Re: [PATCH login-manager v3 5/5] fix #4281: ui: fix stale Continue button state on realm switch

["Shan Shaji" <s.shaji@proxmox.com>]

On Fri Aug 21, 2026 at 5:41 AM CEST, Azharul Haque wrote:
> Form(onChanged: ...) revalidates against whatever fields are
> currently mounted at the moment a FormField's own value changes.
> For the realm dropdown that runs before the following rebuild
> adds/removes the username/password fields for the newly selected
> realm's type, so Continue got enabled/disabled based on the
> outgoing realm's field set rather than the incoming one. Most
> visibly, switching from an OpenID realm to a password realm left
> Continue enabled with both fields empty, only failing validation
> once actually pressed.
>
> Recompute _submitButtonEnabled explicitly in onDomainChanged instead:
> OpenID realms have nothing to validate, so enable it directly; other
> realms are revalidated in a post-frame callback once the rebuild has
> settled. Do the same after the initial realm auto-selection in
> _getAccessDomains(), in case the default realm is an OpenID one.
>
> Signed-off-by: Azharul Haque <haque@azharul.com>
> ---
>  lib/proxmox_login_form.dart | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)

[snip]

> @@ -868,6 +893,9 @@ class _ProxmoxLoginPageState extends State<ProxmoxLoginPage> {
>      setState(() {
>        _progressModel.inProgress -= 1;
>        _selectedDomain = selection;
> +      // An OpenID realm has no username/password to fill in, so there's
> +      // nothing for the form to validate before Continue is usable.
> +      _submitButtonEnabled = selection?.isOpenIdRealm == true;

If I fill in the origin field and the SSL validation enabled, then press the
Continue button, the dialog is shown and the Continue button becomes
disabled. I have to edit the field again to re-enable the Continue button,
even though the form is valid.

That is, if selection is null, the button becomes disabled. As I understand
it, we also need to check whether selection is null before setting the
button state here:

```
  if (selection != null) {
    _submitButtonEnabled = selection!.isOpenIdRealm == true;
  }
```

Why use an if block instead of an inline check? Otherwise, the
submitButtonEnabled state variable is assigned false, which notifies the
framework that the object’s internal state has changed and needs to be
rebuilt. Because of this rebuild, the button becomes disabled.

>      });
>
>      return response;