fix: restore ALTER INDEX ... ATTACH PARTITION with indices and constraints

pkg/snapshot/generator/postgres/schema/pgdumprestore/snapshot_pg_dump_restore_generator.go

@@ -833,6 +833,13 @@ func (s *SnapshotGenerator) parseDump(d []byte) *dump {
 		case strings.HasPrefix(line, "ALTER TABLE") && isClusterOnAlterTable(line):
 			indicesAndConstraints.WriteString(line)
 			indicesAndConstraints.WriteString("\n\n")
+		case isAttachPartitionIndexStatement(line):
+			// ATTACH PARTITION references the parent index, which is created in
+			// the indices and constraints section. Restored in place it runs
+			// before that index exists, fails with "relation does not exist",
+			// and is never retried, leaving the parent index invalid.
+			indicesAndConstraints.WriteString(line)
+			indicesAndConstraints.WriteString("\n\n")
 		case strings.HasPrefix(line, "ALTER TABLE") && strings.Contains(line, "REPLICA IDENTITY"):
 			// REPLICA IDENTITY lines should be in the indicesAndConstraints section
 			// since they reference constraints/indices that are also there
@@ -1024,6 +1031,14 @@ func isIndexStatement(line string) bool {
 		strings.HasPrefix(line, "CREATE UNIQUE INDEX")
 }
 
+// isAttachPartitionIndexStatement reports whether the line attaches a partition
+// index to its parent. pg_dump emits these for partitioned tables, after the
+// CREATE INDEX statements they depend on.
+func isAttachPartitionIndexStatement(line string) bool {
+	return strings.HasPrefix(line, "ALTER INDEX") &&
+		strings.Contains(line, "ATTACH PARTITION")
+}
+
 func materializedViewName(line string) (string, bool) {
 	if !strings.HasPrefix(line, "CREATE MATERIALIZED VIEW ") {
 		return "", false

pkg/snapshot/generator/postgres/schema/pgdumprestore/snapshot_pg_dump_restore_generator_test.go

@@ -1764,6 +1764,44 @@ ALTER TABLE public.example_table CLUSTER ON example_table_created_at_idx;
 		strings.Index(string(dump.indicesAndConstraints), "CLUSTER ON example_table_created_at_idx"))
 }
 
+func TestSnapshotGenerator_parseDumpMovesAttachPartitionToConstraints(t *testing.T) {
+	t.Parallel()
+
+	dumpBytes := []byte(`CREATE TABLE public.events (
+    event_id bigint NOT NULL,
+    partition_id integer NOT NULL
+)
+PARTITION BY LIST (partition_id);
+
+CREATE TABLE public.events_0 (
+    event_id bigint NOT NULL,
+    partition_id integer NOT NULL
+);
+
+ALTER TABLE ONLY public.events ATTACH PARTITION public.events_0 FOR VALUES IN (0);
+
+CREATE INDEX events_partition_id_idx ON ONLY public.events USING btree (partition_id);
+
+CREATE INDEX events_0_partition_id_idx ON public.events_0 USING btree (partition_id);
+
+ALTER INDEX public.events_partition_id_idx ATTACH PARTITION public.events_0_partition_id_idx;
+`)
+
+	dump := (&SnapshotGenerator{}).parseDump(dumpBytes)
+
+	// the table attachment stays with the tables, the index attachment does not
+	require.Contains(t, string(dump.filtered), "ALTER TABLE ONLY public.events ATTACH PARTITION public.events_0")
+	require.NotContains(t, string(dump.filtered), "ALTER INDEX public.events_partition_id_idx ATTACH PARTITION")
+
+	require.Contains(t, string(dump.indicesAndConstraints), "ALTER INDEX public.events_partition_id_idx ATTACH PARTITION public.events_0_partition_id_idx;")
+
+	// and it has to land after the parent index it references, or it fails the
+	// same way it did when it was restored in place
+	require.Less(t,
+		strings.Index(string(dump.indicesAndConstraints), "CREATE INDEX events_partition_id_idx"),
+		strings.Index(string(dump.indicesAndConstraints), "ALTER INDEX public.events_partition_id_idx ATTACH PARTITION"))
+}
+
 func TestSnapshotGenerator_parseDumpMovesMaterializedViewIndexesToViews(t *testing.T) {
 	t.Parallel()