From 5225d192ac27762f37628244f3b70ba6f60defee Mon Sep 17 00:00:00 2001
From: Jorge Costa <jorge.costa@developer.pt>
Date: Mon, 19 Oct 2026 21:50:48 +0100
Subject: [PATCH] Editor: Preload the entity fields of the post editor.

The post summary of the post editor's inspector reads the fields of the edited post type from the `/wp/v2/entity-fields` route since Gutenberg stabilized the DataForm-based inspector, so the post editor now preloads them, as the site editor does.

Follow-up to [64528].

See #66339.
---
 src/wp-includes/entity-fields.php             | 27 +++++++++----------
 .../entity-fields/wpPreloadEntityFields.php   | 11 ++++----
 2 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/src/wp-includes/entity-fields.php b/src/wp-includes/entity-fields.php
index 91a0547557a3e..3f6a87039f9dd 100644
--- a/src/wp-includes/entity-fields.php
+++ b/src/wp-includes/entity-fields.php
@@ -323,16 +323,13 @@ function _wp_get_site_editor_screen_post_types() {
 }
 
 /**
- * Preloads the fields of the post types the site editor lists.
+ * Preloads the fields of the post types the editors list.
  *
- * The site editor reads them from the `/wp/v2/entity-fields` route before it
- * can list the post fields, see `useFields` in
- * packages/editor/src/dataviews/fields-loader/index.ts in Gutenberg: those of
- * the edited post, if any, and of the post types of the screen it opens on.
- *
- * The post editor is left untouched: it only reads the fields in the
- * DataForm-based inspector, an experiment of the Gutenberg plugin which
- * preloads them on its own.
+ * The editors read them from the `/wp/v2/entity-fields` route, see `useFields`
+ * in packages/editor/src/dataviews/fields-loader/index.ts in Gutenberg. The
+ * post editor reads those of the edited post in the post summary of its
+ * inspector. The site editor reads those of the edited post, if any, and of
+ * the post types of the screen it opens on.
  *
  * @since 7.2.0
  * @access private
@@ -342,15 +339,15 @@ function _wp_get_site_editor_screen_post_types() {
  * @return array Filtered preload paths.
  */
 function _wp_preload_entity_fields( $paths, $context ) {
-	if ( 'core/edit-site' !== $context->name ) {
-		return $paths;
-	}
-
 	$post_types = array();
-	if ( isset( $context->post ) ) {
+	if ( 'core/edit-post' === $context->name && isset( $context->post ) ) {
 		$post_types[] = $context->post->post_type;
+	} elseif ( 'core/edit-site' === $context->name ) {
+		if ( isset( $context->post ) ) {
+			$post_types[] = $context->post->post_type;
+		}
+		$post_types = array_merge( $post_types, _wp_get_site_editor_screen_post_types() );
 	}
-	$post_types = array_merge( $post_types, _wp_get_site_editor_screen_post_types() );
 
 	return array_merge(
 		$paths,
diff --git a/tests/phpunit/tests/entity-fields/wpPreloadEntityFields.php b/tests/phpunit/tests/entity-fields/wpPreloadEntityFields.php
index 064fbbf063566..679de5edc5848 100644
--- a/tests/phpunit/tests/entity-fields/wpPreloadEntityFields.php
+++ b/tests/phpunit/tests/entity-fields/wpPreloadEntityFields.php
@@ -32,12 +32,13 @@ public function test_the_fields_are_preloaded_on_the_block_editor_preload_paths(
 	}
 
 	/**
-	 * The post editor does not preload the fields, whatever its `p` query arg.
+	 * The post editor preloads the fields of the edited post type, which the
+	 * post summary of its inspector reads, whatever its `p` query arg.
 	 *
-	 * @ticket 66229
+	 * @ticket 66339
 	 */
-	public function test_the_post_editor_does_not_preload_the_fields() {
-		$_GET['p'] = '/page';
+	public function test_the_post_editor_preloads_the_fields_of_the_post_type() {
+		$_GET['p'] = '/wp_template';
 		$post      = self::factory()->post->create_and_get( array( 'post_type' => 'page' ) );
 		$context   = new WP_Block_Editor_Context(
 			array(
@@ -46,7 +47,7 @@ public function test_the_post_editor_does_not_preload_the_fields() {
 			)
 		);
 
-		$this->assertSame( array(), _wp_preload_entity_fields( array(), $context ) );
+		$this->assertSame( array( '/wp/v2/entity-fields?kind=postType&name=page' ), _wp_preload_entity_fields( array(), $context ) );
 	}
 
 	/**