dialect/sql/schema: allow planning with indentation (#3363)

dialect/sql/schema/atlas.go

@@ -33,11 +33,12 @@ type Atlas struct {
 	withFixture bool // deprecated: with fks rename fixture
 	sum         bool // deprecated: sum file generation will be required
 
-	errNoPlan       bool // no plan error enabled
-	universalID     bool // global unique ids
-	dropColumns     bool // drop deleted columns
-	dropIndexes     bool // drop deleted indexes
-	withForeignKeys bool // with foreign keys
+	indent          string // plan indentation
+	errNoPlan       bool   // no plan error enabled
+	universalID     bool   // global unique ids
+	dropColumns     bool   // drop deleted columns
+	dropIndexes     bool   // drop deleted indexes
+	withForeignKeys bool   // with foreign keys
 	mode            Mode
 	hooks           []Hook            // hooks to apply before creation
 	diffHooks       []DiffHook        // diff hooks to run when diffing current and desired
@@ -804,6 +805,11 @@ func (a *Atlas) diff(ctx context.Context, name string, current, desired *schema.
 			filtered = append(filtered, c)
 		}
 	}
+	if a.indent != "" {
+		opts = append(opts, func(opts *migrate.PlanOptions) {
+			opts.Indent = a.indent
+		})
+	}
 	plan, err := a.atDriver.PlanChanges(ctx, name, filtered, opts...)
 	if err != nil {
 		return nil, err

dialect/sql/schema/migrate.go

@@ -41,6 +41,14 @@ func WithGlobalUniqueID(b bool) MigrateOption {
 	}
 }
 
+// WithIndent sets Atlas to generate SQL statements with indentation.
+// An empty string indicates no indentation.
+func WithIndent(indent string) MigrateOption {
+	return func(a *Atlas) {
+		a.indent = indent
+	}
+}
+
 // WithErrNoPlan sets Atlas to returns a migrate.ErrNoPlan in case
 // the migration plan is empty. Defaults to false.
 func WithErrNoPlan(b bool) MigrateOption {

dialect/sql/schema/migrate_test.go

@@ -292,13 +292,16 @@ func TestMigrate_Diff(t *testing.T) {
 	}, "\n")
 	requireFileEqual(t, filepath.Join(p, "changes.sql"), changesSQL)
 
+	// Enable indentations.
+	m, err = NewMigrate(db, WithFormatter(f), WithDir(d), WithGlobalUniqueID(true), WithIndent("  "))
+	require.NoError(t, err)
 	// Adding another node will result in a new entry to the TypeTable (without actually creating it).
 	_, err = db.ExecContext(ctx, changesSQL, nil, nil)
 	require.NoError(t, err)
 	require.NoError(t, m.NamedDiff(ctx, "changes_2", petsTable))
 	requireFileEqual(t,
 		filepath.Join(p, "changes_2.sql"), strings.Join([]string{
-			"CREATE TABLE `pets` (`id` integer NOT NULL PRIMARY KEY AUTOINCREMENT);",
+			"CREATE TABLE `pets` (\n  `id` integer NOT NULL PRIMARY KEY AUTOINCREMENT\n);",
 			fmt.Sprintf("INSERT INTO sqlite_sequence (name, seq) VALUES (\"pets\", %d);", 2<<32),
 			"INSERT INTO `ent_types` (`type`) VALUES ('pets');", "",
 		}, "\n"))