angular / angular/components

bug(checkbox): Tri-state checkbox runs out of sync with its input after a change event

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#27,150 0 commentaires 3 réactions 0 personnes assignées Voir sur GitHub
area: material/checkbox P3
Langage dominant
TypeScript
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Merge moyen
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Description

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

I think the direct implementation with the `(change)` checkbox output (represented in https://stackblitz.com/edit/angular-tzjh4u?file=src%2Fmain.ts) has never worked.

With the Legacy checkbox, we had a workaround that relied on `click` and `keyup.space` DOM events instead of relying on the component's `change` output.
After migrating to MDC, this workaround no longer works, too.

### Reproduction

https://stackblitz.com/edit/angular-tzjh4u?file=src%2Fmain.ts

Steps to reproduce:
1. Click checkbox to toggle between "checked" and "unchecked" - see how the checkbox state (checkmark) is always in sync with the app state (`this.state`)
2. Click the "Set to indeterminate" button
3. Click the checkbox, which is currently in the indeterminate state

### Expected Behavior

Checkbox becomes "unchecked"

### Actual Behavior

Checkbox becomes "checked", despite `this.state` is "unchecked". Checkbox is now out of sync with its input. Note how `ng-reflect-checked="false"`, while the classname includes `mat-mdc-checkbox-checked`

### Environment

- Angular 16.0.2
- CDK/Material: 16.0.1
- Browser(s): Firefox, Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): macOS

Guide de contribution

Ouvrir le guide de contribution

Piste de recherche

Commencez par la reproduction StackBlitz liée dans src/main.ts et reproduisez la transition de indeterminate à unchecked via l’événement change de la case à cocher. Suivez le comportement de la case à cocher à trois états et vérifiez que l’état visuel et l’état de l’input restent synchronisés après la modification.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Évaluation

Stack technique
angular, typescript
Domaine
frontend
Type d'issue
Bug
Difficulté
4/5
Temps estimé
3-5 jours
Activité
À l'abandon
Clarté
Plutôt claire
Accessibilité débutants
35/100

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