Update CKEditor library to 4.5.5

Great! (IIRC the only reason this was critical is because #2203431: [meta] Various asset (JavaScript) libraries have to be updated to a (minified) stable release prior to 8.0.0 mandated it.)

#2521820: Update CKEditor library to 4.5.3 is bringing us the latest version, on September 22, CKEditor will release version 4.5.4. If RC1 is tagged before then, we'll be able to close this. But I think we'll want to update to 4.5.4 before release. So, keeping this issue open for now.

I talked to the CKEditor people. Version 4.5.4 was marked for September 22, but will be postponed until early October at least. I should hope we have tagged RC by then. So, retitling accordingly: the CKEditor module is ready for RC1 :)

Now updating to 4.5.4: #2581291: Update CKEditor library to 4.5.4.

And now we have confirmation that the final CKEditor release before 8.0.0 will be CKEditor 4.5.5.

It will be released on November 11 (one week after RC3, one week before 8.0.0). I've got confirmation from several core committers that it's going to be okay to update to that version. Especially because it will contain some bugfixes that Drupal 8 needs, most notably:

• http://dev.ckeditor.com/ticket/13885 for #2510380: Images cannot be linked in CKEditor
• http://dev.ckeditor.com/ticket/13886 for #2598070: [regression] CKEditor Link button does not show if HTML filtering is enabled

I do think it's valuable for #2581291: Update CKEditor library to 4.5.4 to still go in in the mean time, because it will make the difference in CKEditor between 8.0.0 RC3 and 8.0.0 final smaller, thus further reducing the risk.

Woot, thank you! :)

Turns out we actually won't need the CKEditor 4.5.5 release to fix our problems. Upgrading to CKEditor 4.5.5 and updating our accompanying code is now effectively a nice-to-have. Of course, we probably still want to upgrade to CKEditor 4.5.5 just to ship with the latest stable of all (asset) libraries. But bug-wise/functionality-wise, it is now completely optional.

So, if we choose even lower risk by not updating to CKEditor 4.5.5, that is possible.

For now, there are very few bugfixes in 4.5.5 that are relevant to Drupal 8: http://dev.ckeditor.com/query?group=status&milestone=CKEditor+4.5.5.

We can evaluate whether we want to update to 4.5.5 when it is released.

Well, turns out CKEditor doesn't work in IE9 because Drupal uses the classList polyfill. This already was a known CKEditor bug, and should be fixed in 4.5.5: http://dev.ckeditor.com/ticket/13867. Which means we again have a good reason to update to CKEditor 4.5.5. See #2607362: CKEditor does not load in IE9.

http://dev.ckeditor.com/ticket/13885 landed, which will allow us to simplify some of what we did in #2510380: Images cannot be linked in CKEditor.

4.5.5 was released late yesterday: http://ckeditor.com/blog/CKEditor-4.5.5-Released.

Working on patch.

@DuaelFr :) :)

I will post three patches here:

1. (This one.) Just the update to CKEditor 4.5.5, nothing else.
2. Per #20, 4.5.5 allows us to leverage CKEditor ticket 13885: we can incorporate the simplification interdiff in #2510380-75: Images cannot be linked in CKEditor.
3. #2608434: Links on images can only have href attribute hugely overlaps with point 2 and it already is RTBC. So, I can just merge that patch into this one.

Please only start manual testing once I've posted the third patch.

Second patch. See #23.

(Again: this is #2510380-75: Images cannot be linked in CKEditor applied without any changes, just rebased.)

Third patch. See #23.

Merged in from the RTBC patch at #2608434-11: Links on images can only have href attribute.

EDIT: sadly, the interdiff attached here is wrong. The right one: interdiff.txt.

So, a CKEditor team person reviewing the individual interdiffs in #24 and #25 would be valuable, but perhaps a combined interdiff showing the entire set of differences between #23 and #25 would be handier. So, uploading a #23-to-#25 interdiff here.

Ready for review!

Fuck, #25's interdiff is wrong. Sorry :(

Here's the correct interdiff for #25.

LOL!

#2608434: Links on images can only have href attribute got committed in the mean time, so … #25's interdiff is already in core. So, rerolling now.

In the process of rerolling this patch because of #28, I discovered that that commit introduced a regression: #2608434-15: Links on images can only have href attribute.

Therefore, I think it's safer to just commit #23, the pure CKEditor upgrade. We can clean up our internal implementation during the 8.0.x cycle; what matters most is that we upgrade to CKEditor 4.5.5, not the clean-up to our plugins that CKEditor 4.5.5 enables.

So… let's ignore #23-#28. And let's just upgrade CKEditor. That's much lower risk.

This patch does exactly that (and is therefore identical to #23).

Sorry for the chaos.