Revisions API do not initialize GLOBALS['post']

[pdufour]

Calling functions like get_post() do not work within the Post Revisions API endpoint since they don't have a line like $GLOBALS['post'] = $post; which the posts controller does have ​https://github.com/WordPress/WordPress/blob/4.7.4/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php#L1381-L1383.

Fix if I understand the issue would be to add those two lines to prepare_item_for_response in the revisions controller.

[jnylen0]

Thanks for the report and the patch. There are two super-minor whitespace issues in 40626-add-global.patch​:

• Blank line added to the beginning of the test file
• Extra space in $parent_post_id = wp_is_post_revision ( $post->ID );

As far as the change itself, I can't think of any unintended effects this would have. Anyone else? Otherwise let's get this committed soon.

[pdufour]

Done! Thanks for the quick review @jnylen0.

[joehoyle]

Unless it's needed, I'm not sure _why_ we would want to add this. I believe they are there in the Posts Controller because there's some internal WP functions that require these globals to be set, so we had to make $post global. If that's not explicitly needed in the revisions endpoint, I don't think we should add it. All filters in the Revisions controller should get passed the Request or WP_Post object, so I'm not sure why you'd want to do get_post() with not ID param.

[pdufour]

Shortcodes @joehoyle

[rmccue]

This is primarily for compatibility with existing deep filters inside WP core, so +1 on this. Patch looks good to me as well.

[rmccue]

In 40601:

REST API: Set global $post when preparing revisions.

For compatibility with filters on hooks on content filters (such as shortcodes), we need to set the global. This mirrors the Posts controller.

Props pdufour, jnylen0.
Fixes #40626.

[ocean90]

#40887 was marked as a duplicate.

[westonruter]

In 62952:

REST API: Restore the global post after preparing a revision.

WP_REST_Revisions_Controller::prepare_item_for_response() set the global $post to the revision being prepared and called setup_postdata(), but never restored the previous value, so the change persisted for the remainder of the request. WP_REST_Autosaves_Controller delegates to this method and the block editor preloads the autosaves endpoint on every load, so a post with a pending autosave could leave the global $post pointing at the autosave revision while edit-form-blocks.php built the editor bootstrap, initializing the editor with the wrong post and rewriting the URL to it.

The previous global $post is now captured before setup_postdata() and restored on every return path, including the early return for HEAD requests.

Developed in ​https://github.com/WordPress/wordpress-develop/pull/12248.
Follow-up to r40601, r59899.

Props micahele, gusgomezpg, westonruter, wildworks, dhrupo.
See #40626, #43502.
Fixes #65495.