Dynamically generated pie chart with badges causes render exception.

[zhaozhixu]

Describe the bug
A dynamically generated pie chart with badges causes RangeError (length): Invalid value exception.

To Reproduce
Build a simple counter app with a PieChart widget which adds sections when clicking the counter button (counting from 1), and the exception shows in the console log.

import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 1;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(
              child: LayoutBuilder(
                builder: (context, constraints) {
                  return PieChart(
                    PieChartData(
                      sections: _buildChartSections(context, constraints),
                      sectionsSpace: 2,
                      centerSpaceRadius: 0,
                      pieTouchData: PieTouchData(touchCallback: (FlTouchEvent event, pieTouchResponse) {}),
                    ),
                  );
                },
              ),
            ),
            const Text('You have pushed the button this many times:'),
            Text('$_counter', style: Theme.of(context).textTheme.headlineMedium),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }

  List<PieChartSectionData> _buildChartSections(BuildContext context, BoxConstraints constraints) {
    double radius = constraints.maxHeight > constraints.maxWidth ? constraints.maxWidth : constraints.maxHeight;
    print("_buildChartSections: $_counter");

    return List.generate(_counter, (index) {
      final color = Color((DateTime.now().microsecondsSinceEpoch % 0xFFFFFF) | 0xFF000000);
      return PieChartSectionData(
        title: "$index",
        titleStyle: TextStyle(
          fontWeight: FontWeight.bold,
          color: const Color(0xffffffff),
        ),
        value: 10,
        color: color,
        radius: radius * 0.3,
        showTitle: true,
        badgeWidget: _BadgeWidget("$index", color, radius * 0.1),
        badgePositionPercentageOffset: .98,
      );
    });
  }
}

class _BadgeWidget extends StatelessWidget {
  final String txt;
  final Color color;
  final double radius;

  const _BadgeWidget(this.txt, this.color, this.radius);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: radius,
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surface,
        shape: BoxShape.circle,
        border: Border.all(color: color, width: 2),
      ),
      child: Center(
        child: Text(txt, style: TextStyle(color: color)),
      ),
    );
  }
}

Console output

Launching lib/main.dart on sdk gphone64 arm64 in debug mode...
Running Gradle task 'assembleDebug'...                              3.7s
✓ Built build/app/outputs/flutter-apk/app-debug.apk
Installing build/app/outputs/flutter-apk/app-debug.apk...          466ms
D/FlutterJNI(19685): Beginning load of flutter...
D/FlutterJNI(19685): flutter (null) was loaded normally!
I/flutter (19685): [IMPORTANT:flutter/shell/platform/android/android_context_gl_impeller.cc(104)] Using the Impeller rendering backend (OpenGLES).
Syncing files to device sdk gphone64 arm64...                       21ms

Flutter run key commands.
r Hot reload. 🔥🔥🔥
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).

A Dart VM Service on sdk gphone64 arm64 is available at: http://127.0.0.1:53282/6UBWvL27vP8=/
I/flutter (19685): _buildChartSections: 1
The Flutter DevTools debugger and profiler on sdk gphone64 arm64 is available at: http://127.0.0.1:9101?uri=http://127.0.0.1:53282/6UBWvL27vP8=/
I/WindowExtensionsImpl(19685): Initializing Window Extensions, vendor API level=6, activity embedding enabled=true
W/HWUI    (19685): Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
W/HWUI    (19685): Failed to initialize 101010-2 format, error = EGL_SUCCESS
I/Gralloc4(19685): mapper 4.x is not supported
I/flutter (19685): _buildChartSections: 1
I/.test_pie_chart(19685): Compiler allocated 5250KB to compile void android.view.ViewRootImpl.performTraversals()
I/flutter (19685): _buildChartSections: 2

══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
The following RangeError was thrown during paint():
RangeError (length): Invalid value: Only valid value is 0: 1

The relevant error-causing widget was:
  PieChartLeaf
  PieChartLeaf:file:///Users/zhixu/.pub-cache/hosted/pub.dev/fl_chart-1.1.1/lib/src/chart/pie_chart/pie_chart.dart:57:12

When the exception was thrown, this was the stack:
#0      List.[] (dart:core-patch/growable_array.dart)
#1      RenderPieChart.badgeWidgetPaint (package:fl_chart/src/chart/pie_chart/pie_chart_renderer.dart:154:24)
#2      RenderPieChart.paint (package:fl_chart/src/chart/pie_chart/pie_chart_renderer.dart:146:5)
#3      RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#4      PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#5      _RenderLayoutBuilder.paint (package:flutter/src/widgets/layout_builder.dart:471:15)
#6      RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#7      PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#8      RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:3367:15)
#9      RenderFlex.paint (package:flutter/src/rendering/flex.dart:1317:7)
#10     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#11     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#12     RenderShiftedBox.paint (package:flutter/src/rendering/shifted_box.dart:81:15)
#13     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#14     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#15     RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:3367:15)
#16     RenderCustomMultiChildLayoutBox.paint (package:flutter/src/rendering/custom_layout.dart:425:5)
#17     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#18     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#19     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:140:13)
#20     _RenderInkFeatures.paint (package:flutter/src/material/material.dart:634:11)
#21     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#22     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#23     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:140:13)
#24     RenderPhysicalModel.paint.<anonymous closure> (package:flutter/src/rendering/proxy_box.dart:2184:15)
#25     PaintingContext.pushClipRRect (package:flutter/src/rendering/object.dart:609:14)
#26     RenderPhysicalModel.paint (package:flutter/src/rendering/proxy_box.dart:2171:21)
#27     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#28     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#29     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:140:13)
#30     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#31     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:261:13)
#32     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:140:13)
#33     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3423:7)
#34     PaintingContext._repaintCompositedChild (package:flutter/src/rendering/object.dart:176:11)
#35     PaintingContext.repaintCompositedChild (package:flutter/src/rendering/object.dart:121:5)
#36     PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:1309:31)
#37     PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:1319:15)
#38     RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:631:23)
#39     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:1261:13)
#40     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:495:5)
#41     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1434:15)
#42     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1347:9)
#43     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:1200:5)
#44     _invoke (dart:ui/hooks.dart:330:13)
#45     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:444:5)
#46     _drawFrame (dart:ui/hooks.dart:302:31)

The following RenderObject was being processed when the exception was fired: RenderPieChart#2195c relayoutBoundary=up4:
  creator: PieChartLeaf ← PieChart ← LayoutBuilder ← Expanded ← Column ← Center ←
    KeyedSubtree-[GlobalKey#82df0] ← _BodyBuilder ← MediaQuery ← LayoutId-[<_ScaffoldSlot.body>] ←
    CustomMultiChildLayout ← _ActionsScope ← ⋯
  parentData: offset=Offset(0.0, 0.0) (can use size)
  constraints: BoxConstraints(0.0<=w<=411.4, h=778.3)
  size: Size(411.4, 778.3)
This RenderObject had the following descendants (showing up to depth 5):
    child 1: RenderConstrainedBox#d4bfa relayoutBoundary=up5
      child: RenderDecoratedBox#933ec relayoutBoundary=up6
        child: RenderPadding#c000a relayoutBoundary=up7
          child: RenderPositionedBox#6aba5 relayoutBoundary=up8
            child: RenderParagraph#e98c4 relayoutBoundary=up9
    child 2: RenderConstrainedBox#d06a6 NEEDS-LAYOUT NEEDS-PAINT
      child: RenderDecoratedBox#0e69a NEEDS-LAYOUT NEEDS-PAINT
        child: RenderPadding#f2c2f NEEDS-LAYOUT NEEDS-PAINT
          child: RenderPositionedBox#d83d8 NEEDS-LAYOUT NEEDS-PAINT
            child: RenderParagraph#27aa9 NEEDS-LAYOUT NEEDS-PAINT
════════════════════════════════════════════════════════════════════════════════════════════════════

Versions

• which version of the Flutter are you using? 3.35.7
• which version of the FlChart are you using? 1.1.1