Administration: Reduce the chance that a PHP error message that occurs before the admin menu gets output is covered by the admin menu.

Props EmpireOfLight, afercia, Mte90, audrasjb, sunnyratilal

Fixes #35155

git-svn-id: https://develop.svn.wordpress.org/trunk@47745 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/admin-header.php

@@ -200,6 +200,11 @@ if ( $current_screen->is_block_editor() ) {
 	}
 }
 
+// Print a CSS class to make PHP errors visible.
+if ( error_get_last() && WP_DEBUG && WP_DEBUG_DISPLAY && ini_get( 'display_errors' ) ) {
+	$admin_body_class .= ' php-error';
+}
+
 ?>
 </head>
 <?php

src/wp-admin/css/admin-menu.css

@@ -13,6 +13,15 @@
 	z-index: 1; /* positive z-index to avoid elastic scrolling woes in Safari */
 }
 
+.php-error #adminmenuback {
+	position: absolute;
+}
+
+.php-error #adminmenuback,
+.php-error #adminmenuwrap {
+	margin-top: 2em;
+}
+
 #adminmenu {
 	clear: left;
 	margin: 12px 0;