diff -U3 /tmp/cirrus-ci-build/src/test/regress/expected/generated_virtual.out /tmp/cirrus-ci-build/src/bin/pg_upgrade/tmp_check/results/generated_virtual.out
--- /tmp/cirrus-ci-build/src/test/regress/expected/generated_virtual.out	2025-09-12 12:57:59.028118336 +0000
+++ /tmp/cirrus-ci-build/src/bin/pg_upgrade/tmp_check/results/generated_virtual.out	2025-09-12 13:05:48.993022110 +0000
@@ -768,7 +768,7 @@
 ALTER INDEX gtestparted_a_idx ATTACH PARTITION gtestpart2_a_idx; --ok
 ALTER INDEX gtestparted_a_idx ATTACH PARTITION gtestpart2_a_idx_copy; --error
 ERROR:  cannot attach index "gtestpart2_a_idx_copy" as a partition of index "gtestparted_a_idx"
-DETAIL:  Another index is already attached for partition "gtestpart2".
+DETAIL:  Another index "gtestpart2_a_idx" is already attached for partition "gtestpart2".
 CREATE INDEX gtestparted_a_idx_1 on gtestparted(a);
 --now index gtestpart2_a_idx_copy should attach to the partition tree.
 SELECT * FROM pg_partition_tree('gtestparted_a_idx_1'::regclass);