fix(pgmq): override drop_queue to conditionally drop objects

We introduced a patch to override pgmq.drop_queue(TEXT) to conditionally
drop objects only if they are part of the extension in `ansible/ansible/files/postgresql_extension_custom_scripts/pgmq/after-create.sql`
. This script has been installed together with existing 1.4.4 extensions.

When the user tries to upgrade pgmq from 1.4.4 to 1.5.1, the upgrade
process will fail because the upgrade script doesn't expect
`pgmq.drop_queue(TEXT)` to be exist.

This change introduce the same patch present in `æfter-creat.Sql` in the
upgrade from 1.4.5 to 1.5.0 to make sure the upgrade process will keep
our custom behavior.

Author: jfroche

nix/ext/pgmq/0001-feat-override-pgmq.drop_queue-TEXT-to-conditionally-.patch

@@ -0,0 +1,94 @@
+From bffc70636d34584158cd40c969048cacfcc1661d Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jean-Fran=C3=A7ois=20Roche?= <[email protected]>
+Date: Thu, 9 Oct 2025 00:33:22 +0200
+Subject: [PATCH] feat: override pgmq.drop_queue(TEXT) to conditionally drop
+ objects only if they are part of the extension
+
+Override the pgmq.drop_queue to check if relevant tables are owned
+by the pgmq extension before attempting to run
+`alter extension pgmq drop table ...`
+this is necessary because, to enable nightly logical backups to include user queues
+we automatically detach them from pgmq.
+
+this update is backwards compatible with version 1.4.4 but should be removed once we're on
+physical backups everywhere
+---
+ pgmq-extension/sql/pgmq--1.4.5--1.5.0.sql | 55 ++++++++++++++++++++++-
+ 1 file changed, 54 insertions(+), 1 deletion(-)
+
+diff --git a/pgmq-extension/sql/pgmq--1.4.5--1.5.0.sql b/pgmq-extension/sql/pgmq--1.4.5--1.5.0.sql
+index 5754eed..3053a3d 100644
+--- a/pgmq-extension/sql/pgmq--1.4.5--1.5.0.sql
++++ b/pgmq-extension/sql/pgmq--1.4.5--1.5.0.sql
+@@ -122,7 +122,7 @@ BEGIN
+ END;
+ $$ LANGUAGE plpgsql;
+ 
+-CREATE FUNCTION pgmq.drop_queue(queue_name TEXT)
++CREATE OR REPLACE FUNCTION pgmq.drop_queue(queue_name TEXT)
+ RETURNS BOOLEAN AS $$
+ DECLARE
+     qtable TEXT := pgmq.format_table_name(queue_name, 'q');
+@@ -139,6 +139,59 @@ BEGIN
+         queue_name
+     ) INTO partitioned;
+ 
++    -- NEW CONDITIONAL CHECK
++    if exists (
++        select 1
++        from pg_class c
++        join pg_depend d on c.oid = d.objid
++        join pg_extension e on d.refobjid = e.oid
++        where c.relname = qtable and e.extname = 'pgmq'
++    ) then
++
++        EXECUTE FORMAT(
++            $QUERY$
++            ALTER EXTENSION pgmq DROP TABLE pgmq.%I
++            $QUERY$,
++            qtable
++        );
++
++    end if;
++
++    -- NEW CONDITIONAL CHECK
++    if exists (
++        select 1
++        from pg_class c
++        join pg_depend d on c.oid = d.objid
++        join pg_extension e on d.refobjid = e.oid
++        where c.relname = qtable_seq and e.extname = 'pgmq'
++    ) then
++        EXECUTE FORMAT(
++            $QUERY$
++            ALTER EXTENSION pgmq DROP SEQUENCE pgmq.%I
++            $QUERY$,
++            qtable_seq
++        );
++
++    end if;
++
++    -- NEW CONDITIONAL CHECK
++    if exists (
++        select 1
++        from pg_class c
++        join pg_depend d on c.oid = d.objid
++        join pg_extension e on d.refobjid = e.oid
++        where c.relname = atable and e.extname = 'pgmq'
++    ) then
++
++    EXECUTE FORMAT(
++        $QUERY$
++        ALTER EXTENSION pgmq DROP TABLE pgmq.%I
++        $QUERY$,
++        atable
++    );
++
++    end if;
++
+     EXECUTE FORMAT(
+         $QUERY$
+         ALTER EXTENSION pgmq DROP TABLE pgmq.%I
+-- 
+2.51.0
+

nix/ext/pgmq.nix renamed to nix/ext/pgmq/default.nix

@@ -9,7 +9,7 @@ let
   pname = "pgmq";
 
   # Load version configuration from external file
-  allVersions = (builtins.fromJSON (builtins.readFile ./versions.json)).${pname};
+  allVersions = (builtins.fromJSON (builtins.readFile ../versions.json)).${pname};
 
   # Filter versions compatible with current PostgreSQL version
   supportedVersions = lib.filterAttrs (
@@ -37,6 +37,10 @@ let
         inherit hash;
       };
 
+      patches = lib.optionals (version == "1.5.1") [
+        ./0001-feat-override-pgmq.drop_queue-TEXT-to-conditionally-.patch
+      ];
+
       buildPhase = ''
         cd pgmq-extension
       '';

nix/packages/postgres.nix

@@ -22,7 +22,7 @@
         ../ext/pgroonga.nix
         ../ext/index_advisor.nix
         ../ext/wal2json.nix
-        ../ext/pgmq.nix
+        ../ext/pgmq
         ../ext/pg_repack.nix
         ../ext/pg-safeupdate.nix
         ../ext/plpgsql-check.nix