System Status Messages lose theming in core 10.3 with BigPipe enabled

Thank you for this topic because I encounter the same problem and I didn't understand because everything worked before.

Messages displayed with toast work in certain cases (for example when a user logs out) but it no longer works in a custom form if I do that for example.

\Drupal::messenger()->addStatus('Votre demande n\'a pas été enregistrée : ' . $test->reason);

If I disable BigPipe everything works.

This issue belongs and is reported on core

For me, the issue only occurs with some authenticated users. I've tried to narrow it down a bit based on permissions, but no luck.

Disabling BigPipe solves the issue for all users, so I'll be waiting for 🐛 10.3 upgrade now missing status-message theme suggestions Postponed to be resolved as well.

-mike

According to https://www.drupal.org/project/drupal/issues/3456176 🐛 10.3 upgrade now missing status-message theme suggestions Postponed this may be something that this theme needs to implement. So reopening the issue.

MessageCommand and the associated JavaScript API was added to Drupal core in 2019/Drupal 8.8.0, but was not used widely in Drupal core until 10.3.0, when the bigpipe module began using it to render messages created within bigpipe placeholders.

Because MessageCommand has not been used widely, many custom themes have not themed custom JavaScript messages.

For examples of how to override message theming, see:

core/themes/olivero/js/message.theme.js

and

core/themes/claro/js/messages.js

And the associated libraries-extend entries in those themes' .info.yml files.

Fixed on beta version

Proposed solution at https://www.drupal.org/project/drupal/issues/3456176#comment-15738200 🐛 10.3 upgrade now missing status-message theme suggestions Postponed fixed it for me.