REST API: Fix WP_REST_Autosaves_Controller silently preserving stale revision field by himanshupathak95 · Pull Request #12675 · WordPress/wordpress-develop

himanshupathak95 · 2026-07-24T07:02:59Z

Trac ticket: https://core.trac.wordpress.org/ticket/65694

When a post field (e.g. post_title) is reverted to the published value and an autosave is triggered via the REST API, WP_REST_Autosaves_Controller::create_post_autosave() silently skips the write if the submitted value matches the parent post — even when the existing autosave still holds a stale value from a prior edit.

The guard:

if ( ! $autosave_is_different && $old_autosave ) {
    return $old_autosave->ID;
}

compares incoming data against the parent post only. When that comparison returns equal, it returns the existing autosave ID without checking whether that autosave itself is already consistent with what was submitted.

Reproduce -

Save an autosave with title "My Post !!", then submit another with "My Post" (matching the published title).
The controller returns the old revision still holding "My Post !!" and no subsequent autosave can fix it, because every request with the correct title hits the same early return.

This PR expands the early-return guard to additionally compare the submitted fields against the existing autosave revision's fields using the same normalize_whitespace() loop already used earlier in the method. Only skip the update when the autosave is already consistent with the submitted data.

Testing

Manually reproduced the stale-title state and confirmed it is resolved with the fix.
New PHPUnit test covers the exact sequence from the ticket: modified autosave → revert → assert autosave is updated, tested by -

npm run test:php -- --filter=WP_Test_REST_Autosaves_Controller

…ished post

github-actions · 2026-07-24T07:06:18Z

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Pull request overview

This PR updates WP_REST_Autosaves_Controller::create_post_autosave() to prevent REST autosave updates from leaving stale values in an existing autosave revision (notably when a field is reverted back to the published post’s value), which impacts consumers like Preview that read from the autosave revision.

Changes:

Switches the “is this autosave different?” comparison to use the existing autosave revision (when present) rather than the published post.
Adds a meta-diff path against the existing autosave revision’s meta (when present) before deciding “nothing to save”.
Updates inline documentation to reflect the new comparison behavior.

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+			if ( ! $autosave_is_different && ! empty( $meta ) ) {
+				foreach ( $revisioned_meta_keys as $meta_key ) {
+					$old_meta_value = get_metadata_raw( 'post', $old_autosave->ID, $meta_key, true );
+					$new_meta_value = $meta[ $meta_key ] ?? '';



+		if ( $old_autosave ) {
+			/*
+			 * When an autosave revision already exists, compare the incoming data
+			 * against its current field values rather than the published post. A field
+			 * reverted to the published value - such as a title edit that was undone -
+			 * must still overwrite any stale value in the existing autosave, otherwise
+			 * consumers like Preview will display incorrect content indefinitely.
+			 */


… missing meta keys

github-actions · 2026-07-24T07:39:41Z

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

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Props abcd95.

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Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

+	 * @since 7.1.0 Compares incoming data against the existing autosave instead
+	 *              of the published post.


+		$controller->create_post_autosave( array(
+			'ID'         => $post_id,
+			'post_title' => 'Original Title !!',
+		) );
+
+		$controller->create_post_autosave( array(
+			'ID'         => $post_id,
+			'post_title' => 'Original Title',
+		) );
+
+		$autosave = wp_get_post_autosave( $post_id, self::$editor_id );
+		$this->assertSame( 'Original Title', $autosave->post_title );


Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php:374

The new @since note is misleading: this method does not always compare against an existing autosave, and it can apply to any saved post status (not just published). Updating this wording will keep the inline docs accurate for future maintainers.

	 * @since 7.1.0 Compares incoming data against the existing autosave instead
	 *              of the published post.

+				foreach ( $revisioned_meta_keys as $meta_key ) {
+					if ( ! array_key_exists( $meta_key, $meta ) ) {
+						continue;
+					}


himanshupathak95 added 5 commits July 24, 2026 12:26

Remove new line

8c319e6

Remove diff autosave flag

df2d93d

Remove redundant meta cheks

a241154

Update stale autosave fields when the submitted data matches the publ…

d39dd05

…ished post

Update doc block comment

d49a0c6

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himanshupathak95 added 2 commits July 24, 2026 13:07

ensure REST API autosaves correctly handle identical post content and…

61389da

… missing meta keys

Test create post autosave updates stale field on revert

94cef60

Copilot AI review requested due to automatic review settings July 24, 2026 07:38

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himanshupathak95 marked this pull request as ready for review July 24, 2026 07:39

Fix linting

cd87a39

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Copilot AI review requested due to automatic review settings July 24, 2026 07:42

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Comment thread src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php

Comment on lines +416 to +419

foreach ( $revisioned_meta_keys as $meta_key ) {

if ( ! array_key_exists( $meta_key, $meta ) ) {

continue;

}

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REST API: Fix WP_REST_Autosaves_Controller silently preserving stale revision field#12675

REST API: Fix WP_REST_Autosaves_Controller silently preserving stale revision field#12675
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himanshupathak95 commented Jul 24, 2026 •

edited

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		* @since 7.1.0 Compares incoming data against the existing autosave instead
		* of the published post.

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himanshupathak95 commented Jul 24, 2026 •

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