Clean up the way attributes are printed in field.html.twig

I think what's being proposed makes sense. The patch applies cleanly also.
I do see that in the case of the node title field ends up weird. I went and tried to understand what the heck is going on, but failed misserably. This is over my head so I cant help out more other than testing =)

Rerolled the patch #10

Fixed the failing tests

If testbot says "green" then it's a RTBC.

I tried to add a few extra attributes and it seems to be working for some fields and taxonomy term fields, also for fields in comments.

1. +++ b/core/modules/system/templates/field.html.twig
   @@ -34,8 +35,8 @@
   +      <div class="field-item"{{ item.attributes }}>{{ item.value }}</div>
   
   +++ b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
   @@ -22,7 +23,7 @@
   +      <li class="taxonomy-term-reference-{{ delta }}"{{ item.attributes }}>{{ item.value }}</li>
   

   What happens if someone adds a class - this looks fragile should it be something like <div class="field-item{% if item.attributes.class %} {{ item.attributes.class }}{% endif %}"{{ item.attributes|without('class') }}>

2. +++ b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
   @@ -22,7 +23,7 @@
        {% for delta, item in items %}
   

   Shouldn't this be {% for item in items %}?

I fixed point 1. by using addClass(). Shouldn't we have delta there for the class name?

Removed the 'taxonomy-term-reference-' ~ delta class because its not used in core anywhere.

+++ b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
@@ -9,20 +9,21 @@
     {% for delta, item in items %}
-      <li class="taxonomy-term-reference-{{ delta }}"{{ item_attributes[delta] }}>{{ item }}</li>
+      <li{{ item.attributes }}>{{ item.value }}</li>
     {% endfor %}

Now we don't need the delta :)

Fix'd :)

Putting back to rtbc

What about trying something like this.

There was some changes in the line numbers since lauriii's patch, those are visible in the interdiff. My changes affect only field.html.twig, field--taxonomy-term-reference.html.twig and theme.inc.

Sending to testbot.

Changed 'attributes' to '#attributes' in comment.module.

Only thing changed between 28 and 39 is that 'attributes' is now '#attributes' which we are forced to do. More discussion about same kind of issue here: #2329919: Move views_ui classes from preprocess to templates.

I'm wary of {{ item.value }}. This is not "the value", a field item is a map of properties/values. And in some basic field types there is one single property named 'value' - see the potential for confusion here ?

If we have to put several things in the "item" var, then I'd suggest item.content rather than item.value for "the HTML string for the formatted FieldItem".

Good point yched. Here is a updated patch where item.value is changed to item.content.

I'm fine with .content

However:
- The different syntax ({{ item['#attributes'] }} / {{ item.content }}), introduced in the recent versions of the patch, somewhat nullifies the interest of the change to begin with ?
- The docs in the various field*.html.twig (and the issue summary, btw) need to be updated for that new #attributes syntax. Setting back to NW for that.
- I don't see @mortendk in the discussion here. He had a large effort to refactor the field templates in #2214241: Field default markup - removing the divitis. I'm not sure what's the status of that, I'm pinging him over there.

We kinda got intro fixing the bigger issue of classname generated in the preprocess - aka the banana concensus.
Lets do a face to face talk at the sprint in amsterdam ?

Going back to attribute without number sign.

Seems to be working just fine, setting to RTBC. If anyone else comes up with problems with this, please change the status back again.

+++ b/core/modules/node/templates/field--node--title.html.twig
@@ -8,11 +8,17 @@
- * - items: List of all the field items.
+ * - items: List of all the field items. Each item contains:
+ *   - attributes: List of HTML attributes for each item.
+ *   - content: The field item content.

Can we make this docs modification to field--node--uid.html.twig and field--node--created as well please?

Setting back to rtbc based on lauriii's interdiff.

putting back to rtbc

Less loops++ nice work.

Committed cbd36ff and pushed to 8.0.x. Thanks!