chmigrate: add MissingMigrations

ch/db_test.go

@@ -294,6 +294,25 @@ func TestDateTime64(t *testing.T) {
 	require.Equal(t, in.Time.UnixNano(), out.Time.UnixNano())
 }
 
+func TestInvalidType(t *testing.T) {
+	t.Skip()
+
+	ctx := context.Background()
+
+	db := chDB()
+	defer db.Close()
+
+	var dest struct {
+		Numbers []float32
+	}
+	err := db.NewSelect().
+		ColumnExpr("groupArray(number) AS numbers").
+		TableExpr("numbers(10)").
+		Scan(ctx, &dest)
+	require.NoError(t, err)
+	require.Equal(t, []float64{}, dest.Numbers)
+}
+
 type Event struct {
 	ch.CHModel `ch:"goch_events,partition:toYYYYMM(created_at)"`
 

chmigrate/migrator.go

@@ -82,7 +82,7 @@ func (m *Migrator) MigrationsWithStatus(ctx context.Context) (MigrationSlice, er
 func (m *Migrator) migrationsWithStatus(ctx context.Context) (MigrationSlice, int64, error) {
 	sorted := m.migrations.Sorted()
 
-	applied, err := m.selectAppliedMigrations(ctx)
+	applied, err := m.AppliedMigrations(ctx)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -377,8 +377,31 @@ func (m *Migrator) MarkUnapplied(ctx context.Context, migration *Migration) erro
 	return err
 }
 
-// selectAppliedMigrations selects applied (applied) migrations in descending order.
-func (m *Migrator) selectAppliedMigrations(ctx context.Context) (MigrationSlice, error) {
+func (m *Migrator) TruncateTable(ctx context.Context) error {
+	_, err := m.db.Exec("TRUNCATE TABLE ?", ch.Ident(m.table))
+	return err
+}
+
+// MissingMigrations returns applied migrations that can no longer be found.
+func (m *Migrator) MissingMigrations(ctx context.Context) (MigrationSlice, error) {
+	applied, err := m.AppliedMigrations(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	existing := migrationMap(m.migrations.ms)
+	for i := len(applied) - 1; i >= 0; i-- {
+		m := &applied[i]
+		if _, ok := existing[m.Name]; ok {
+			applied = append(applied[:i], applied[i+1:]...)
+		}
+	}
+
+	return applied, nil
+}
+
+// AppliedMigrations selects applied migrations in descending order.
+func (m *Migrator) AppliedMigrations(ctx context.Context) (MigrationSlice, error) {
 	var ms MigrationSlice
 	if err := m.db.NewSelect().
 		ColumnExpr("*").