Fatal error: Attempt to read property "ID" on null in /src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php

[antonvlasenko]

This error occurs when a user tries to fetch autosave posts or revisions for a template (template part) that is file-based and does not have an associated entity in the posts table.
The returned HTTP code is 403, which is also incorrect.
Both the fatal error and the HTTP code need to be fixed.

[antonvlasenko]

Props to @Mamaduka for discovering this issue.

Trac ticket: https://core.trac.wordpress.org/ticket/61970

[antonvlasenko]

Steps to test ​https://github.com/WordPress/wordpress-develop/pull/7272:

1. On a fresh installation of WordPress, activate the Twenty Twenty-Four theme.
2. Send GET requests to the following endpoints:

• /wp-json/wp/v2/templates/twentytwentyfour//search/revisions/1
• /wp-json/wp/v2/templates/twentytwentyfour//search/autosaves
• /wp-json/wp/v2/template-parts/twentytwentyfour//header/revisions/1
• /wp-json/wp/v2/template-parts/twentytwentyfour//header/autosaves

3. Observe that there are no REST API-related fatal PHP errors in the logs and that you receive the following REST API responses:

      
      {
        "code": "rest_invalid_template",
        "message": "Templates based on theme files can't have revisions.",
        "data": {
          "status": 400
        }
      }
   

P.S. While manual testing is important, the aforementioned PR contains unit tests that verify the endpoint returns the correct response.

This is looking good so for. Needs testing.

Thank you for the review, @spacedmonkey.
I’ve added testing instructions and fixed the failing PHPUnit tests.

[antonvlasenko]

Test Report

This report validates that the indicated patch addresses the issue.

Patch tested: ​https://github.com/WordPress/wordpress-develop/pull/7272

Environment

• WordPress: 6.7-beta2-59195-src
• PHP: 8.3.3
• Server: Apache/2.4.57 (Unix) PHP/8.3.3
• Database: mysqli (Server: 5.7.43 / Client: mysqlnd 8.3.3)
• Browser: Safari 18.0 (macOS)
• Theme: Twenty Twenty-Four 1.2
• MU-Plugins: None activated
• Plugins:
  • Datetime
  • Gutenberg 19.1.0
  • WordPress Beta Tester 3.5.3

Actual Results

• ✅ Template revisisions endpoint returns correct HTTP response code (400) for files based templates and template parts.
• ✅ Template autosaves endpoint returns correct HTTP response code (400) for files based templates and template parts.

Supplemental Artifacts

P.S. Apologies for the visual noise caused by the attached files below.

[kadamwhite]

Thanks for the patch, and the testing. Added 6.8 milestone to get this in early next cycle once we're out of 6.7 RC!

[swissspidy]

In 59605:

REST API: Improve autosave and revision endpoints for templates and template parts.

Fixes those endpoints for file-based templates and template parts, as templates based on theme files can't be revisioned or autosaved.

Props antonvlasenko, swissspidy, spacedmonkey, kadamwhite.
Fixes #61970.

Committed in https://core.trac.wordpress.org/changeset/59605

[swissspidy]

In 59607:

Undo accidental svn:mergeinfo property change in [59605].

See #61970.