firka/flutter
firka/flutter
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Assert that the widget is the T in State<T>

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Mostly because we can, but hopefully it'll catch someone who
accidentally copypasted their createState method.
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Hixie 2015-10-01 13:20:47 -07:00
parent fbd5460b04
commit 834165448b
1 changed files with 5 additions and 0 deletions
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5
packages/flutter/lib/src/widgets/framework.dart
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@ -293,6 +293,10 @@ abstract class State<T extends StatefulComponent> {
/// This is used to verify that State objects move through life in an orderly fashion. /// This is used to verify that State objects move through life in an orderly fashion.
_StateLifecycle _debugLifecycleState = _StateLifecycle.created; _StateLifecycle _debugLifecycleState = _StateLifecycle.created;
/// Verifies that the State that was created is one that expects to be created
/// for that particular Widget.
bool _debugTypesAreRight(widget) => widget is T;
/// Pointer to the owner Element object /// Pointer to the owner Element object
StatefulComponentElement _element; StatefulComponentElement _element;
@ -825,6 +829,7 @@ class StatelessComponentElement<T extends StatelessComponent> extends BuildableE
class StatefulComponentElement extends BuildableElement<StatefulComponent> { class StatefulComponentElement extends BuildableElement<StatefulComponent> {
StatefulComponentElement(StatefulComponent widget) StatefulComponentElement(StatefulComponent widget)
: _state = widget.createState(), super(widget) { : _state = widget.createState(), super(widget) {
assert(_state._debugTypesAreRight(widget));
assert(_state._element == null); assert(_state._element == null);
_state._element = this; _state._element = this;
assert(_builder == null); assert(_builder == null);