Submitting a form during an ajax request: field data not in $_POST.

Reroll against 10.1.x

#49 called for issue summary update which believe still needs to happen.

Fixed, CCF in #55. Attached interdiff for same. leaving as NW, as issue summary still needs to update.

I updated the IS and title based on the discussion to date and my assessment of the issue. The summary of my summary is: there isn’t sufficient support for the original proposed solution as a core fix, but there is overall support and arguments in favor of disabling the submit button.

I agree with #34 that there are 2 separate issues here.

I think that submit should be disabled so that the form can’t be submitted while the ajax change call is running and before the server has responded. If you're going all the way to the server for a change event, it's probably important that it finishes and, if that's the case, the submit button should be disabled until the form is ready to be interacted with again. Since the ajax change call response can modify the values in the form, the user should not be able to submit the form with just the values they provided in the field (e.g., entity reference fields that rely on ajax change events).

However, I don’t think that disabling the submit button addresses the reported issue and, IMO, would unnecessarily expand the scope of this ticket.

The problem described here is that the change event isn’t triggered until the text field loses focus, which can cause data loss because a user can submit the form without losing focus on the field, but before ajax ever runs. In other words, the form gets submitted, but ajax was never triggered, so the value isn’t saved.

I think that further discussion should be around determining what type of event should be used to fire the ajax change.

Reroll of patch in #57 for 10.3.x

Patch #61 doesn't contain all newly added files.