angular / angular/components

bug(Tabs): ExpressionChangedAfterItHasBeenCheckedError when providing MatTabNavPanel to tabPanel input of mat-tab-nav-bar

Aperta
#28,379 4 commenti 5 reazioni 0 assegnatari Vedi su GitHub
area: material/tabs P4
Lingua principale
TypeScript
Stelle
25k
Fork
6.8k
Merge medio
1g 8h
PR unite (30g)
91

Descrizione

### Is this a regression?

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

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

Angular Material pre-MDC

### Description

mat-tab-nav-bar requires a reference to it's MatTabNavPanel via the tabPanel input. Documentation says this is optional but code makes it required as reported in https://github.com/angular/components/issues/26270.

However, when the mat-tab-nav-bar is wrapped in some other component, e.g. an AppHeaderComponent, but the MatTabNavPanel is outside this component, we need to pass the reference to the MatTabNavPanel via Input into the wrapper component like AppHeaderComponent and then use it in the template. This is the only way I can think of, but it throws a ExpressionChangedAfterItHasBeenCheckedError (quite obvious for everyone who understand Angular's CD resolution algorithm really good, but hard to understand for everyone else), for example

> ERROR Error: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value for 'attr.aria-labelledby': 'mat-tab-link-4'. Current value: 'mat-tab-link-2'. Expression location: TabNavBarBasicExample component.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/udrwuw?file=src%2Fexample%2Ftab-nav-bar-basic-example.html
Steps to reproduce:
1. Open developer console in browser
2. Click around on the Nav Items
3. Observe error in developer console

### Expected Behavior

No error. I suggest simply making tabPanel optional like stated in Documentation, but of course would be nice to have a good solution to use mat-tab-nav-bar in a wrapper component

### Actual Behavior

ExpressionChangedAfterItHasBeenCheckedError

### Environment

- Angular: 16+
- CDK/Material: 16+ aka MDC
- Browser(s): any
- Operating System (e.g. Windows, macOS, Ubuntu): any

Guida per i contributori

Apri la guida per i contributori

Direzione di ricerca

Inizia con la riproduzione StackBlitz, in particolare con src/example/tab-nav-bar-basic-example.html e il componente TabNavBarBasicExample, poi esamina come MatTabNavPanel viene passato attraverso il wrapper. Riproduci l'errore facendo clic sugli elementi di navigazione e confronta il comportamento con l'input tabPanel opzionale documentato; è completato quando l'errore nella console non si verifica più.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
angular, typescript
Ambito
frontend
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Ferma
Chiarezza
Abbastanza chiara
Idoneità per principianti
35/100

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