Cheaper debug string for widget-provided tickers (#81247)

packages/flutter/lib/src/widgets/ticker_provider.dart

@@ -126,7 +126,7 @@ mixin SingleTickerProviderStateMixin<T extends StatefulWidget> on State<T> imple
         ),
       ]);
     }());
-    _ticker = Ticker(onTick, debugLabel: kDebugMode ? 'created by $this' : null);
+    _ticker = Ticker(onTick, debugLabel: kDebugMode ? 'created by ${describeIdentity(this)}' : null);
     // We assume that this is called from initState, build, or some sort of
     // event handler, and that thus TickerMode.of(context) would return true. We
     // can't actually check that here because if we're in initState then we're
@@ -199,7 +199,7 @@ mixin TickerProviderStateMixin<T extends StatefulWidget> on State<T> implements
   @override
   Ticker createTicker(TickerCallback onTick) {
     _tickers ??= <_WidgetTicker>{};
-    final _WidgetTicker result = _WidgetTicker(onTick, this, debugLabel: 'created by $this');
+    final _WidgetTicker result = _WidgetTicker(onTick, this, debugLabel: kDebugMode ? 'created by ${describeIdentity(this)}' : null);
     _tickers!.add(result);
     return result;
   }

packages/flutter/test/widgets/ticker_provider_test.dart

@@ -117,7 +117,7 @@ void main() {
           'the ticker will leak.\n'
         );
         expect(error.diagnostics[3], isA<DiagnosticsProperty<Ticker>>());
-        expect(error.toStringDeep().split('\n').take(14).join('\n'), equalsIgnoringHashCodes(
+        expect(error.toStringDeep().split('\n').take(13).join('\n'), equalsIgnoringHashCodes(
           'FlutterError\n'
             '   _SingleTickerTestState#00000(ticker active) was disposed with an\n'
             '   active Ticker.\n'
@@ -129,8 +129,7 @@ void main() {
             '   calling dispose() on the AnimationController itself. Otherwise,\n'
             '   the ticker will leak.\n'
             '   The offending ticker was:\n'
-            '     Ticker(created by _SingleTickerTestState#00000(lifecycle state:\n'
+            '     Ticker(created by _SingleTickerTestState#00000)\n'
-            '     created))\n'
             '     The stack trace when the Ticker was actually created was:'
         ));
         key.currentState!.controller.stop();
@@ -158,7 +157,7 @@ void main() {
           'the ticker will leak.\n'
         );
         expect(error.diagnostics[3], isA<DiagnosticsProperty<Ticker>>());
-        expect(error.toStringDeep().split('\n').take(14).join('\n'), equalsIgnoringHashCodes(
+        expect(error.toStringDeep().split('\n').take(13).join('\n'), equalsIgnoringHashCodes(
           'FlutterError\n'
           '   _SingleTickerTestState#00000(ticker active) was disposed with an\n'
           '   active Ticker.\n'
@@ -170,15 +169,14 @@ void main() {
           '   calling dispose() on the AnimationController itself. Otherwise,\n'
           '   the ticker will leak.\n'
           '   The offending ticker was:\n'
-          '     Ticker(created by _SingleTickerTestState#00000(lifecycle state:\n'
+          '     Ticker(created by _SingleTickerTestState#00000)\n'
-          '     created))\n'
           '     The stack trace when the Ticker was actually created was:'
         ));
         key.currentState!.controller.stop();
       }
     });
 
-    testWidgets('ProviderStateMixin dispose while any ticker is active', (WidgetTester tester) async {
+    testWidgets('TickerProviderStateMixin dispose while any ticker is active', (WidgetTester tester) async {
       final GlobalKey<_MultipleTickerTestState> key = GlobalKey<_MultipleTickerTestState>();
       final Widget widget = _MultipleTickerTest(key: key);
       await tester.pumpWidget(widget);
@@ -199,7 +197,7 @@ void main() {
           'the ticker will leak.\n'
         );
         expect(error.diagnostics[3], isA<DiagnosticsProperty<Ticker>>());
-        expect(error.toStringDeep().split('\n').take(14).join('\n'), equalsIgnoringHashCodes(
+        expect(error.toStringDeep().split('\n').take(12).join('\n'), equalsIgnoringHashCodes(
           'FlutterError\n'
           '   _MultipleTickerTestState#00000(tickers: tracking 2 tickers) was\n'
           '   disposed with an active Ticker.\n'
@@ -211,14 +209,22 @@ void main() {
           '   calling dispose() on the AnimationController itself. Otherwise,\n'
           '   the ticker will leak.\n'
           '   The offending ticker was:\n'
-          '     _WidgetTicker(created by\n'
+          '     _WidgetTicker(created by _MultipleTickerTestState#00000)'
-          '     _MultipleTickerTestState#00000(lifecycle state: created,\n'
-          '     tickers: tracking 0 tickers))'
         ));
         key.currentState!.controllers.first.stop();
       }
     });
   });
+
+  testWidgets('SingleTickerProviderStateMixin does not call State.toString', (WidgetTester tester) async {
+    await tester.pumpWidget(const _SingleTickerTest());
+    expect(tester.state<_SingleTickerTestState>(find.byType(_SingleTickerTest)).toStringCount, 0);
+  });
+
+  testWidgets('TickerProviderStateMixin does not call State.toString', (WidgetTester tester) async {
+    await tester.pumpWidget(const _MultipleTickerTest());
+    expect(tester.state<_MultipleTickerTestState>(find.byType(_MultipleTickerTest)).toStringCount, 0);
+  });
 }
 
 class BoringTickerTest extends StatefulWidget {
@@ -255,6 +261,14 @@ class _SingleTickerTestState extends State<_SingleTickerTest> with SingleTickerP
   Widget build(BuildContext context) {
     return Container();
   }
+
+  int toStringCount = 0;
+
+  @override
+  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) {
+    toStringCount += 1;
+    return super.toString(minLevel: minLevel);
+  }
 }
 
 class _MultipleTickerTest extends StatefulWidget {
@@ -279,6 +293,14 @@ class _MultipleTickerTestState extends State<_MultipleTickerTest> with TickerPro
   Widget build(BuildContext context) {
     return Container();
   }
+
+  int toStringCount = 0;
+
+  @override
+  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) {
+    toStringCount += 1;
+    return super.toString(minLevel: minLevel);
+  }
 }
 
 class _SingleTickerCreateMultipleTicker extends StatefulWidget {