Fixed TimeOfDay.hourOfPeriod for the noon and midnight cases. (#83947)

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

@@ -92,7 +92,9 @@ class TimeOfDay {
   DayPeriod get period => hour < hoursPerPeriod ? DayPeriod.am : DayPeriod.pm;
 
   /// Which hour of the current period (e.g., am or pm) this time is.
-  int get hourOfPeriod => hour - periodOffset;
+  ///
+  /// For 12AM (midnight) and 12PM (noon) this returns 12.
+  int get hourOfPeriod => hour == 0 || hour == 12 ? 12 : hour - periodOffset;
 
   /// The hour at which the current period starts.
   int get periodOffset => period == DayPeriod.am ? 0 : hoursPerPeriod;

packages/flutter/test/material/time_test.dart

@@ -27,6 +27,34 @@ void main() {
     });
   });
 
+  testWidgets('hourOfPeriod returns correct value', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/59158.
+    expect(const TimeOfDay(minute: 0, hour:  0).hourOfPeriod, 12);
+    expect(const TimeOfDay(minute: 0, hour:  1).hourOfPeriod,  1);
+    expect(const TimeOfDay(minute: 0, hour:  2).hourOfPeriod,  2);
+    expect(const TimeOfDay(minute: 0, hour:  3).hourOfPeriod,  3);
+    expect(const TimeOfDay(minute: 0, hour:  4).hourOfPeriod,  4);
+    expect(const TimeOfDay(minute: 0, hour:  5).hourOfPeriod,  5);
+    expect(const TimeOfDay(minute: 0, hour:  6).hourOfPeriod,  6);
+    expect(const TimeOfDay(minute: 0, hour:  7).hourOfPeriod,  7);
+    expect(const TimeOfDay(minute: 0, hour:  8).hourOfPeriod,  8);
+    expect(const TimeOfDay(minute: 0, hour:  9).hourOfPeriod,  9);
+    expect(const TimeOfDay(minute: 0, hour: 10).hourOfPeriod, 10);
+    expect(const TimeOfDay(minute: 0, hour: 11).hourOfPeriod, 11);
+    expect(const TimeOfDay(minute: 0, hour: 12).hourOfPeriod, 12);
+    expect(const TimeOfDay(minute: 0, hour: 13).hourOfPeriod,  1);
+    expect(const TimeOfDay(minute: 0, hour: 14).hourOfPeriod,  2);
+    expect(const TimeOfDay(minute: 0, hour: 15).hourOfPeriod,  3);
+    expect(const TimeOfDay(minute: 0, hour: 16).hourOfPeriod,  4);
+    expect(const TimeOfDay(minute: 0, hour: 17).hourOfPeriod,  5);
+    expect(const TimeOfDay(minute: 0, hour: 18).hourOfPeriod,  6);
+    expect(const TimeOfDay(minute: 0, hour: 19).hourOfPeriod,  7);
+    expect(const TimeOfDay(minute: 0, hour: 20).hourOfPeriod,  8);
+    expect(const TimeOfDay(minute: 0, hour: 21).hourOfPeriod,  9);
+    expect(const TimeOfDay(minute: 0, hour: 22).hourOfPeriod, 10);
+    expect(const TimeOfDay(minute: 0, hour: 23).hourOfPeriod, 11);
+  });
+
   group('RestorableTimeOfDay tests', () {
     testWidgets('value is not accessible when not registered', (WidgetTester tester) async {
       expect(() => RestorableTimeOfDay(const TimeOfDay(hour: 20, minute: 4)).value, throwsAssertionError);