regression: signal forms: input of type date isn't required anymore when cleared #67300
Description
Which @angular/* package(s) are the source of the bug?
forms
Is this a regression?
Yes
Description
Since version 21.2.0, an input of type date in a signal form, when the user erases its day, month or year, keeps its value instead of becoming empty, and becomes invalid with a parse error.
Please provide a link to a minimal reproduction of the bug
Please provide the exception or error you saw
When populating the birth date field and then erasing one or even all of its components (day, month or year), I expect the value to become empty again (or better: null, like when a number input is erased), and the required error to reappear. Instead, the value stays as it was before, the field becomes invalid, with a parse error.
Please provide the environment you discovered this bug in (run ng version)
Angular CLI : 21.1.5
Angular : 21.2.0
Node.js : 20.19.1
Package Manager : pnpm 8.15.6
Operating System : linux x64
┌───────────────────────────┬───────────────────┬───────────────────┐
│ Package │ Installed Version │ Requested Version │
├───────────────────────────┼───────────────────┼───────────────────┤
│ @angular/build │ 21.1.5 │ ^21.1.5 │
│ @angular/cli │ 21.1.5 │ ^21.1.5 │
│ @angular/common │ 21.2.0 │ 21.2.0 │
│ @angular/compiler │ 21.2.0 │ 21.2.0 │
│ @angular/compiler-cli │ 21.2.0 │ 21.2.0 │
│ @angular/core │ 21.2.0 │ 21.2.0 │
│ @angular/forms │ 21.2.0 │ 21.2.0 │
│ @angular/platform-browser │ 21.2.0 │ 21.2.0 │
│ @angular/router │ 21.2.0 │ 21.2.0 │
│ rxjs │ 7.8.2 │ ^7.8.1 │
│ typescript │ 5.9.3 │ ^5.9.3 │
└───────────────────────────┴───────────────────┴───────────────────┘
Anything else?
Sorry for the edits on this issue. I intially thought there was no error at all, but that was because I tried to display the errors using the JSON pipe, which threw an error because parse errors are apparently not serializable to JSON. That could be a separate issue: it would be nice for errors to be serializable to JSON, at least to ease debugging.