Add a Media Library views template to Seven theme to change to order of the views header and exposed filters

What's the correct tag to mark this as a minor release blocker?

I'm not sure, but I'm marking this as a triaged critical per the discussion summarized in #2981044-64: Unify the grid/table views of the media library. Once this is unblocked, we should escalate its priority to critical.

#2981044: Unify the grid/table views of the media library is in.

This is actually postponed on Media Library becoming stable, so it’s not quite time to open this back up yet. :)

Fixing tagging.

I added this to the scope of #3082690: Mark Media Library as a stable core module. We might end up with this issue marked as a duplicate of that one as they should probably be fixed in the same patch (rather than as a followup) since it's a critical accessibility issue.

Although this is technically postponed, this is work that can continue as it can't be committed until media library is stable in #3082690: Mark Media Library as a stable core module but the actual development does not depend on that issue.

This patch adds a test and addresses four @todo's that reference this issue.

This looks ready :)

Is the needs accessibility review tag still applicable here?

I've been watching this issue sure enough; it was me who asked for this in one of the UX calls. The "needs accessibility review" tag was appropriate, because we knew this issue could be postponed for many months and the module code could have changed in the meantime.

The solution is correct, and straight-forward enough. Flexbox order is a huge problem when it's used to rearrange interactive elements (or containers with interactive elements). The relevant WCAG success criteria are 1.3.2 Meaningful Sequence (level A) and 2.4.3 Focus Order (level A).

I manually tested patch #11 today, and it's working as intended.

The test in #11 is a bit spurious:

+    // Assert that the media library view has the filter appearing before the
+    // header in the DOM. This is needed for accessibility.

That's not actually what we're interested in. By itself, the DOM order doesn't matter here. What matters is that the DOM order, the tabbing order, and the visual presentation order are in harmony. From Understanding 2.4.3 Focus Order:

when the order of a particular presentation differs from the programmatically determined reading order, users of one of these presentations may find it difficult to understand or operate the Web page. [...]

For example, a screen reader user interacts with the programmatically determined reading order, while a sighted keyboard user interacts with the visual presentation of the Web page. Care should be taken so that the focus order makes sense to both of these sets of users and does not appear to either of them to jump around randomly.

The test in #11 doesn't really protect that. Later changes could disrupt the tabbing order with tabindex attributes, or disrupt the visual focus order with flexbox order. Either of these would be bad for SC 2.4.3 Focus Order, but the test here would still pass. Unless we can get a test which looks at the the whole combination of DOM order, tabbing order, and visual order, then I don't think it's worth having a test at all.

I manually tested patch #11 today, and it's working as intended.

Great! That means accessibility review is now completed, and this is only blocked on A) the module becoming stable, B) the test being improved based on #14. Consider this virtually marked Needs work :)

Cool -- let's update the tests on this now. @phenaproxima suggested keeping this issue rerolled once it's RTBCable, and ready for commit when we mark the module stable.

Just to clarify #14 - I don't think this is possible to test.

#17 Makes sense, here's the patch without a test.

So that means this is virtually RTBC, but it cannot be committed until the Media Library module is marked stable. Marking Postponed to avoid us continuing to look at this until that time.

To clarify: this is blocked on #3082690: Mark Media Library as a stable core module becoming unblocked 🤓

At @lauriii's request, posting a diff between Classy's views-view.html.twig and the variant we're adding to Seven in this patch.

Thanks for the diff @phenaproxima!

+++ core/themes/seven/templates/views-view--media_library.html.twig	2019-10-07 12:05:18.000000000 -0400
@@ -32,12 +32,12 @@
-    'view',
-    'view-' ~ id|clean_class,
-    'view-id-' ~ id,
-    'view-display-id-' ~ display_id,
-    dom_id ? 'js-view-dom-id-' ~ dom_id,
-  ]
+  'view',
+  'view-' ~ id|clean_class,
+  'view-id-' ~ id,
+  'view-display-id-' ~ display_id,
+  dom_id ? 'js-view-dom-id-' ~ dom_id,
+]

This looks unrelated change. Let's revert this. Other than that, this looks great!

Made changes as suggested by @lauriii in #22.

Thanks, @JeroenT!

@lauriii, @bnjmnm, and I reviewed this issue in Zoom today. Except for the indentation issue (now fixed), Lauri said this is committable. So consider that a "virtual" commit, blocked on making Media Library stable. 🎉

Beyond any needed rerolls, there is no need for any further work on this patch.

Marking this issue fixed, because it has been "virtually committed" by @lauriii and rolled into the big patch being built in #3082690: Mark Media Library as a stable core module. No further work should take place here; I'll transfer credit into the other issue.