Introduce Material 3 year2023 flag to ProgressIndicatorThemeData (#159720)

Related to [Introduce Material 3 `year2023` flag to the updated widget
themes](https://github.com/flutter/flutter/issues/159484)


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we expect every widget to implement].
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- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

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

@@ -353,7 +353,7 @@ class LinearProgressIndicator extends ProgressIndicator {
       'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
       'This feature was deprecated after v3.26.0-0.1.pre.'
     )
-    this.year2023 = true,
+    this.year2023,
   }) : assert(minHeight == null || minHeight > 0);
 
   /// {@template flutter.material.LinearProgressIndicator.trackColor}
@@ -416,18 +416,21 @@ class LinearProgressIndicator extends ProgressIndicator {
   /// If that is null, then defaults to 4.
   final double? trackGap;
 
-  /// When true, the [LinearProgressIndicator] will use the 2023 Material 3
+  /// When true, the [LinearProgressIndicator] will use the 2023 Material Design 3
-  /// Design appearance.
+  /// appearance.
   ///
-  /// Defaults to true. If false, the [LinearProgressIndicator] will use the
+  /// If null, then the [ProgressIndicatorThemeData.year2023] will be used.
-  /// latest Material 3 Design appearance, which was introduced in December 2023.
+  /// If that is null, then defaults to true.
+  ///
+  /// If this is set to false, the [LinearProgressIndicator] will use the
+  /// latest Material Design 3 appearance, which was introduced in December 2023.
   ///
   /// If [ThemeData.useMaterial3] is false, then this property is ignored.
   @Deprecated(
     'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
     'This feature was deprecated after v3.27.0-0.1.pre.'
   )
-  final bool year2023;
+  final bool? year2023;
 
   @override
   State<LinearProgressIndicator> createState() => _LinearProgressIndicatorState();
@@ -465,14 +468,14 @@ class _LinearProgressIndicatorState extends State<LinearProgressIndicator> with
   }
 
   Widget _buildIndicator(BuildContext context, double animationValue, TextDirection textDirection) {
+    final ProgressIndicatorThemeData indicatorTheme = ProgressIndicatorTheme.of(context);
+    final bool year2023 = widget.year2023 ?? indicatorTheme.year2023 ?? true;
     final ProgressIndicatorThemeData defaults = switch (Theme.of(context).useMaterial3) {
-      true => widget.year2023
+      true => year2023
         ? _LinearProgressIndicatorDefaultsM3Year2023(context)
         : _LinearProgressIndicatorDefaultsM3(context),
       false => _LinearProgressIndicatorDefaultsM2(context),
     };
-
-    final ProgressIndicatorThemeData indicatorTheme = ProgressIndicatorTheme.of(context);
     final Color trackColor = widget.backgroundColor ??
       indicatorTheme.linearTrackColor ??
       defaults.linearTrackColor!;
@@ -482,17 +485,17 @@ class _LinearProgressIndicatorState extends State<LinearProgressIndicator> with
     final BorderRadiusGeometry? borderRadius = widget.borderRadius
       ?? indicatorTheme.borderRadius
       ?? defaults.borderRadius;
-    final Color? stopIndicatorColor = !widget.year2023
+    final Color? stopIndicatorColor = !year2023
       ? widget.stopIndicatorColor ??
         indicatorTheme.stopIndicatorColor ??
         defaults.stopIndicatorColor
       : null;
-    final double? stopIndicatorRadius = !widget.year2023
+    final double? stopIndicatorRadius = !year2023
       ? widget.stopIndicatorRadius ??
         indicatorTheme.stopIndicatorRadius ??
         defaults.stopIndicatorRadius
       : null;
-    final double? trackGap = !widget.year2023
+    final double? trackGap = !year2023
       ? widget.trackGap ??
         indicatorTheme.trackGap ??
         defaults.trackGap
@@ -748,7 +751,7 @@ class CircularProgressIndicator extends ProgressIndicator {
       'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
       'This feature was deprecated after v3.27.0-0.1.pre.'
     )
-    this.year2023 = true,
+    this.year2023,
     this.padding,
   }) : _indicatorType = _ActivityIndicatorType.material;
 
@@ -778,7 +781,7 @@ class CircularProgressIndicator extends ProgressIndicator {
       'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
       'This feature was deprecated after v3.27.0-0.2.pre.'
     )
-    this.year2023 = true,
+    this.year2023,
     this.padding,
   }) : _indicatorType = _ActivityIndicatorType.adaptive;
 
@@ -847,18 +850,21 @@ class CircularProgressIndicator extends ProgressIndicator {
   /// If that is null, then defaults to 4.
   final double? trackGap;
 
-  /// When true, the [CircularProgressIndicator] will use the 2023 Material 3
+  /// When true, the [CircularProgressIndicator] will use the 2023 Material Design 3
-  /// Design appearance.
+  /// appearance.
   ///
-  /// Defaults to true. If false, the [CircularProgressIndicator] will use the
+  /// If null, then the [ProgressIndicatorThemeData.year2023] will be used.
-  /// latest Material 3 Design appearance, which was introduced in December 2023.
+  /// If that is null, then defaults to true.
+  ///
+  /// If this is set to false, the [CircularProgressIndicator] will use the
+  /// latest Material Design 3 appearance, which was introduced in December 2023.
   ///
   /// If [ThemeData.useMaterial3] is false, then this property is ignored.
   @Deprecated(
     'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
     'This feature was deprecated after v3.27.0-0.2.pre.'
   )
-  final bool year2023;
+  final bool? year2023;
 
   /// The padding around the indicator track.
   ///
@@ -954,13 +960,14 @@ class _CircularProgressIndicatorState extends State<CircularProgressIndicator> w
   }
 
   Widget _buildMaterialIndicator(BuildContext context, double headValue, double tailValue, double offsetValue, double rotationValue) {
+    final ProgressIndicatorThemeData indicatorTheme = ProgressIndicatorTheme.of(context);
+    final bool year2023 = widget.year2023 ?? indicatorTheme.year2023 ?? true;
     final ProgressIndicatorThemeData defaults = switch (Theme.of(context).useMaterial3) {
-      true => widget.year2023
+      true => year2023
         ? _CircularProgressIndicatorDefaultsM3Year2023(context, indeterminate: widget.value == null)
         : _CircularProgressIndicatorDefaultsM3(context, indeterminate: widget.value == null),
       false => _CircularProgressIndicatorDefaultsM2(context, indeterminate: widget.value == null),
     };
-    final ProgressIndicatorThemeData indicatorTheme = ProgressIndicatorTheme.of(context);
     final Color? trackColor = widget.backgroundColor
       ?? indicatorTheme.circularTrackColor
       ?? defaults.circularTrackColor;
@@ -975,7 +982,7 @@ class _CircularProgressIndicatorState extends State<CircularProgressIndicator> w
     final BoxConstraints constraints = widget.constraints
       ?? indicatorTheme.constraints
       ?? defaults.constraints!;
-    final double? trackGap = widget.year2023
+    final double? trackGap = year2023
       ? null
       : widget.trackGap ??
         indicatorTheme.trackGap ??
@@ -999,7 +1006,7 @@ class _CircularProgressIndicatorState extends State<CircularProgressIndicator> w
           strokeAlign: strokeAlign,
           strokeCap: strokeCap,
           trackGap: trackGap,
-          year2023: widget.year2023,
+          year2023: year2023,
         ),
       ),
     );

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

@@ -48,6 +48,11 @@ class ProgressIndicatorThemeData with Diagnosticable {
     this.constraints,
     this.trackGap,
     this.circularTrackPadding,
+    @Deprecated(
+      'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
+      'This feature was deprecated after v3.27.0-0.2.pre.'
+    )
+    this.year2023,
   });
 
   /// The color of the [ProgressIndicator]'s indicator.
@@ -114,6 +119,23 @@ class ProgressIndicatorThemeData with Diagnosticable {
   /// Overrides the padding of the [CircularProgressIndicator].
   final EdgeInsetsGeometry? circularTrackPadding;
 
+  /// Overrides the [CircularProgressIndicator.year2023] and
+  /// [LinearProgressIndicator.year2023] properties.
+  ///
+  /// When true, the [CircularProgressIndicator] and [LinearProgressIndicator]
+  /// will use the 2023 Material Design 3 appearance. Defaults to true.
+  ///
+  /// If this is set to false, the [CircularProgressIndicator] and
+  /// [LinearProgressIndicator] will use the latest Material Design 3 appearance,
+  /// which was introduced in December 2023.
+  ///
+  /// If [ThemeData.useMaterial3] is false, then this property is ignored.
+  @Deprecated(
+    'Use ProgressIndicatorTheme to customize the ProgressIndicator appearance. '
+    'This feature was deprecated after v3.27.0-0.2.pre.'
+  )
+  final bool? year2023;
+
   /// Creates a copy of this object but with the given fields replaced with the
   /// new values.
   ProgressIndicatorThemeData copyWith({
@@ -131,6 +153,7 @@ class ProgressIndicatorThemeData with Diagnosticable {
     BoxConstraints? constraints,
     double? trackGap,
     EdgeInsetsGeometry? circularTrackPadding,
+    bool? year2023,
   }) {
     return ProgressIndicatorThemeData(
       color: color ?? this.color,
@@ -147,6 +170,7 @@ class ProgressIndicatorThemeData with Diagnosticable {
       constraints: constraints ?? this.constraints,
       trackGap : trackGap ?? this.trackGap,
       circularTrackPadding: circularTrackPadding ?? this.circularTrackPadding,
+      year2023: year2023 ?? this.year2023,
     );
   }
 
@@ -172,6 +196,7 @@ class ProgressIndicatorThemeData with Diagnosticable {
       constraints: BoxConstraints.lerp(a?.constraints, b?.constraints, t),
       trackGap : lerpDouble(a?.trackGap, b?.trackGap, t),
       circularTrackPadding: EdgeInsetsGeometry.lerp(a?.circularTrackPadding, b?.circularTrackPadding, t),
+      year2023: t < 0.5 ? a?.year2023 : b?.year2023,
     );
   }
 
@@ -191,6 +216,7 @@ class ProgressIndicatorThemeData with Diagnosticable {
     constraints,
     trackGap,
     circularTrackPadding,
+    year2023,
   );
 
   @override
@@ -215,7 +241,8 @@ class ProgressIndicatorThemeData with Diagnosticable {
       && other.strokeCap == strokeCap
       && other.constraints == constraints
       && other.trackGap == trackGap
-      && other.circularTrackPadding == circularTrackPadding;
+      && other.circularTrackPadding == circularTrackPadding
+      && other.year2023 == year2023;
   }
 
   @override
@@ -235,6 +262,7 @@ class ProgressIndicatorThemeData with Diagnosticable {
     properties.add(DiagnosticsProperty<BoxConstraints>('constraints', constraints, defaultValue: null));
     properties.add(DoubleProperty('trackGap', trackGap, defaultValue: null));
     properties.add(DiagnosticsProperty<EdgeInsetsGeometry>('circularTrackPadding', circularTrackPadding, defaultValue: null));
+    properties.add(DiagnosticsProperty<bool>('year2023', year2023, defaultValue: null));
   }
 }
 

packages/flutter/test/material/progress_indicator_test.dart

@@ -1540,6 +1540,8 @@ void main() {
           rrect: RRect.fromLTRBR(100.0 + customTrackGap, 0.0, 200.0, 4.0, const Radius.circular(2.0)),
           color: theme.colorScheme.secondaryContainer,
         )
+        // Stop indicator.
+        ..circle()
         // Active track.
         ..rrect(
           rrect: RRect.fromLTRBR(0.0, 0.0, 100.0, 4.0, const Radius.circular(2.0)),
@@ -1557,6 +1559,8 @@ void main() {
           rrect: RRect.fromLTRBR(0.0, 0.0, 200.0, 4.0, const Radius.circular(2.0)),
           color: theme.colorScheme.secondaryContainer,
         )
+        // Stop indicator.
+        ..circle()
         // Active indicator.
         ..rrect(
           rrect: RRect.fromLTRBR(0.0, 0.0, 100.0, 4.0, const Radius.circular(2.0)),

packages/flutter/test/material/progress_indicator_theme_test.dart

@@ -41,6 +41,7 @@ void main() {
       constraints: BoxConstraints.tightFor(width: 80.0, height: 80.0),
       trackGap: 16.0,
       circularTrackPadding: EdgeInsets.all(12.0),
+      year2023: false
     ).debugFillProperties(builder);
 
     final List<String> description = builder.properties
@@ -62,7 +63,8 @@ void main() {
       'strokeCap: StrokeCap.butt',
       'constraints: BoxConstraints(w=80.0, h=80.0)',
       'trackGap: 16.0',
-      'circularTrackPadding: EdgeInsets.all(12.0)'
+      'circularTrackPadding: EdgeInsets.all(12.0)',
+      'year2023: false',
     ]));
   });
 
@@ -361,4 +363,178 @@ void main() {
       matchesGoldenFile('circular_progress_indicator_theme_year2023_false.png'),
     );
   });
+
+  testWidgets('Opt into 2024 CircularProgressIndicator appearance with ProgressIndicatorThemeData.year2023', (WidgetTester tester) async {
+    final ThemeData theme = ThemeData(
+      progressIndicatorTheme: const ProgressIndicatorThemeData(
+        year2023: false,
+      ),
+    );
+    const EdgeInsetsGeometry padding = EdgeInsets.all(4.0);
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: const Scaffold(
+          body: Center(
+            child: CircularProgressIndicator(value: 0.5),
+          ),
+        ),
+      ),
+    );
+
+    final Size indicatorBoxSize = tester.getSize(find.descendant(
+      of: find.byType(CircularProgressIndicator),
+      matching: find.byType(ConstrainedBox),
+    ));
+    expect(
+      tester.getSize(find.byType(CircularProgressIndicator)),
+      equals(Size(
+        indicatorBoxSize.width + padding.horizontal,
+        indicatorBoxSize.height + padding.vertical,
+      )),
+    );
+    expect(
+      find.byType(CircularProgressIndicator),
+      paints
+        // Track.
+        ..arc(
+          rect: const Rect.fromLTRB(2.0, 2.0, 38.0, 38.0),
+          color: theme.colorScheme.secondaryContainer,
+          strokeWidth: 4.0,
+          strokeCap: StrokeCap.round,
+          style: PaintingStyle.stroke,
+        )
+        // Active indicator.
+        ..arc(
+          rect: const Rect.fromLTRB(2.0, 2.0, 38.0, 38.0),
+          color: theme.colorScheme.primary,
+          strokeWidth: 4.0,
+          strokeCap: StrokeCap.round,
+          style: PaintingStyle.stroke,
+        ),
+    );
+    await expectLater(
+      find.byType(CircularProgressIndicator),
+      matchesGoldenFile('circular_progress_indicator_theme_opt_into_2024.png'),
+    );
+  });
+
+  testWidgets('CircularProgressIndicator.year2023 overrides ProgressIndicatorThemeData.year2023', (WidgetTester tester) async {
+    final ThemeData theme = ThemeData(
+      progressIndicatorTheme: const ProgressIndicatorThemeData(
+        year2023: false,
+      ),
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: const Scaffold(
+          body: Center(
+            child: CircularProgressIndicator(
+              year2023: true,
+              value: 0.5,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final Size indicatorBoxSize = tester.getSize(find.descendant(
+      of: find.byType(CircularProgressIndicator),
+      matching: find.byType(ConstrainedBox),
+    ));
+    expect(
+      tester.getSize(find.byType(CircularProgressIndicator)),
+      equals(indicatorBoxSize),
+    );
+    expect(
+      find.byType(CircularProgressIndicator),
+      paints
+        // Active indicator.
+        ..arc(
+          rect: const Rect.fromLTRB(-0.0, -0.0, 36.0, 36.0),
+          color: theme.colorScheme.primary,
+          strokeWidth: 4.0,
+          style: PaintingStyle.stroke,
+        ),
+    );
+    await expectLater(
+      find.byType(CircularProgressIndicator),
+      matchesGoldenFile('circular_progress_indicator_theme_opt_into_2024_override.png'),
+    );
+  });
+
+  testWidgets('Opt into 2024 LinearProgressIndicator appearance with ProgressIndicatorThemeData.year2023', (WidgetTester tester) async {
+    final ThemeData theme = ThemeData(
+      progressIndicatorTheme: const ProgressIndicatorThemeData(
+        year2023: false,
+      ),
+    );
+    const double defaultTrackGap = 4.0;
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: const Scaffold(
+          body: SizedBox(
+            width: 200.0,
+            child: LinearProgressIndicator(value: 0.5),
+          ),
+        ),
+      ),
+    );
+
+    expect(
+      find.byType(LinearProgressIndicator),
+      paints
+        // Track.
+        ..rrect(
+          rrect: RRect.fromLTRBR(100.0 + defaultTrackGap, 0.0, 200.0, 4.0, const Radius.circular(2.0)),
+          color: theme.colorScheme.secondaryContainer,
+        )
+        // Stop indicator.
+        ..circle(x: 198.0, y: 2.0, radius: 2.0, color: theme.colorScheme.primary)
+        // Active track.
+        ..rrect(
+          rrect: RRect.fromLTRBR(0.0, 0.0, 100.0, 4.0, const Radius.circular(2.0)),
+          color: theme.colorScheme.primary,
+        ),
+    );
+  });
+
+  testWidgets('LinearProgressIndicator.year2023 overrides ProgressIndicatorThemeData.year2023', (WidgetTester tester) async {
+    final ThemeData theme = ThemeData(
+      progressIndicatorTheme: const ProgressIndicatorThemeData(
+        year2023: false,
+      ),
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: const Scaffold(
+          body: SizedBox(
+            width: 200.0,
+            child: LinearProgressIndicator(
+              year2023: true,
+              value: 0.5,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(
+      find.byType(LinearProgressIndicator),
+      paints
+        // Track.
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 200.0, 4.0),
+          color: theme.colorScheme.secondaryContainer,
+        )
+        // Active track.
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 100.0, 4.0),
+          color: theme.colorScheme.primary,
+        ),
+    );
+  });
 }