Follow up to Backport [2346893] to Drupal 7.
Problem/Motivation
Duplicate AJAX wrappers are causing some errors to be rendered twice.
Symptoms have been reported around file field and image field.
In #115 @lauriii notes the element prefix and suffix are added in the twig template, as well as in the renderer.
Steps to replicate using the File field:
- Add a file field to basic page content type.
- Upload file of any type other than text.
- Double error is triggered.
Proposed resolution
Fix this at the source in the ajax rendering system, not just at the points where symptoms occur.
Patch at #176
@xjm notes the #render_children property is defined in core/lib/Drupal/Core/Render/Element/RenderElement.php
Remaining tasks
- Needs theme system maintainer review.
- Create a follow-up issue to backport this to D7.
- Fix templates in a non backwards compatible manner for D9.
- Resolve ongoing discussion of related changes to metadata.
- Decide whether or not to bubble up the cache and assets here. [See #185 ]
Example of a user interface change
Show error once, instead of twice! :-) This is just one example. There are likely other places that will be impacted by this change.
Before patch:
Patched:
API changes
When #render_children is set, everything inside render array except children will be ignored.
Data model changes
None.
Discussion Summary
@idimopoulas reports doing a manual review at #177
@Fabianx explains the problem clearly in #134 and provides a patch at #137
@joelpittet manual review with screenshots at #122
@swentel reports symptom is fixed for image fields but still occurring for file fields in #69
Original report
If I edit my profile, and upload a picture to Picture field, after that I see the messages but twice all times. (drupal_render() should check if it's rendering a 'render element' and if so call drupal_render_children() (inline) instead (1920886) ) not about the ajax its just rendering the element.
I find these message only one place (/core/modules/file/file.module;466) and I think somewhere is called twice. István Palócz see that bug, and he said the problem somewhere in ajax response.
