pg_depend entry for this index, we can not drop it as
+-- the extension depends on it. Remove the pg_depend entry if it exists.
+DELETE FROM pg_depend
+WHERE classid = 'pg_am'::regclass::oid
+    AND objid IN (select oid from pg_am where amname = 'columnar')
+    AND objsubid = 0
+    AND refclassid = 'pg_class'::regclass::oid
+    AND refobjid = 'columnar.stripe_first_row_number_idx'::regclass::oid
+    AND refobjsubid = 0
+    AND deptype = 'n';
 DROP INDEX columnar.stripe_first_row_number_idx;
 ALTER TABLE columnar.stripe DROP COLUMN first_row_number;

src/backend/columnar/sql/downgrades/columnar--10.2-3--10.2-2.sql

@@ -1,4 +1,14 @@
 -- columnar--10.2-3--10.2-2.sql
-
+--
+-- If we have a pg_depend entry for this index, we can not drop it as
+-- the extension depends on it. Remove the pg_depend entry if it exists.
+DELETE FROM pg_depend
+WHERE classid = 'pg_am'::regclass::oid
+    AND objid IN (select oid from pg_am where amname = 'columnar')
+    AND objsubid = 0
+    AND refclassid = 'pg_class'::regclass::oid
+    AND refobjid = 'columnar.stripe_first_row_number_idx'::regclass::oid
+    AND refobjsubid = 0
+    AND deptype = 'n';
 ALTER TABLE columnar.stripe DROP CONSTRAINT stripe_first_row_number_idx;
 CREATE INDEX stripe_first_row_number_idx ON columnar.stripe USING BTREE(storage_id, first_row_number);

src/test/regress/expected/multi_extension.out

@@ -918,11 +918,7 @@ SELECT * FROM multi_extension.print_extension_changes();
 -- There was a bug when downgrading to 10.2-2 from 10.2-4
 -- Test that we do not have any issues with this particular downgrade
 ALTER EXTENSION citus UPDATE TO '10.2-2';
-ERROR:  cannot drop constraint stripe_first_row_number_idx on table columnar.stripe because other objects depend on it
-DETAIL:  access method columnar depends on index columnar.stripe_first_row_number_idx
-HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER EXTENSION citus UPDATE TO '10.2-4';
-NOTICE:  version "10.2-4" of extension "citus" is already installed
 SELECT * FROM multi_extension.print_extension_changes();
  previous_object | current_object
 ---------------------------------------------------------------------