perf(updater): finite pulse for the update chip (#1554)

lib/features/updater/update_available_badge.dart

@@ -16,7 +16,14 @@ import 'package:shadcn_flutter/shadcn_flutter.dart' hide TextExtension;
 /// [QueryaMotion.effectiveDuration]; Off / OS `disableAnimations` stop the pulse.
 const Duration kUpdateBadgePulsePeriod = Duration(milliseconds: 1400);
 
-/// Pulsing title-bar chip when a background update check finds a newer release.
+/// How many [kUpdateBadgePulsePeriod] legs the chip pulses for when it appears
+/// (forward and back count as one leg each, so 6 is three full breaths), after
+/// which it settles to the static chip colors. An endless pulse keeps the
+/// engine producing a frame at the display rate and costs an idle app ~30% of
+/// a CPU core (#1554).
+const int kUpdateBadgePulseLegs = 6;
+
+/// Title-bar chip that pulses a few times when a background update check finds a newer release.
 class UpdateAvailableBadge extends material.StatefulWidget {
   const UpdateAvailableBadge({super.key, required this.controller});
 
@@ -30,6 +37,10 @@ class UpdateAvailableBadgeState extends material.State<UpdateAvailableBadge>
     with material.SingleTickerProviderStateMixin {
   late final material.AnimationController _pulse;
 
+  /// The finite pulse already ran for the update that is pending now; it is
+  /// cleared when the badge goes away so the next update pulses again.
+  bool _pulsed = false;
+
   @visibleForTesting
   bool get isPulseAnimating => _pulse.isAnimating;
 
@@ -77,6 +88,7 @@ class UpdateAvailableBadgeState extends material.State<UpdateAvailableBadge>
         _pulse.stop();
       }
       _pulse.value = 0;
+      if (!show) _pulsed = false;
       return;
     }
 
@@ -86,8 +98,18 @@ class UpdateAvailableBadgeState extends material.State<UpdateAvailableBadge>
     if (periodChanged) {
       _pulse.duration = period;
     }
-    if (!_pulse.isAnimating || periodChanged) {
-      _pulse.repeat(reverse: true);
+    final running = _pulse.isAnimating;
+    if (_pulsed && !running) return; // settled: stay static, stay idle
+
+    if (!running || periodChanged) {
+      _pulsed = true;
+      unawaited(
+        _pulse
+            .repeat(reverse: true, count: kUpdateBadgePulseLegs)
+            .whenComplete(() {
+          if (mounted) _pulse.value = 0;
+        }),
+      );
     }
   }
 

test/features/updater/update_available_badge_test.dart

@@ -121,4 +121,53 @@ void main() {
       Duration(microseconds: kUpdateBadgePulsePeriod.inMicroseconds ~/ 2),
     );
   });
+
+  testWidgets('pulse is finite: settles and stays idle (#1554)',
+      (tester) async {
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: QueryaMotionScope(
+          level: QueryaMotionLevel.full,
+          child: material.Scaffold(
+            body: UpdateAvailableBadge(controller: controller),
+          ),
+        ),
+      ),
+    );
+    await tester.pump();
+
+    const manifest = UpdateManifest(
+      version: '3.0.0',
+      changelog: '',
+      assets: [],
+    );
+    controller.setPendingUpdate(manifest);
+    await tester.pump();
+
+    final state = tester.state<UpdateAvailableBadgeState>(
+      find.byType(UpdateAvailableBadge),
+    );
+    expect(state.isPulseAnimating, isTrue);
+
+    await tester.pump(
+      kUpdateBadgePulsePeriod * kUpdateBadgePulseLegs +
+          const Duration(milliseconds: 100),
+    );
+    await tester.pump();
+    expect(state.isPulseAnimating, isFalse);
+    expect(find.textContaining('v3.0.0 available'), findsOneWidget);
+
+    // Another sync (controller notification, dependency change) must not
+    // start the pulse again for the same pending update.
+    controller.setPendingUpdate(manifest);
+    await tester.pump();
+    expect(state.isPulseAnimating, isFalse);
+
+    // A later update pulses again once the badge went away in between.
+    controller.setPendingUpdate(null);
+    await tester.pump();
+    controller.setPendingUpdate(manifest);
+    await tester.pump();
+    expect(state.isPulseAnimating, isTrue);
+  });
 }