Add fontFamilyFallback to ThemeData (#112976)

Add missing parameters to ThemeData (fontFamilyFallback and package)

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

@@ -616,6 +616,8 @@ class TextTheme with Diagnosticable {
   /// point.
   TextTheme apply({
     String? fontFamily,
+    List<String>? fontFamilyFallback,
+    String? package,
     double fontSizeFactor = 1.0,
     double fontSizeDelta = 0.0,
     Color? displayColor,
@@ -631,8 +633,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       displayMedium: displayMedium?.apply(
         color: displayColor,
@@ -640,8 +644,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       displaySmall: displaySmall?.apply(
         color: displayColor,
@@ -649,8 +655,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       headlineLarge: headlineLarge?.apply(
         color: displayColor,
@@ -658,8 +666,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       headlineMedium: headlineMedium?.apply(
         color: displayColor,
@@ -667,8 +677,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       headlineSmall: headlineSmall?.apply(
         color: bodyColor,
@@ -676,8 +688,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       titleLarge: titleLarge?.apply(
         color: bodyColor,
@@ -685,8 +699,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       titleMedium: titleMedium?.apply(
         color: bodyColor,
@@ -694,8 +710,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       titleSmall: titleSmall?.apply(
         color: bodyColor,
@@ -703,8 +721,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       bodyLarge: bodyLarge?.apply(
         color: bodyColor,
@@ -712,8 +732,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       bodyMedium: bodyMedium?.apply(
         color: bodyColor,
@@ -721,8 +743,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       bodySmall: bodySmall?.apply(
         color: displayColor,
@@ -730,8 +754,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       labelLarge: labelLarge?.apply(
         color: bodyColor,
@@ -739,8 +765,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       labelMedium: labelMedium?.apply(
         color: bodyColor,
@@ -748,8 +776,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
       labelSmall: labelSmall?.apply(
         color: bodyColor,
@@ -757,8 +787,10 @@ class TextTheme with Diagnosticable {
         decorationColor: decorationColor,
         decorationStyle: decorationStyle,
         fontFamily: fontFamily,
+        fontFamilyFallback: fontFamilyFallback,
         fontSizeFactor: fontSizeFactor,
         fontSizeDelta: fontSizeDelta,
+        package: package,
       ),
     );
   }

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

@@ -322,6 +322,8 @@ class ThemeData with Diagnosticable {
     Color? unselectedWidgetColor,
     // TYPOGRAPHY & ICONOGRAPHY
     String? fontFamily,
+    List<String>? fontFamilyFallback,
+    String? package,
     IconThemeData? iconTheme,
     IconThemeData? primaryIconTheme,
     TextTheme? primaryTextTheme,
@@ -561,6 +563,16 @@ class ThemeData with Diagnosticable {
       defaultPrimaryTextTheme = defaultPrimaryTextTheme.apply(fontFamily: fontFamily);
       defaultAccentTextTheme = defaultAccentTextTheme.apply(fontFamily: fontFamily);
     }
+    if (fontFamilyFallback != null) {
+      defaultTextTheme = defaultTextTheme.apply(fontFamilyFallback: fontFamilyFallback);
+      defaultPrimaryTextTheme = defaultPrimaryTextTheme.apply(fontFamilyFallback: fontFamilyFallback);
+      defaultAccentTextTheme = defaultAccentTextTheme.apply(fontFamilyFallback: fontFamilyFallback);
+    }
+    if (package != null) {
+      defaultTextTheme = defaultTextTheme.apply(package: package);
+      defaultPrimaryTextTheme = defaultPrimaryTextTheme.apply(package: package);
+      defaultAccentTextTheme = defaultAccentTextTheme.apply(package: package);
+    }
     textTheme = defaultTextTheme.merge(textTheme);
     primaryTextTheme = defaultPrimaryTextTheme.merge(primaryTextTheme);
     iconTheme ??= isDark ? const IconThemeData(color: kDefaultIconLightColor) : const IconThemeData(color: kDefaultIconDarkColor);

packages/flutter/test/material/text_theme_test.dart

@@ -79,6 +79,7 @@ void main() {
     const Color displayColor = Color(0x00000001);
     const Color bodyColor = Color(0x00000002);
     const String fontFamily = 'fontFamily';
+    const List<String> fontFamilyFallback = <String>['font', 'family', 'fallback'];
     const Color decorationColor = Color(0x00000003);
     const TextDecorationStyle decorationStyle = TextDecorationStyle.dashed;
     final TextDecoration decoration = TextDecoration.combine(<TextDecoration>[
@@ -89,6 +90,7 @@ void main() {
     final Typography typography = Typography.material2018();
     final TextTheme theme = typography.black.apply(
       fontFamily: fontFamily,
+      fontFamilyFallback: fontFamilyFallback,
       displayColor: displayColor,
       bodyColor: bodyColor,
       decoration: decoration,
@@ -130,6 +132,7 @@ void main() {
       theme.labelSmall!,
     ];
     expect(themeStyles.every((TextStyle style) => style.fontFamily == fontFamily), true);
+    expect(themeStyles.every((TextStyle style) => style.fontFamilyFallback == fontFamilyFallback), true);
     expect(themeStyles.every((TextStyle style) => style.decorationColor == decorationColor), true);
     expect(themeStyles.every((TextStyle style) => style.decorationStyle == decorationStyle), true);
     expect(themeStyles.every((TextStyle style) => style.decoration == decoration), true);

packages/flutter/test/widgets/text_test.dart

@@ -865,6 +865,39 @@ void main() {
     semantics.dispose();
   }, skip: isBrowser); // https://github.com/flutter/flutter/issues/62945
 
+  testWidgets('receives fontFamilyFallback and package from root ThemeData', (WidgetTester tester) async {
+    const String fontFamily = 'fontFamily';
+    const String package = 'package_name';
+    final List<String> fontFamilyFallback = <String>['font', 'family', 'fallback'];
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(
+          fontFamily: fontFamily,
+          fontFamilyFallback: fontFamilyFallback,
+          package: package,
+          primarySwatch: Colors.blue,
+        ),
+        home: const Scaffold(
+          body: Center(
+            child: Text(
+              'foo',
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(find.byType(RichText), findsOneWidget);
+    final RichText richText = tester.widget(find.byType(RichText));
+    final InlineSpan text = richText.text;
+    final TextStyle? style = text.style;
+    expect(style?.fontFamily, equals('packages/$package/$fontFamily'));
+    for (int i = 0; i < fontFamilyFallback.length; i++) {
+      final String fallback = fontFamilyFallback[i];
+      expect(style?.fontFamilyFallback?[i], equals('packages/$package/$fallback'));
+    }
+  });
+
   testWidgets('Overflow is clipping correctly - short text with overflow: clip', (WidgetTester tester) async {
     await _pumpTextWidget(
       tester: tester,