fix(bug): database migration does not rollback schema version on hook failure (#5908)

* add tests

* correct expect schema version

* use conventional named return

* add rollback test and more description in godoc

* refactor to use commit at the end and defer rollback

* add comment

* lint

internal/db/schema/internal/postgres/postgres.go

@@ -202,7 +202,7 @@ func (p *Postgres) CommitRun(ctx context.Context) error {
 	return nil
 }
 
-// RollbackRun rolls back a transaction.
+// RollbackRun rolls back a transaction. If no transaction is active, it will return nil.
 func (p *Postgres) RollbackRun(ctx context.Context) error {
 	const op = "postgres.(Postgres).RollbackRun"
 	defer func() {

internal/db/schema/internal/postgres/postgres_test.go

@@ -46,6 +46,38 @@ create table foo (
 	assert.Equal(t, v, 1001)
 }
 
+func TestRun_Rollback(t *testing.T) {
+	ctx := context.Background()
+	p, _, _ := setup(ctx, t)
+
+	statements := bytes.NewReader([]byte(`
+create table foo (
+  id bigint primary key,
+  bar text
+);
+`))
+
+	err := p.StartRun(ctx)
+	require.NoError(t, err)
+
+	err = p.EnsureVersionTable(ctx)
+	require.NoError(t, err)
+
+	err = p.EnsureMigrationLogTable(ctx)
+	require.NoError(t, err)
+
+	err = p.Run(ctx, statements, 1001, "oss")
+	require.NoError(t, err)
+
+	err = p.RollbackRun(ctx)
+	require.NoError(t, err)
+
+	v, i, err := p.CurrentState(ctx, "oss")
+	require.NoError(t, err)
+	assert.False(t, i)
+	assert.Equal(t, -1, v)
+}
+
 func TestRun_NoTxn(t *testing.T) {
 	ctx := context.Background()
 	p, _, _ := setup(ctx, t)