Content fields don't update in Live preview when editing "Current" version, using custom preview target

[michaelrog]

I've noticed a phenomenon where field values don't live-update in Live Preview when I'm editing the "Current" version (prior to an auto-save).

Here's my setup:

• Preview Target URI:

  _livePreview/issues/homepage/{canonicalId}

• Route entry:

  '_livePreview/issues/homepage/<id>' => ['template' => '_livePreview/issues/homepage'],

• Template (_livePreview/issues/homepage):

  {% set issue = craft.entries.section('issues').id(id).one() %}
  {% dd(issue) %}

And here's the weirdness:

1. Load entry edit page — version dropdown shows "Current" — and launch Live Preview.
2. Edit some field values. Dumped element data in template shows previewing => true but field values are not live-updating. (_canonicalId and _canonical are both null.)
3. Reload entry edit page without explicitly Saving — version dropdown shows "Current - Edited" — and launch Live Preview.
4. Edit some field values. Now the custom field values are live-updating. (_canonicalId and _canonical now have values, too.)

---

• Craft version: 3.7.28 (Pro)
• PHP version: 8.0
• Database driver & version: MySQL
• Packages

  "aelvan/imager": "^2.4",
  "craftcms/aws-s3": "^1.2",
  "craftcms/redactor": "^2.0",
  "nystudio107/craft-retour": "^3.1",
  "nystudio107/craft-vite": "^1.0",
  "topshelfcraft/environment-label": "^3.2",
  "topshelfcraft/wordsmith": "3.3.0.1",

[brandonkelly]

Are you seeing any JavaScript errors?

[michaelrog]

No errors, but a couple warnings that might be relevant...?

Couldn’t save draft: Form already being submitted. (DraftEditor.js:771:26)

Some cookies are misusing the “SameSite“ attribute, so it won’t work as expected 

[brandonkelly]

Try editing an entry with the Network tab open. When you start making changes, is there an Ajax request that isn’t resolving?

[michaelrog]

Try editing an entry with the Network tab open. When you start making changes, is there an Ajax request that isn’t resolving?

Network activity looks normal; No unresolved requests.

[brandonkelly]

Wonder if this is the same bug as #10257. Can you try updating craftcms/cms to dev-develop as 3.7.28 and see if the issue persists?

[michaelrog]

Wonder if this is the same bug as #10257. Can you try updating craftcms/cms to dev-develop as 3.7.28 and see if the issue persists?

Doesn't seem to solve this one, I'm afraid...

[brandonkelly]

Can you send your project files into support@craftcms.com? (Database, Composer files, templates, config/routes.php, and any custom plugins/modules you’ve got.)

[michaelrog]

Can you send your project files into support@craftcms.com? (Database, Composer files, templates, config/routes.php, and any custom plugins/modules you’ve got.)

yessir, will try to package up a minimal reproduction for you. 👍