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Getting '<Unexpected Null Value>' using with Flutter Web #300

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Getting '<Unexpected Null Value>' using with Flutter Web#300
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bugSomething isn't working
@jlubeck

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@jlubeck
jlubeck
opened on May 22, 2020

Just by using this simple script:

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

class TestScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Html(
        data: '<p>Test</p>',
      ),
    );
  }
}

And trying it on web I get the following error:

══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
The following NoSuchMethodError was thrown during performLayout():
'<Unexpected Null Value>'
method not found
Receiver: null
Arguments: []

The relevant error-causing widget was:
  Text
  file:///Users/jan/.pub-cache/hosted/pub.dartlang.org/flutter_html-1.0.0/lib/html_parser.dart:719:19

When the exception was thrown, this was the stack:
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 216:49      throw_
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 58:3        throwNullValueError
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 488:39  _notNull
packages/flutter/src/widgets/widget_span.dart 108:37                              build
packages/flutter/src/painting/text_span.dart 211:14                               build
packages/flutter/src/painting/text_span.dart 211:14                               build
packages/flutter/src/painting/text_painter.dart 558:13                            layout
packages/flutter/src/rendering/paragraph.dart 490:18                              [_layoutText]
packages/flutter/src/rendering/paragraph.dart 513:5                               [_layoutTextWithConstraints]
packages/flutter/src/rendering/paragraph.dart 581:5                               performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 266:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/shifted_box.dart 394:13                            performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/shifted_box.dart 207:11                            performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/paragraph.dart 530:12                              [_layoutChildren]
packages/flutter/src/rendering/paragraph.dart 580:5                               performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 266:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/shifted_box.dart 394:13                            performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/paragraph.dart 530:12                              [_layoutChildren]
packages/flutter/src/rendering/paragraph.dart 580:5                               performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 266:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 266:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/custom_layout.dart 171:10                          layoutChild
packages/flutter/src/material/scaffold.dart 480:7                                 performLayout
packages/flutter/src/rendering/custom_layout.dart 240:7                           [_callPerformLayout]
packages/flutter/src/rendering/custom_layout.dart 399:14                          performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/proxy_box.dart 1265:11                             performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/proxy_box.dart 3242:13                             performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/widgets/overlay.dart 700:14                                  performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/proxy_box.dart 111:13                              performLayout
packages/flutter/src/rendering/object.dart 1767:7                                 layout
packages/flutter/src/rendering/view.dart 167:48                                   performLayout
packages/flutter/src/rendering/object.dart 1630:7                                 [_layoutWithoutResize]
packages/flutter/src/rendering/object.dart 887:17                                 flushLayout
packages/flutter/src/rendering/binding.dart 402:19                                drawFrame
packages/flutter/src/widgets/binding.dart 865:13                                  drawFrame
packages/flutter/src/rendering/binding.dart 284:5                                 [_handlePersistentFrameCallback]
packages/flutter/src/scheduler/binding.dart 1074:15                               [_invokeFrameCallback]
packages/flutter/src/scheduler/binding.dart 1013:9                                handleDrawFrame
packages/flutter/src/scheduler/binding.dart 822:7                                 <fn>
dart-sdk/lib/_internal/js_dev_runtime/private/isolate_helper.dart 50:19           internalCallback

The following RenderObject was being processed when the exception was fired: RenderParagraph#ab787 relayoutBoundary=up12 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE:
  creator: RichText ← Text ← SizedBox ← StyledText ← Align ← DecoratedBox ← Padding ← Container ←
    ContainerSpan ← RichText ← Text ← SizedBox ← ⋯
  parentData: <none> (can use size)
  constraints: BoxConstraints(w=1645.0, 0.0<=h<=Infinity)
  size: MISSING
  textAlign: start
  textDirection: ltr
  softWrap: wrapping at box width
  overflow: clip
  locale: en_US
  maxLines: unlimited
This RenderObject had the following descendants (showing up to depth 5):
    text: TextSpan
      TextSpan
        WidgetSpan#ec776
════════════════════════════════════════════════════════════════════════════════════════════════════
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: NoSuchMethodError: '<Unexpected Null Value>'

This is my flutter doctor

[✓] Flutter (Channel beta, 1.18.0-11.1.pre, on Mac OS X 10.15.4 19E287, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 11.5)
[✓] Chrome - develop for the web
[✓] Android Studio (version 3.6)
[!] VS Code (version 1.45.1)
    ✗ Flutter extension not installed; install from
      https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter
[✓] Connected device (3 available)

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