Upgrade/Install: Skip registering theme block patterns during the upgrade process.

This fixes a bug during the database upgrade process where a theme's `functions.php` file may not be loaded, leading to potential exceptions if the theme's pattern files use symbols (classes, functions, constants, etc.) that are declared only when the `functions.php` file is loaded. To do so, a check for `wp_get_active_and_valid_themes()` is added early to `_register_theme_block_patterns()`, which returns early if no active or valid themes are returned.

Props fabiankaegy, rajinsharwar, pbiron, huzaifaalmesbah, hellofromTonya, peterwilsoncc, joemcgill.
Fixes #59723.

Built from https://develop.svn.wordpress.org/trunk@57021


git-svn-id: http://core.svn.wordpress.org/trunk@56532 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/block-patterns.php

@@ -328,6 +328,17 @@ function _register_remote_theme_patterns() {
  * @access private
  */
 function _register_theme_block_patterns() {
+
+	/*
+	 * During the bootstrap process, a check for active and valid themes is run.
+	 * If no themes are returned, the theme's functions.php file will not be loaded,
+	 * which can lead to errors if patterns expect some variables or constants to
+	 * already be set at this point, so bail early if that is the case.
+	 */
+	if ( empty( wp_get_active_and_valid_themes() ) ) {
+		return;
+	}
+
 	/*
 	 * Register patterns for the active theme. If the theme is a child theme,
 	 * let it override any patterns from the parent theme that shares the same slug.

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57019';
+$wp_version = '6.5-alpha-57021';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.