custom form elements can't cleanly set a value for themselves

oh, but wait... I updated to 4.7.0-beta2 and #process *does* seem to be called when the form is submitted

if I have #process => array('fxn' => array())

and
fxn($element)
{
$element['#value'] = 'xyz';
return $element;
}

that #value doesn't seem to get passed along.

I'm gonna mark this as a bug, though I could be wrong about there being no way to do this.

The #process function gets called after global $form_values takes on the value in #value, so there's no way for it to affect the value without touching $form_values itself.

here's a module which helps explain what this bug is about, via an illustrative example.

1. Put the module in your modules directory
2. go to "admin/modules"
3. enable the "bug41023" module
4. go to "41023"
5. press "Go"

Expected behavior:
[a] is set to 'hi there'

Actual behavior:
[a] is not set

my sample code wasn't returning $element from the #process function. fixed that.

yes, i'm trying to compose those posted values into a uber-combined value.

I didn't put any children in the element because then I'd also need to add a theme function to the example code. Hold on while I expand the example a bit to make it clearer.

that's a good thing, since the new example was getting pretty hard to understand.

a point from the conversation with Károly

the patch shouldn't affect anything (Károly was initially concerned about it affecting previews) since all it does is move the assignment into $form_values from immediately before the #process call to immediately afterwards.