Themes: Introduce the `delete_theme` and `deleted_theme` action hooks.

This change introduces the `delete_theme` and `deleted_theme` action hooks, which fire immediately before and after an attempt to delete a theme, respectively.

Props scottconnerly, ptahdunbar, pbiron, vetyst, desrosj.
Fixes #16401.
Built from https://develop.svn.wordpress.org/trunk@50826


git-svn-id: http://core.svn.wordpress.org/trunk@50435 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/theme.php

@@ -72,10 +72,29 @@ function delete_theme( $stylesheet, $redirect = '' ) {
 		return new WP_Error( 'fs_no_themes_dir', __( 'Unable to locate WordPress theme directory.' ) );
 	}
 
+	/**
+	 * Fires immediately before a theme deletion attempt.
+	 *
+	 * @since 5.8
+	 *
+	 * @param string $stylesheet Stylesheet of the theme to delete.
+	 */
+	do_action( 'delete_theme', $stylesheet );
+
 	$themes_dir = trailingslashit( $themes_dir );
 	$theme_dir  = trailingslashit( $themes_dir . $stylesheet );
 	$deleted    = $wp_filesystem->delete( $theme_dir, true );
 
+	/**
+	 * Fires immediately after a theme deletion attempt.
+	 *
+	 * @since 5.8
+	 *
+	 * @param string $stylesheet Stylesheet of the theme to delete.
+	 * @param bool   $deleted    Whether the theme deletion was successful.
+	 */
+	do_action( 'deleted_theme', $stylesheet, $deleted );
+
 	if ( ! $deleted ) {
 		return new WP_Error(
 			'could_not_remove_theme',

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50825';
+$wp_version = '5.8-alpha-50826';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.