Convert theme_radios() to Twig

Working on this one...

Let's see...

Tested on a two field instances (list and boolean). The markup before and after applying the patch (in #3) was identical. See attached screenshots, with twig debug code in the 'after' shots.

Scenario for profiling
1. login as admin
2. select structure; contact form categories
3. select website feedback, click edit
4. go to manage fields
5. add new field
label: some check boxes
field type: list (integer)
6. click on save
7. enter that user must select at least 2 options
list of options:
10|check me 10
11|check me 11
12|check me 12
13|check me 13
14|check me 14
8. Save; go to manage display. select "checkboxes/radio" for display
9. now add another field
label: some radio buttons
field type: list (integer)
10. click on save
11. enter that user must select just 1 option
list of options:
1|check me 1
2|check me 2
3|check me 3
4|check me 4
5|check me 5
12. Save; go to manage display. select "checkboxes/radio" for display
13. go to system settings and enter as default page: /contact
14. now open site, contact form with checkboxes and radio buttons will be displayed.
15. now is good moment to backup database since it can be used again later for radio buttons

<!-- THEME DEBUG -->
<!-- CALL: theme('radios') -->
<!-- BEGIN OUTPUT from 'core/modules/system/templates/radios.html.twig' -->
<div aria-describedby="edit-field-some-radio-buttons--description" id="edit-field-some-radio-buttons" class="form-radios"><div class="form-item form-type-radio form-item-field-some-radio-buttons">
 <input aria-describedby="edit-field-some-radio-buttons--description" type="radio" id="edit-field-some-radio-buttons-1" name="field_some_radio_buttons" value="1" class="form-radio" /> <label class="option" for="edit-field-some-radio-buttons-1">option 1</label>
</div>
<div class="form-item form-type-radio form-item-field-some-radio-buttons">
 <input aria-describedby="edit-field-some-radio-buttons--description" type="radio" id="edit-field-some-radio-buttons-2" name="field_some_radio_buttons" value="2" class="form-radio" /> <label class="option" for="edit-field-some-radio-buttons-2">option 2</label>
</div>
<div class="form-item form-type-radio form-item-field-some-radio-buttons">
 <input aria-describedby="edit-field-some-radio-buttons--description" type="radio" id="edit-field-some-radio-buttons-3" name="field_some_radio_buttons" value="3" class="form-radio" /> <label class="option" for="edit-field-some-radio-buttons-3">option 3</label>
</div>
<div class="form-item form-type-radio form-item-field-some-radio-buttons">
 <input aria-describedby="edit-field-some-radio-buttons--description" type="radio" id="edit-field-some-radio-buttons-4" name="field_some_radio_buttons" value="4" class="form-radio" /> <label class="option" for="edit-field-some-radio-buttons-4">option 4</label>
</div>
</div>

<!-- END OUTPUT from 'core/modules/system/templates/radios.html.twig' -->

Profiling test results:
Run 52e4a1c03557c uploaded successfully for drupal-perf-drupalcon.
Run 52e4a1fd8a982 uploaded successfully for drupal-perf-drupalcon.

=== 8.x..8.x compared (52e4a1c03557c..52e4a1fd8a982):

ct  : 38,893|38,893|0|0.0%
wt  : 159,364|158,964|-400|-0.3%
cpu : 148,493|148,120|-373|-0.3%
mu  : 14,562,696|14,562,696|0|0.0%
pmu : 14,669,600|14,669,600|0|0.0%

http://www.lionsad.de/xhprof-kit/xhprof/xhprof_html/?run1=52e4a1c03557c&...

Run 52e4a1c03557c uploaded successfully for drupal-perf-drupalcon.
Run 52e4a222581ef uploaded successfully for drupal-perf-drupalcon.

=== 8.x..2152221-3-radio-twig compared (52e4a1c03557c..52e4a222581ef):

ct  : 38,893|38,984|91|0.2%
wt  : 159,364|159,857|493|0.3%
cpu : 148,493|148,705|212|0.1%
mu  : 14,562,696|14,588,408|25,712|0.2%
pmu : 14,669,600|14,696,032|26,432|0.2%

http://www.lionsad.de/xhprof-kit/xhprof/xhprof_html/?run1=52e4a1c03557c&...

Fixed comments standards.

+++ b/core/includes/form.inc
@@ -1071,7 +1071,7 @@
+  $variables['children'] = isset($element['#children']) ? $element['#children'] : '';

isset() is not nessasary, i't always initialized in drupal_render()

And the reason it's failing is because the twig template was dropped in patch #10

1. Re-added the dropped template and rolled back the change identified in comment 13.
2. Removed extra line in comment for function form_pre_render_radio().
3. Created interdiff from patch in comment 3.

Could you tackle this change too?
+ $variables['children'] = isset($element['#children']) ? $element['#children'] : '';
to
+ $variables['children'] = $element['#children'];

Of course!

Sorry, misunderstood the comment before.

1. +++ b/core/includes/form.inc
   @@ -1037,30 +1037,33 @@ function form_pre_render_radio($element) {
   -  $attributes = array();
   ...
   +  // Remove the disabled attibute on the wrapper.
   +  unset($variables['attributes']['disabled']);
   

   Just a note, these two lines are doing essentially the same thing.

2. +++ b/core/includes/form.inc
   @@ -1037,30 +1037,33 @@ function form_pre_render_radio($element) {
   +  $variables['attributes']['class'] = array();
   

   This line is clobbering any css class that gets passed through

3. +++ b/core/includes/form.inc
   @@ -1037,30 +1037,33 @@ function form_pre_render_radio($element) {
   +  $variables['attributes']['class'][] = 'form-radios';
      if (!empty($element['#attributes']['class'])) {
   -    $attributes['class'] .= ' ' . implode(' ', $element['#attributes']['class']);
   +    $variables['attributes']['class'] = array_merge($variables['attributes']['class'], $element['#attributes']['class']);
      }
   

   So saying that, we might as well remove the array_merge, which is a heavy function call to merge on one class. Do the $element['#attributes']['class'] assignment and add form-radios.

4. +++ b/core/modules/system/templates/radios.html.twig
   @@ -0,0 +1,17 @@
   + */
   + @todo: remove this file once http://drupal.org/node/1819284 is resolved.
   + This is identical to core/modules/system/templates/container.html.twig
   

   Remove the @todo, we'll take care of that when we do consolidation.

Took care of items in #18 and re-thought them a bit. I left the clobbering $attributes = array() and remove the unset, that's not something we need to deal with in this issue.

19: 2152221-twig-theme_radios-19.patch queued for re-testing.

19: 2152221-twig-theme_radios-19.patch queued for re-testing.

It works fine for me.

I've uploaded a screenshot.

This looks identical to before, so success! RTBC++

Before:

After:

Committed and pushed to 8.x. Thanks!

Sorry, I messed up the commit credit on this one the first time. Good to know that the "commit-back" comments handle reverts, too. :)