[Bug]: sbbAutocompleteTrigger writeValue is asynchronous

[daniel-sc]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for an issue that matches the one I want to file, without success.

Bug type

Functionality

Which version are you using

18.5.0

Operating system

Win11

Browser / Browser version

Firefox 131.0.3 (64-bit)

Input mode

None

Additional settings

No response

What happened?

When invoking writeValue (explicitly or implicitly via FormControl.setValue) on an input which has a autocomplete attached, the value is not synchronously applied to the HTMLInputElement.value, but only on the next tick.

This breaks the (implicit) contract, that the value should be reflected synchronously in the native elements value.

Relevant code:

sbb-angular/src/angular/autocomplete/autocomplete-trigger.ts

Line 494 in fbce1d5

Promise.resolve(null).then(() => this._assignOptionValue(value));

See as well: angular/components#3250

Steps to reproduce the issue

1. Invoke FormControl.setValue('a') on a FormControl bound to an input with autocomplete
2. Observe: input.nativeElement.value is not 'a' (which would be expected)

Relevant log output

No response

[kyubisation]

Our autocomplete implementation is adapted from the Material implementation (angular/components), which uses this approach as well. My assumption is that this is a limitation with the potentially changing sbb-option instances.
I'm not sure we can fix that.

[mhaertwig]

angular/components#3250