REST API: Declare 'edit_css' capability in links within `WP_REST_Glob…

…al_Styles_Controller`.

Updates the Global Styles endpoint to expose the `'edit_css'` capability via action links.

References:
* [WordPress/gutenberg#46815 Gutenberg PR 46815] Part of an effort to hide custom CSS setting for users without `'edit_css'` capability.

Follow-up to [52342], [52051].

Props mamaduka, dsas, glendaviesnz, mmtr86, talldanwp, timothyblynjacobs.
Fixes #57526.

git-svn-id: https://develop.svn.wordpress.org/trunk@55177 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/rest-api/endpoints/class-wp-rest-global-styles-controller.php

@@ -431,6 +431,7 @@ protected function prepare_links( $id ) {
 	 * Get the link relations available for the post and current user.
 	 *
 	 * @since 5.9.0
+	 * @since 6.2.0 Added 'edit-css' action.
 	 *
 	 * @return array List of link relations.
 	 */
@@ -442,6 +443,10 @@ protected function get_available_actions() {
 			$rels[] = 'https://api.w.org/action-publish';
 		}
 
+		if ( current_user_can( 'edit_css' ) ) {
+			$rels[] = 'https://api.w.org/action-edit-css';
+		}
+
 		return $rels;
 	}
 

tests/phpunit/tests/rest-api/rest-global-styles-controller.php

@@ -513,4 +513,23 @@ public function test_get_theme_items() {
 		);
 		$this->assertSameSetsWithIndex( $data, $expected );
 	}
+
+	/**
+	 * @covers WP_REST_Global_Styles_Controller::get_available_actions
+	 */
+	public function test_assign_edit_css_action_admin() {
+		wp_set_current_user( self::$admin_id );
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/global-styles/' . self::$global_styles_id );
+		$request->set_param( 'context', 'edit' );
+		$response = rest_do_request( $request );
+		$links    = $response->get_links();
+
+		// Admins can only edit css on single site.
+		if ( is_multisite() ) {
+			$this->assertArrayNotHasKey( 'https://api.w.org/action-edit-css', $links );
+		} else {
+			$this->assertArrayHasKey( 'https://api.w.org/action-edit-css', $links );
+		}
+	}
 }