Quick Edit doesn't work for Custom Blocks referenced by other Custom Blocks

Could you record & post a screencast demonstrating the problem? Thanks.

I'm seeing this in Entity Reference fields on Content/Content Blocks. Replication steps for this issue (from stock Drupal 8 install):

1) Visit /admin/structure/block/block-content/manage/basic/fields/add-field
2) Add a Reference > Other field, move on to the next screen, then reference Content Blocks. Continue through the form using default settings.
3) Visit /admin/structure/block/block-content/manage/basic/display, change format for your new field to to "Rendered entity"
4) Create a block at /block/add/basic, fill in the Title and Body fields
5) Don't place this block in a region (it will be out nested block)
6) Create another block at /block/add/basic, fill in the Title and Body fields, and in your Entity Reference field reference the block created in step (4)
7) Place this block in a visible region
8) Visit any page that renders that block
9) See that in the browser console, the error "Uncaught TypeError: Cannot read property 'getAttribute' of undefined" is thrown

Possibly related issues: #2658270: BlockViewBuilder::preRender() must not mess with block render arrays / #2666578: Block Content entities have no Contextual links when rendered outside of Block config entity

I have confirmed this, I was able to replicate this issue.

The STR are there, which is great. But there's nothing there yet about the JS error. Which JS file is throwing that error? Are you sure it's not Contextual Links?

This seems somewhat related to #2551373: contextual.js and quickedit.js should fail gracefully, with useful error messages, when Twig templates forget to print attributes.

The error is not very helpful, would need to backtrace
drupal.js?v=8.1.0:67 Uncaught TypeError: Cannot read property 'getAttribute' of undefined

Perhaps @mortenson can provide moe information here.

Just reproduce the error with JS aggregation disabled, then look at the stack trace. You'll see where (in which JS) it was triggered.

drupal.js?v=8.1.0:67 Uncaught TypeError: Cannot read property 'getAttribute' of undefined
processField @ quickedit.js?v=8.1.0:380(anonymous function) @ quickedit.js?v=8.1.0:93
n.extend.each @ jquery.js:374
n.fn.n.each @ jquery.js:139
Drupal.behaviors.quickedit.attach @ quickedit.js?v=8.1.0:92
Drupal.attachBehaviors @ drupal.js?v=8.1.0:168
(anonymous function) @ drupal.js?v=8.1.0:178
n.addEventListener.t @ ready.min.js?v=1.0.8:4

Ok, so it's happening in the processField() function. Putting a breakpoint in there would allow you to see which HTML expectations Quick Edit has that are not being met.

I've uploaded some screenshots which show the debugging process - basically it looks like there is no [data-quickedit-entity-id] wrapping element for child Custom Blocks, which as noted in the original issue summary could be related to #2666578: Block Content entities have no Contextual links when rendered outside of Block config entity. Also verified that the original STR are still valid in 8.1.0.

Not changing the issue status in case more information is needed.

Had the same issue, a check to see if entityElement.get(0) is defined seems to fix it. Please be gentle - this is my first core patch :)

#14 Corrects the error and I am capable of editing the custom block in the custom block. The other fields are also still editable.

I think this patch should be added to make quickedit.js more robust. The related issue https://www.drupal.org/node/2666578 should also help fix this but quickedit.js needs more value checking. It is too fragile.

I guess I missed this patch showing up, but just saw it now. I tested it out and it seems to work good in my situation.

This needs test coverage.

I intend to work on Quick Edit JS test coverage in the coming weeks.

Postponing on #2828528: Add Quick Edit Functional JS test coverage.

See #2828528-26: Add Quick Edit Functional JS test coverage, that now has explicit test coverage for starting the in-place editing of custom blocks.

#14 looks like a work-around, not a fix. AFAICT it will just ignore every field for a nested entity, whereas we need logic (and test coverage) to explicitly deal with that.

Also, #14 has a fix that is functionally identical to the patch for #2314185: [PP-1] DrupalBehaviorError: attach ; quickedit: entityElement.get(...) is undefined.

AFAICT this was fixed in #2551373: contextual.js and quickedit.js should fail gracefully, with useful error messages, when Twig templates forget to print attributes.