Refactor gen_defaults to support multiple generated code blocks in the same...

Refactor gen_defaults to support multiple generated code blocks in the same file independently. (#107278)

dev/tools/gen_defaults/README.md

@@ -15,10 +15,10 @@ dart dev/tools/gen_defaults/bin/gen_defaults.dart
 There is a template file for every component that needs defaults from
 the token database. These templates are implemented as subclasses of
 `TokenTemplate`. This base class provides some utilities and a structure
-for adding a new chunk of generated code to the bottom of a given file.
+for adding a new block of generated code to the bottom of a given file.
 
 Templates need to override the `generate` method to provide the generated
-code chunk as a string. The tokens are represented as a `Map<String, dynamic>`
+code block as a string. The tokens are represented as a `Map<String, dynamic>`
 that is loaded from `data/material-tokens.json`. Templates can look up
 whatever properties are needed in this structure to provide the properties
 needed for the component.

dev/tools/gen_defaults/bin/gen_defaults.dart

@@ -99,20 +99,20 @@ Future<void> main(List<String> args) async {
   tokens['colorsLight'] = _readTokenFile('color_light.json');
   tokens['colorsDark'] = _readTokenFile('color_dark.json');
 
-  AppBarTemplate('$materialLib/app_bar.dart', tokens).updateFile();
-  ButtonTemplate('md.comp.elevated-button', '$materialLib/elevated_button.dart', tokens).updateFile();
-  ButtonTemplate('md.comp.outlined-button', '$materialLib/outlined_button.dart', tokens).updateFile();
-  ButtonTemplate('md.comp.text-button', '$materialLib/text_button.dart', tokens).updateFile();
-  CardTemplate('$materialLib/card.dart', tokens).updateFile();
-  ChipActionTemplate('$materialLib/chip_action.dart', tokens).updateFile();
-  ChipFilterTemplate('$materialLib/chip_filter.dart', tokens).updateFile();
-  ChipFilterTemplate('$materialLib/chip_choice.dart', tokens).updateFile();
-  ChipInputTemplate('$materialLib/chip_input.dart', tokens).updateFile();
-  DialogTemplate('$materialLib/dialog.dart', tokens).updateFile();
-  FABTemplate('$materialLib/floating_action_button.dart', tokens).updateFile();
-  IconButtonTemplate('$materialLib/icon_button.dart', tokens).updateFile();
-  NavigationBarTemplate('$materialLib/navigation_bar.dart', tokens).updateFile();
-  NavigationRailTemplate('$materialLib/navigation_rail.dart', tokens).updateFile();
-  SurfaceTintTemplate('$materialLib/elevation_overlay.dart', tokens).updateFile();
-  TypographyTemplate('$materialLib/typography.dart', tokens).updateFile();
+  AppBarTemplate('AppBar', '$materialLib/app_bar.dart', tokens).updateFile();
+  ButtonTemplate('md.comp.elevated-button', 'ElevatedButton', '$materialLib/elevated_button.dart', tokens).updateFile();
+  ButtonTemplate('md.comp.outlined-button', 'OutlinedButton', '$materialLib/outlined_button.dart', tokens).updateFile();
+  ButtonTemplate('md.comp.text-button', 'TextButton', '$materialLib/text_button.dart', tokens).updateFile();
+  CardTemplate('Card', '$materialLib/card.dart', tokens).updateFile();
+  ChipActionTemplate('ActionChip', '$materialLib/chip_action.dart', tokens).updateFile();
+  ChipFilterTemplate('FilterChip', '$materialLib/chip_filter.dart', tokens).updateFile();
+  ChipFilterTemplate('FilterChip', '$materialLib/chip_choice.dart', tokens).updateFile();
+  ChipInputTemplate('InputChip', '$materialLib/chip_input.dart', tokens).updateFile();
+  DialogTemplate('Dialog', '$materialLib/dialog.dart', tokens).updateFile();
+  FABTemplate('FAB', '$materialLib/floating_action_button.dart', tokens).updateFile();
+  IconButtonTemplate('IconButton', '$materialLib/icon_button.dart', tokens).updateFile();
+  NavigationBarTemplate('NavigationBar', '$materialLib/navigation_bar.dart', tokens).updateFile();
+  NavigationRailTemplate('NavigationRail', '$materialLib/navigation_rail.dart', tokens).updateFile();
+  SurfaceTintTemplate('SurfaceTint', '$materialLib/elevation_overlay.dart', tokens).updateFile();
+  TypographyTemplate('Typography', '$materialLib/typography.dart', tokens).updateFile();
 }

dev/tools/gen_defaults/lib/app_bar_template.dart

@@ -5,7 +5,7 @@
 import 'template.dart';
 
 class AppBarTemplate extends TokenTemplate {
-  const AppBarTemplate(super.fileName, super.tokens)
+  const AppBarTemplate(super.blockName, super.fileName, super.tokens)
     : super(
       colorSchemePrefix: '_colors.',
       textThemePrefix: '_textTheme.',
@@ -13,9 +13,8 @@ class AppBarTemplate extends TokenTemplate {
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends AppBarTheme {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends AppBarTheme {
+  _${blockName}DefaultsM3(this.context)
     : super(
       elevation: ${elevation('md.comp.top-app-bar.small.container')},
       scrolledUnderElevation: ${elevation('md.comp.top-app-bar.small.on-scroll.container')},

dev/tools/gen_defaults/lib/button_template.dart

@@ -5,10 +5,9 @@
 import 'template.dart';
 
 class ButtonTemplate extends TokenTemplate {
-  const ButtonTemplate(this.tokenGroup, String fileName, Map<String, dynamic> tokens)
-    : super(fileName, tokens,
-        colorSchemePrefix: '_colors.',
-      );
+  const ButtonTemplate(this.tokenGroup, super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+  });
 
   final String tokenGroup;
 
@@ -55,9 +54,8 @@ class ButtonTemplate extends TokenTemplate {
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends ButtonStyle {
+  _${blockName}DefaultsM3(this.context)
    : super(
        animationDuration: kThemeChangeDuration,
        enableFeedback: true,

dev/tools/gen_defaults/lib/card_template.dart

@@ -5,13 +5,13 @@
 import 'template.dart';
 
 class CardTemplate extends TokenTemplate {
-  const CardTemplate(super.fileName, super.tokens);
+  const CardTemplate(super.blockName, super.fileName, super.tokens);
 
   @override
   String generate() => '''
 // Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends CardTheme {
-  const _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends CardTheme {
+  const _${blockName}DefaultsM3(this.context)
     : super(
         clipBehavior: Clip.none,
         elevation: ${elevation("md.comp.elevated-card.container")},

dev/tools/gen_defaults/lib/chip_action_template.dart

@@ -6,16 +6,15 @@ import 'template.dart';
 
 class ChipActionTemplate extends TokenTemplate {
 
-  const ChipActionTemplate(super.fileName, super.tokens);
+  const ChipActionTemplate(super.blockName, super.fileName, super.tokens);
 
   static const String tokenGroup = 'md.comp.assist-chip';
   static const String variant = '.flat';
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled)
+class _${blockName}DefaultsM3 extends ChipThemeData {
+  const _${blockName}DefaultsM3(this.context, this.isEnabled)
     : super(
         elevation: ${elevation("$tokenGroup$variant.container")},
         shape: ${shape("$tokenGroup.container")},

dev/tools/gen_defaults/lib/chip_filter_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class ChipFilterTemplate extends TokenTemplate {
-  const ChipFilterTemplate(super.fileName, super.tokens);
+  const ChipFilterTemplate(super.blockName, super.fileName, super.tokens);
 
   static const String tokenGroup = 'md.comp.filter-chip';
   static const String variant = '.flat';
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled, this.isSelected)
+class _${blockName}DefaultsM3 extends ChipThemeData {
+  const _${blockName}DefaultsM3(this.context, this.isEnabled, this.isSelected)
     : super(
         elevation: ${elevation("$tokenGroup$variant.container")},
         shape: ${shape("$tokenGroup.container")},

dev/tools/gen_defaults/lib/chip_input_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class ChipInputTemplate extends TokenTemplate {
-  const ChipInputTemplate(super.fileName, super.tokens);
+  const ChipInputTemplate(super.blockName, super.fileName, super.tokens);
 
   static const String tokenGroup = 'md.comp.input-chip';
   static const String variant = '';
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled)
+class _${blockName}DefaultsM3 extends ChipThemeData {
+  const _${blockName}DefaultsM3(this.context, this.isEnabled)
     : super(
         elevation: ${elevation("$tokenGroup$variant.container")},
         shape: ${shape("$tokenGroup.container")},

dev/tools/gen_defaults/lib/dialog_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class DialogTemplate extends TokenTemplate {
-  const DialogTemplate(super.fileName, super.tokens)
-    : super(colorSchemePrefix: '_colors.',
-        textThemePrefix: '_textTheme.'
-      );
+  const DialogTemplate(super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+    super.textThemePrefix = '_textTheme.'
+  });
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends DialogTheme {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends DialogTheme {
+  _${blockName}DefaultsM3(this.context)
     : super(
         alignment: Alignment.center,
         elevation: ${elevation("md.comp.dialog.container")},

dev/tools/gen_defaults/lib/fab_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class FABTemplate extends TokenTemplate {
-  const FABTemplate(super.fileName, super.tokens)
-    : super(colorSchemePrefix: '_colors.',
-        textThemePrefix: '_textTheme.',
-      );
+  const FABTemplate(super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+    super.textThemePrefix = '_textTheme.',
+  });
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends FloatingActionButtonThemeData {
-  _TokenDefaultsM3(this.context, this.type, this.hasChild)
+class _${blockName}DefaultsM3 extends FloatingActionButtonThemeData {
+  _${blockName}DefaultsM3(this.context, this.type, this.hasChild)
     : super(
         elevation: ${elevation("md.comp.fab.primary.container")},
         focusElevation: ${elevation("md.comp.fab.primary.focus.container")},

dev/tools/gen_defaults/lib/icon_button_template.dart

@@ -5,15 +5,14 @@
 import 'template.dart';
 
 class IconButtonTemplate extends TokenTemplate {
-  const IconButtonTemplate(super.fileName, super.tokens)
-      : super(colorSchemePrefix: '_colors.',
-  );
+  const IconButtonTemplate(super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+  });
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends ButtonStyle {
+  _${blockName}DefaultsM3(this.context)
     : super(
         animationDuration: kThemeChangeDuration,
         enableFeedback: true,

dev/tools/gen_defaults/lib/navigation_bar_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class NavigationBarTemplate extends TokenTemplate {
-  const NavigationBarTemplate(super.fileName, super.tokens)
-    : super(colorSchemePrefix: '_colors.',
-        textThemePrefix: '_textTheme.',
-      );
+  const NavigationBarTemplate(super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+    super.textThemePrefix = '_textTheme.',
+  });
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends NavigationBarThemeData {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends NavigationBarThemeData {
+  _${blockName}DefaultsM3(this.context)
       : super(
           height: ${tokens["md.comp.navigation-bar.container.height"]},
           elevation: ${elevation("md.comp.navigation-bar.container")},

dev/tools/gen_defaults/lib/navigation_rail_template.dart

@@ -5,16 +5,15 @@
 import 'template.dart';
 
 class NavigationRailTemplate extends TokenTemplate {
-  const NavigationRailTemplate(super.fileName, super.tokens)
-    : super(colorSchemePrefix: '_colors.',
-        textThemePrefix: '_textTheme.',
-      );
+  const NavigationRailTemplate(super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+    super.textThemePrefix = '_textTheme.',
+  });
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-class _TokenDefaultsM3 extends NavigationRailThemeData {
-  _TokenDefaultsM3(this.context)
+class _${blockName}DefaultsM3 extends NavigationRailThemeData {
+  _${blockName}DefaultsM3(this.context)
       : super(
           elevation: ${elevation("md.comp.navigation-rail.container")},
           groupAlignment: -1,

dev/tools/gen_defaults/lib/surface_tint.dart

@@ -5,12 +5,10 @@
 import 'template.dart';
 
 class SurfaceTintTemplate extends TokenTemplate {
-  const SurfaceTintTemplate(super.fileName, super.tokens);
+  const SurfaceTintTemplate(super.blockName, super.fileName, super.tokens);
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
-
 // Surface tint opacities based on elevations according to the
 // Material Design 3 specification:
 //   https://m3.material.io/styles/color/the-color-system/color-roles

dev/tools/gen_defaults/lib/template.dart

@@ -5,50 +5,83 @@
 import 'dart:io';
 
 abstract class TokenTemplate {
-  const TokenTemplate(this.fileName, this.tokens, {
+  const TokenTemplate(this.blockName, this.fileName, this.tokens, {
     this.colorSchemePrefix = 'Theme.of(context).colorScheme.',
     this.textThemePrefix = 'Theme.of(context).textTheme.'
   });
 
+  /// Name of the code block that this template will generate.
+  ///
+  /// Used to identify an existing block when updating it.
+  final String blockName;
+
+  /// Name of the file that will be updated with the generated code.
+  final String fileName;
+
+  /// Map of token data extracted from the Material Design token database.
+  final Map<String, dynamic> tokens;
+
+  /// Optional prefix prepended to color definitions.
+  ///
+  /// Defaults to 'Theme.of(context).colorScheme.'
+  final String colorSchemePrefix;
+
+  /// Optional prefix prepended to text style definitians.
+  ///
+  /// Defaults to 'Theme.of(context).textTheme.'
+  final String textThemePrefix;
+
   static const String beginGeneratedComment = '''
 
-// BEGIN GENERATED TOKEN PROPERTIES
-''';
+// BEGIN GENERATED TOKEN PROPERTIES''';
 
   static const String headerComment = '''
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
 ''';
 
   static const String endGeneratedComment = '''
 
-// END GENERATED TOKEN PROPERTIES
-''';
-
-  final String fileName;
-  final Map<String, dynamic> tokens;
-  final String colorSchemePrefix;
-  final String textThemePrefix;
+// END GENERATED TOKEN PROPERTIES''';
 
   /// Replace or append the contents of the file with the text from [generate].
   ///
-  /// If the file already contains generated block at the end, it will
-  /// be replaced by the [generate] output. Otherwise the content will
-  /// just be appended to the end of the file.
+  /// If the file already contains a generated text block matching the
+  /// [blockName], it will be replaced by the [generate] output. Otherwise
+  /// the content will just be appended to the end of the file.
   Future<void> updateFile() async {
-    String contents = File(fileName).readAsStringSync();
-    final int previousGeneratedIndex = contents.indexOf(beginGeneratedComment);
-    if (previousGeneratedIndex != -1) {
-      contents = contents.substring(0, previousGeneratedIndex);
+    final String contents = File(fileName).readAsStringSync();
+    final String beginComment = '$beginGeneratedComment - $blockName\n';
+    final String endComment = '$endGeneratedComment - $blockName\n';
+    final int beginPreviousBlock = contents.indexOf(beginComment);
+    final int endPreviousBlock = contents.indexOf(endComment);
+    late String contentBeforeBlock;
+    late String contentAfterBlock;
+    if (beginPreviousBlock != -1) {
+      if (endPreviousBlock < beginPreviousBlock) {
+        print('Unable to find block named $blockName in $fileName, skipping code generation.');
+        return;
+      }
+      // Found a valid block matching the name, so record the content before and after.
+      contentBeforeBlock = contents.substring(0, beginPreviousBlock);
+      contentAfterBlock = contents.substring(endPreviousBlock + endComment.length);
+    } else {
+      // Just append to the bottom.
+      contentBeforeBlock = contents;
+      contentAfterBlock = '';
     }
-    final StringBuffer buffer = StringBuffer(contents);
-    buffer.write(beginGeneratedComment);
+
+    final StringBuffer buffer = StringBuffer(contentBeforeBlock);
+    buffer.write(beginComment);
     buffer.write(headerComment);
+    buffer.write('// Token database version: ${tokens['version']}\n\n');
     buffer.write(generate());
-    buffer.write(endGeneratedComment);
+    buffer.write(endComment);
+    buffer.write(contentAfterBlock);
     File(fileName).writeAsStringSync(buffer.toString());
   }
 

dev/tools/gen_defaults/lib/typography_template.dart

@@ -5,11 +5,10 @@
 import 'template.dart';
 
 class TypographyTemplate extends TokenTemplate {
-  const TypographyTemplate(super.fileName, super.tokens);
+  const TypographyTemplate(super.blockName, super.fileName, super.tokens);
 
   @override
   String generate() => '''
-// Generated version ${tokens["version"]}
 class _M3Typography {
   _M3Typography._();
 

dev/tools/gen_defaults/test/gen_defaults_test.dart

@@ -23,24 +23,27 @@ void main() {
 
       // Have a test template append new parameterized content to the end of
       // the file.
-      final Map<String, dynamic> tokens = <String, dynamic>{'foo': 'Foobar', 'bar': 'Barfoo'};
-      TestTemplate(tempFile.path, tokens).updateFile();
+      final Map<String, dynamic> tokens = <String, dynamic>{'version': '0.0', 'foo': 'Foobar', 'bar': 'Barfoo'};
+      TestTemplate('Test', tempFile.path, tokens).updateFile();
 
       expect(tempFile.readAsStringSync(), '''
 // This is a file with stuff in it.
 // This part shouldn't be changed by
 // the template.
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Test
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
 
 static final String tokenFoo = 'Foobar';
 static final String tokenBar = 'Barfoo';
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Test
 ''');
 
     } finally {
@@ -59,38 +62,166 @@ static final String tokenBar = 'Barfoo';
 // This part shouldn't be changed by
 // the template.
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Test
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Token database version: 0.0
 
 static final String tokenFoo = 'Foobar';
 static final String tokenBar = 'Barfoo';
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Test
 ''');
 
       // Have a test template append new parameterized content to the end of
       // the file.
-      final Map<String, dynamic> tokens = <String, dynamic>{'foo': 'foo', 'bar': 'bar'};
-      TestTemplate(tempFile.path, tokens).updateFile();
+      final Map<String, dynamic> tokens = <String, dynamic>{'version': '0.0', 'foo': 'foo', 'bar': 'bar'};
+      TestTemplate('Test', tempFile.path, tokens).updateFile();
+
+      expect(tempFile.readAsStringSync(), '''
+// This is a file with stuff in it.
+// This part shouldn't be changed by
+// the template.
+
+// BEGIN GENERATED TOKEN PROPERTIES - Test
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
+
+static final String tokenFoo = 'foo';
+static final String tokenBar = 'bar';
+
+// END GENERATED TOKEN PROPERTIES - Test
+''');
+
+    } finally {
+      tempDir.deleteSync(recursive: true);
+    }
+  });
+
+  test('Multiple templates can modify different code blocks in the same file', () {
+    final Directory tempDir = Directory.systemTemp.createTempSync('gen_defaults');
+    try {
+      // Create a temporary file with some content.
+      final File tempFile = File(path.join(tempDir.path, 'test_template.txt'));
+      tempFile.createSync();
+      tempFile.writeAsStringSync('''
+// This is a file with stuff in it.
+// This part shouldn't be changed by
+// the template.
+''');
+
+      // Update file with a template for 'Block 1'
+      {
+        final Map<String, dynamic> tokens = <String, dynamic>{'version': '0.0', 'foo': 'foo', 'bar': 'bar'};
+        TestTemplate('Block 1', tempFile.path, tokens).updateFile();
+      }
+      expect(tempFile.readAsStringSync(), '''
+// This is a file with stuff in it.
+// This part shouldn't be changed by
+// the template.
+
+// BEGIN GENERATED TOKEN PROPERTIES - Block 1
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
+
+static final String tokenFoo = 'foo';
+static final String tokenBar = 'bar';
 
+// END GENERATED TOKEN PROPERTIES - Block 1
+''');
+
+      // Update file with a template for 'Block 2', which should append but not
+      // disturb the code in 'Block 1'.
+      {
+        final Map<String, dynamic> tokens = <String, dynamic>{'version': '0.0', 'foo': 'bar', 'bar': 'foo'};
+        TestTemplate('Block 2', tempFile.path, tokens).updateFile();
+      }
       expect(tempFile.readAsStringSync(), '''
 // This is a file with stuff in it.
 // This part shouldn't be changed by
 // the template.
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Block 1
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
 
 static final String tokenFoo = 'foo';
 static final String tokenBar = 'bar';
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Block 1
+
+// BEGIN GENERATED TOKEN PROPERTIES - Block 2
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
+
+static final String tokenFoo = 'bar';
+static final String tokenBar = 'foo';
+
+// END GENERATED TOKEN PROPERTIES - Block 2
+''');
+
+      // Update 'Block 1' again which should just update that block,
+      // leaving 'Block 2' undisturbed.
+      {
+        final Map<String, dynamic> tokens = <String, dynamic>{'version': '0.0', 'foo': 'FOO', 'bar': 'BAR'};
+        TestTemplate('Block 1', tempFile.path, tokens).updateFile();
+      }
+      expect(tempFile.readAsStringSync(), '''
+// This is a file with stuff in it.
+// This part shouldn't be changed by
+// the template.
+
+// BEGIN GENERATED TOKEN PROPERTIES - Block 1
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
+
+static final String tokenFoo = 'FOO';
+static final String tokenBar = 'BAR';
+
+// END GENERATED TOKEN PROPERTIES - Block 1
+
+// BEGIN GENERATED TOKEN PROPERTIES - Block 2
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: 0.0
+
+static final String tokenFoo = 'bar';
+static final String tokenBar = 'foo';
+
+// END GENERATED TOKEN PROPERTIES - Block 2
 ''');
 
     } finally {
@@ -113,14 +244,14 @@ static final String tokenBar = 'bar';
         'family': 'SHAPE_FAMILY_CIRCULAR',
       },
     };
-    final TestTemplate template = TestTemplate('foobar.dart', tokens);
+    final TestTemplate template = TestTemplate('Test', 'foobar.dart', tokens);
     expect(template.shape('foo'), 'const RoundedRectangleBorder(borderRadius: BorderRadius.only(topLeft: Radius.circular(1.0), topRight: Radius.circular(2.0), bottomLeft: Radius.circular(3.0), bottomRight: Radius.circular(4.0)))');
     expect(template.shape('bar'), 'const StadiumBorder()');
   });
 }
 
 class TestTemplate extends TokenTemplate {
-  TestTemplate(super.fileName, super.tokens);
+  TestTemplate(super.blockName, super.fileName, super.tokens);
 
   @override
   String generate() => '''

packages/flutter/lib/src/material/app_bar.dart

@@ -876,7 +876,7 @@ class _AppBarState extends State<AppBar> {
     assert(debugCheckHasMaterialLocalizations(context));
     final ThemeData theme = Theme.of(context);
     final AppBarTheme appBarTheme = AppBarTheme.of(context);
-    final AppBarTheme defaults = theme.useMaterial3 ? _TokenDefaultsM3(context) : _DefaultsM2(context);
+    final AppBarTheme defaults = theme.useMaterial3 ? _AppBarDefaultsM3(context) : _AppBarDefaultsM2(context);
     final ScaffoldState? scaffold = Scaffold.maybeOf(context);
     final ModalRoute<dynamic>? parentRoute = ModalRoute.of(context);
 
@@ -2284,8 +2284,9 @@ mixin _ScrollUnderFlexibleConfig {
   EdgeInsetsGeometry? get expandedTitlePadding;
 }
 
-class _DefaultsM2 extends AppBarTheme {
-  _DefaultsM2(this.context)
+// Hand coded defaults based on Material Design 2.
+class _AppBarDefaultsM2 extends AppBarTheme {
+  _AppBarDefaultsM2(this.context)
     : super(
       elevation: 4.0,
       shadowColor: const Color(0xFF000000),
@@ -2313,15 +2314,17 @@ class _DefaultsM2 extends AppBarTheme {
   TextStyle? get titleTextStyle => _theme.textTheme.headline6;
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - AppBar
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends AppBarTheme {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _AppBarDefaultsM3 extends AppBarTheme {
+  _AppBarDefaultsM3(this.context)
     : super(
       elevation: 0.0,
       scrolledUnderElevation: 3.0,
@@ -2421,4 +2424,4 @@ class _LargeScrollUnderFlexibleConfig with _ScrollUnderFlexibleConfig {
   EdgeInsetsGeometry? get expandedTitlePadding => const EdgeInsets.fromLTRB(16, 0, 16, 28);
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - AppBar

packages/flutter/lib/src/material/card.dart

@@ -161,7 +161,7 @@ class Card extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final CardTheme cardTheme = CardTheme.of(context);
-    final CardTheme defaults = Theme.of(context).useMaterial3 ? _TokenDefaultsM3(context) : _DefaultsM2(context);
+    final CardTheme defaults = Theme.of(context).useMaterial3 ? _CardDefaultsM3(context) : _CardDefaultsM2(context);
 
     return Semantics(
       container: semanticContainer,
@@ -186,8 +186,9 @@ class Card extends StatelessWidget {
   }
 }
 
-class _DefaultsM2 extends CardTheme {
-  const _DefaultsM2(this.context)
+// Hand coded defaults based on Material Design 2.
+class _CardDefaultsM2 extends CardTheme {
+  const _CardDefaultsM2(this.context)
     : super(
         clipBehavior: Clip.none,
         elevation: 1.0,
@@ -206,15 +207,18 @@ class _DefaultsM2 extends CardTheme {
   Color? get shadowColor => Theme.of(context).shadowColor;
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Card
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: v0_101
 
 // Generated version v0_101
-class _TokenDefaultsM3 extends CardTheme {
-  const _TokenDefaultsM3(this.context)
+class _CardDefaultsM3 extends CardTheme {
+  const _CardDefaultsM3(this.context)
     : super(
         clipBehavior: Clip.none,
         elevation: 1.0,
@@ -234,4 +238,4 @@ class _TokenDefaultsM3 extends CardTheme {
   Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Card

packages/flutter/lib/src/material/chip_action.dart

@@ -149,7 +149,7 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ChipThemeData? defaults = Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context, isEnabled)
+      ? _ActionChipDefaultsM3(context, isEnabled)
       : null;
     return RawChip(
       defaultProperties: defaults,
@@ -178,15 +178,17 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - ActionChip
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled)
+// Token database version: v0_101
+
+class _ActionChipDefaultsM3 extends ChipThemeData {
+  const _ActionChipDefaultsM3(this.context, this.isEnabled)
     : super(
         elevation: 0.0,
         shape: const RoundedRectangleBorder(borderRadius: BorderRadius.only(topLeft: Radius.circular(8.0), topRight: Radius.circular(8.0), bottomLeft: Radius.circular(8.0), bottomRight: Radius.circular(8.0))),
@@ -248,4 +250,4 @@ class _TokenDefaultsM3 extends ChipThemeData {
   )!;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - ActionChip

packages/flutter/lib/src/material/chip_choice.dart

@@ -177,7 +177,7 @@ class ChoiceChip extends StatelessWidget
     assert(debugCheckHasMaterial(context));
     final ChipThemeData chipTheme = ChipTheme.of(context);
     final ChipThemeData? defaults = Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context, isEnabled, selected)
+      ? _FilterChipDefaultsM3(context, isEnabled, selected)
       : null;
     return RawChip(
       defaultProperties: defaults,
@@ -211,15 +211,17 @@ class ChoiceChip extends StatelessWidget
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - FilterChip
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled, this.isSelected)
+// Token database version: v0_101
+
+class _FilterChipDefaultsM3 extends ChipThemeData {
+  const _FilterChipDefaultsM3(this.context, this.isEnabled, this.isSelected)
     : super(
         elevation: 0.0,
         shape: const RoundedRectangleBorder(borderRadius: BorderRadius.only(topLeft: Radius.circular(8.0), topRight: Radius.circular(8.0), bottomLeft: Radius.circular(8.0), bottomRight: Radius.circular(8.0))),
@@ -288,4 +290,4 @@ class _TokenDefaultsM3 extends ChipThemeData {
   )!;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - FilterChip

packages/flutter/lib/src/material/chip_filter.dart

@@ -215,7 +215,7 @@ class FilterChip extends StatelessWidget
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ChipThemeData? defaults = Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context, isEnabled, selected)
+      ? _FilterChipDefaultsM3(context, isEnabled, selected)
       : null;
     return RawChip(
       defaultProperties: defaults,
@@ -250,15 +250,17 @@ class FilterChip extends StatelessWidget
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - FilterChip
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled, this.isSelected)
+// Token database version: v0_101
+
+class _FilterChipDefaultsM3 extends ChipThemeData {
+  const _FilterChipDefaultsM3(this.context, this.isEnabled, this.isSelected)
     : super(
         elevation: 0.0,
         shape: const RoundedRectangleBorder(borderRadius: BorderRadius.only(topLeft: Radius.circular(8.0), topRight: Radius.circular(8.0), bottomLeft: Radius.circular(8.0), bottomRight: Radius.circular(8.0))),
@@ -327,4 +329,4 @@ class _TokenDefaultsM3 extends ChipThemeData {
   )!;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - FilterChip

packages/flutter/lib/src/material/chip_input.dart

@@ -206,7 +206,7 @@ class InputChip extends StatelessWidget
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ChipThemeData? defaults = Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context, isEnabled)
+      ? _InputChipDefaultsM3(context, isEnabled)
       : null;
     final Widget? resolvedDeleteIcon = deleteIcon
       ?? (Theme.of(context).useMaterial3 ? const Icon(Icons.clear, size: 18) : null);
@@ -249,15 +249,17 @@ class InputChip extends StatelessWidget
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - InputChip
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ChipThemeData {
-  const _TokenDefaultsM3(this.context, this.isEnabled)
+// Token database version: v0_101
+
+class _InputChipDefaultsM3 extends ChipThemeData {
+  const _InputChipDefaultsM3(this.context, this.isEnabled)
     : super(
         elevation: 0.0,
         shape: const RoundedRectangleBorder(borderRadius: BorderRadius.only(topLeft: Radius.circular(8.0), topRight: Radius.circular(8.0), bottomLeft: Radius.circular(8.0), bottomRight: Radius.circular(8.0))),
@@ -319,4 +321,4 @@ class _TokenDefaultsM3 extends ChipThemeData {
   )!;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - InputChip

packages/flutter/lib/src/material/dialog.dart

@@ -135,7 +135,7 @@ class Dialog extends StatelessWidget {
   Widget build(BuildContext context) {
     final ThemeData theme = Theme.of(context);
     final DialogTheme dialogTheme = DialogTheme.of(context);
-    final DialogTheme defaults = theme.useMaterial3 ? _TokenDefaultsM3(context) : _DefaultsM2(context);
+    final DialogTheme defaults = theme.useMaterial3 ? _DialogDefaultsM3(context) : _DialogDefaultsM2(context);
 
     final EdgeInsets effectivePadding = MediaQuery.of(context).viewInsets + (insetPadding ?? EdgeInsets.zero);
     return AnimatedPadding(
@@ -522,7 +522,7 @@ class AlertDialog extends StatelessWidget {
     assert(debugCheckHasMaterialLocalizations(context));
     final ThemeData theme = Theme.of(context);
     final DialogTheme dialogTheme = DialogTheme.of(context);
-    final DialogTheme defaults = theme.useMaterial3 ? _TokenDefaultsM3(context) : _DefaultsM2(context);
+    final DialogTheme defaults = theme.useMaterial3 ? _DialogDefaultsM3(context) : _DialogDefaultsM2(context);
 
     String? label = semanticLabel;
     switch (theme.platform) {
@@ -1275,12 +1275,9 @@ double _paddingScaleFactor(double textScaleFactor) {
   return lerpDouble(1.0, 1.0 / 3.0, clampedTextScaleFactor - 1.0)!;
 }
 
-// Generate a DialogTheme that represents the M2 default values.
-// This was generated by hand from the previous hand coded defaults
-// for M2. It uses get method overrides instead of properties to
-// avoid computing values that we may not need upfront.
-class _DefaultsM2 extends DialogTheme {
-  _DefaultsM2(this.context)
+// Hand coded defaults based on Material Design 2.
+class _DialogDefaultsM2 extends DialogTheme {
+  _DialogDefaultsM2(this.context)
     : _textTheme = Theme.of(context).textTheme,
       _iconTheme = Theme.of(context).iconTheme,
       super(
@@ -1309,15 +1306,17 @@ class _DefaultsM2 extends DialogTheme {
   EdgeInsetsGeometry? get actionsPadding => EdgeInsets.zero;
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Dialog
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends DialogTheme {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _DialogDefaultsM3 extends DialogTheme {
+  _DialogDefaultsM3(this.context)
     : super(
         alignment: Alignment.center,
         elevation: 6.0,
@@ -1345,4 +1344,4 @@ class _TokenDefaultsM3 extends DialogTheme {
   EdgeInsetsGeometry? get actionsPadding => const EdgeInsets.only(left: 24.0, right: 24.0, bottom: 24.0);
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Dialog

packages/flutter/lib/src/material/elevated_button.dart

@@ -339,7 +339,7 @@ class ElevatedButton extends ButtonStyleButton {
     final ColorScheme colorScheme = theme.colorScheme;
 
     return Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context)
+      ? _ElevatedButtonDefaultsM3(context)
       : styleFrom(
           backgroundColor: colorScheme.primary,
           foregroundColor: colorScheme.onPrimary,
@@ -506,15 +506,17 @@ class _ElevatedButtonWithIconChild extends StatelessWidget {
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - ElevatedButton
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _ElevatedButtonDefaultsM3 extends ButtonStyle {
+  _ElevatedButtonDefaultsM3(this.context)
    : super(
        animationDuration: kThemeChangeDuration,
        enableFeedback: true,
@@ -626,4 +628,4 @@ class _TokenDefaultsM3 extends ButtonStyle {
   InteractiveInkFeatureFactory? get splashFactory => Theme.of(context).splashFactory;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - ElevatedButton

packages/flutter/lib/src/material/elevation_overlay.dart

@@ -151,13 +151,14 @@ class _ElevationOpacity {
   final double opacity;
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - SurfaceTint
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
+// Token database version: v0_101
 
 // Surface tint opacities based on elevations according to the
 // Material Design 3 specification:
@@ -172,4 +173,4 @@ const List<_ElevationOpacity> _surfaceTintElevationOpacities = <_ElevationOpacit
   _ElevationOpacity(12.0, 0.14), // Elevation level 5
 ];
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - SurfaceTint

packages/flutter/lib/src/material/floating_action_button.dart

@@ -513,8 +513,8 @@ class FloatingActionButton extends StatelessWidget {
     final ThemeData theme = Theme.of(context);
     final FloatingActionButtonThemeData floatingActionButtonTheme = theme.floatingActionButtonTheme;
     final FloatingActionButtonThemeData defaults = theme.useMaterial3
-      ? _TokenDefaultsM3(context, _floatingActionButtonType, child != null)
-      : _M2Defaults(context, _floatingActionButtonType, child != null);
+      ? _FABDefaultsM3(context, _floatingActionButtonType, child != null)
+      : _FABDefaultsM2(context, _floatingActionButtonType, child != null);
 
     final Color foregroundColor = this.foregroundColor
       ?? floatingActionButtonTheme.foregroundColor
@@ -727,13 +727,9 @@ class _RenderChildOverflowBox extends RenderAligningShiftedBox {
   }
 }
 
-// Generate a FloatingActionButtonThemeData that represents
-// the M2 default values. This was generated by hand from the
-// previous hand coded defaults for M2. It uses get method overrides
-// instead of properties to avoid computing values that we may not
-// need upfront.
-class _M2Defaults extends FloatingActionButtonThemeData {
-  _M2Defaults(BuildContext context, this.type, this.hasChild)
+// Hand coded defaults based on Material Design 2.
+class _FABDefaultsM2 extends FloatingActionButtonThemeData {
+  _FABDefaultsM2(BuildContext context, this.type, this.hasChild)
       : _theme = Theme.of(context),
         _colors = Theme.of(context).colorScheme,
         super(
@@ -780,15 +776,17 @@ class _M2Defaults extends FloatingActionButtonThemeData {
   @override TextStyle? get extendedTextStyle => _theme.textTheme.button!.copyWith(letterSpacing: 1.2);
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - FAB
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends FloatingActionButtonThemeData {
-  _TokenDefaultsM3(this.context, this.type, this.hasChild)
+// Token database version: v0_101
+
+class _FABDefaultsM3 extends FloatingActionButtonThemeData {
+  _FABDefaultsM3(this.context, this.type, this.hasChild)
     : super(
         elevation: 6.0,
         focusElevation: 6.0,
@@ -855,4 +853,4 @@ class _TokenDefaultsM3 extends FloatingActionButtonThemeData {
   @override TextStyle? get extendedTextStyle => _textTheme.labelLarge;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - FAB

packages/flutter/lib/src/material/icon_button.dart

@@ -775,7 +775,7 @@ class _IconButtonM3 extends ButtonStyleButton {
   /// * `splashFactory` - Theme.splashFactory
   @override
   ButtonStyle defaultStyleOf(BuildContext context) {
-    return _TokenDefaultsM3(context);
+    return _IconButtonDefaultsM3(context);
   }
 
   /// Returns null because [IconButton] doesn't have its component theme.
@@ -883,15 +883,17 @@ class _IconButtonDefaultMouseCursor extends MaterialStateProperty<MouseCursor> w
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - IconButton
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _IconButtonDefaultsM3 extends ButtonStyle {
+  _IconButtonDefaultsM3(this.context)
     : super(
         animationDuration: kThemeChangeDuration,
         enableFeedback: true,
@@ -992,4 +994,4 @@ class _TokenDefaultsM3 extends ButtonStyle {
   InteractiveInkFeatureFactory? get splashFactory => Theme.of(context).splashFactory;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - IconButton

packages/flutter/lib/src/material/navigation_bar.dart

@@ -1173,11 +1173,12 @@ bool _isForwardOrCompleted(Animation<double> animation) {
 }
 
 NavigationBarThemeData _defaultsFor(BuildContext context) {
-  return Theme.of(context).useMaterial3 ? _TokenDefaultsM3(context) : _Defaults(context);
+  return Theme.of(context).useMaterial3 ? _NavigationBarDefaultsM3(context) : _NavigationBarDefaultsM2(context);
 }
 
-class _Defaults extends NavigationBarThemeData {
-  _Defaults(BuildContext context)
+// Hand coded defaults based on Material Design 2.
+class _NavigationBarDefaultsM2 extends NavigationBarThemeData {
+  _NavigationBarDefaultsM2(BuildContext context)
       : _theme = Theme.of(context),
         _colors = Theme.of(context).colorScheme,
         super(
@@ -1190,7 +1191,7 @@ class _Defaults extends NavigationBarThemeData {
   final ThemeData _theme;
   final ColorScheme _colors;
 
-  // With Material 3, the NavigationBar uses an overlay blend for the
+  // With Material 2, the NavigationBar uses an overlay blend for the
   // default color regardless of light/dark mode.
   @override Color? get backgroundColor => ElevationOverlay.colorWithOverlay(_colors.surface, _colors.onSurface, 3.0);
 
@@ -1206,15 +1207,17 @@ class _Defaults extends NavigationBarThemeData {
   @override MaterialStateProperty<TextStyle?>? get labelTextStyle => MaterialStatePropertyAll<TextStyle?>(_theme.textTheme.overline!.copyWith(color: _colors.onSurface));
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - NavigationBar
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends NavigationBarThemeData {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _NavigationBarDefaultsM3 extends NavigationBarThemeData {
+  _NavigationBarDefaultsM3(this.context)
       : super(
           height: 80.0,
           elevation: 3.0,
@@ -1254,4 +1257,4 @@ class _TokenDefaultsM3 extends NavigationBarThemeData {
   }
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - NavigationBar

packages/flutter/lib/src/material/navigation_rail.dart

@@ -379,7 +379,7 @@ class _NavigationRailState extends State<NavigationRail> with TickerProviderStat
   @override
   Widget build(BuildContext context) {
     final NavigationRailThemeData navigationRailTheme = NavigationRailTheme.of(context);
-    final NavigationRailThemeData defaults = Theme.of(context).useMaterial3 ? _TokenDefaultsM3(context) : _DefaultsM2(context);
+    final NavigationRailThemeData defaults = Theme.of(context).useMaterial3 ? _NavigationRailDefaultsM3(context) : _NavigationRailDefaultsM2(context);
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
 
     final Color backgroundColor = widget.backgroundColor ?? navigationRailTheme.backgroundColor ?? defaults.backgroundColor!;
@@ -910,8 +910,9 @@ const Widget _verticalSpacer = SizedBox(height: 8.0);
 const double _verticalIconLabelSpacingM3 = 4.0;
 const double _verticalDestinationSpacingM3 = 12.0;
 
-class _DefaultsM2 extends NavigationRailThemeData {
-  _DefaultsM2(BuildContext context)
+// Hand coded defaults based on Material Design 2.
+class _NavigationRailDefaultsM2 extends NavigationRailThemeData {
+  _NavigationRailDefaultsM2(BuildContext context)
       : _theme = Theme.of(context),
         _colors = Theme.of(context).colorScheme,
         super(
@@ -953,15 +954,17 @@ class _DefaultsM2 extends NavigationRailThemeData {
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - NavigationRail
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends NavigationRailThemeData {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _NavigationRailDefaultsM3 extends NavigationRailThemeData {
+  _NavigationRailDefaultsM3(this.context)
       : super(
           elevation: 0.0,
           groupAlignment: -1,
@@ -1003,4 +1006,4 @@ class _TokenDefaultsM3 extends NavigationRailThemeData {
 
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - NavigationRail

packages/flutter/lib/src/material/outlined_button.dart

@@ -306,7 +306,7 @@ class OutlinedButton extends ButtonStyleButton {
     final ColorScheme colorScheme = theme.colorScheme;
 
     return Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context)
+      ? _OutlinedButtonDefaultsM3(context)
       : styleFrom(
           foregroundColor: colorScheme.primary,
           disabledForegroundColor: colorScheme.onSurface.withOpacity(0.38),
@@ -438,15 +438,17 @@ class _OutlinedButtonWithIconChild extends StatelessWidget {
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - OutlinedButton
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _OutlinedButtonDefaultsM3 extends ButtonStyle {
+  _OutlinedButtonDefaultsM3(this.context)
    : super(
        animationDuration: kThemeChangeDuration,
        enableFeedback: true,
@@ -542,4 +544,4 @@ class _TokenDefaultsM3 extends ButtonStyle {
   InteractiveInkFeatureFactory? get splashFactory => Theme.of(context).splashFactory;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - OutlinedButton

packages/flutter/lib/src/material/text_button.dart

@@ -327,7 +327,7 @@ class TextButton extends ButtonStyleButton {
     final ColorScheme colorScheme = theme.colorScheme;
 
     return Theme.of(context).useMaterial3
-      ? _TokenDefaultsM3(context)
+      ? _TextButtonDefaultsM3(context)
       : styleFrom(
           foregroundColor: colorScheme.primary,
           disabledForegroundColor: colorScheme.onSurface.withOpacity(0.38),
@@ -483,15 +483,17 @@ class _TextButtonWithIconChild extends StatelessWidget {
   }
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - TextButton
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
 
-// Generated version v0_101
-class _TokenDefaultsM3 extends ButtonStyle {
-  _TokenDefaultsM3(this.context)
+// Token database version: v0_101
+
+class _TextButtonDefaultsM3 extends ButtonStyle {
+  _TextButtonDefaultsM3(this.context)
    : super(
        animationDuration: kThemeChangeDuration,
        enableFeedback: true,
@@ -580,4 +582,4 @@ class _TokenDefaultsM3 extends ButtonStyle {
   InteractiveInkFeatureFactory? get splashFactory => Theme.of(context).splashFactory;
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - TextButton

packages/flutter/lib/src/material/typography.dart

@@ -729,13 +729,15 @@ class Typography with Diagnosticable {
   static const TextTheme tall2021 = _M3Typography.tall;
 }
 
-// BEGIN GENERATED TOKEN PROPERTIES
+// BEGIN GENERATED TOKEN PROPERTIES - Typography
 
-// Generated code to the end of this file. Do not edit by hand.
-// These defaults are generated from the Material Design Token
-// database by the script dev/tools/gen_defaults/bin/gen_defaults.dart.
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: v0_101
 
-// Generated version v0_101
 class _M3Typography {
   _M3Typography._();
 
@@ -794,4 +796,4 @@ class _M3Typography {
   );
 }
 
-// END GENERATED TOKEN PROPERTIES
+// END GENERATED TOKEN PROPERTIES - Typography