Admin Context: Fix PHP fatals when admin.php has CRLF line endings (#…

…5875)

If `wp-admin/admin.php` has CRLF line endings, running `wp
--context=admin` with any command results in a PHP fatal error because
the regular expression to strip the wp-load.php require statement

features/context.feature

@@ -176,3 +176,20 @@ Feature: Context handling via --context global flag
       """
       custom context was added
       """
+
+  Scenario: Core wp-admin/admin.php with CRLF lines does not fail.
+    Given a WP install
+    And a modify-wp-admin.php file:
+    """
+    <?php
+    $admin_php_file = file( __DIR__ . '/wp-admin/admin.php' );
+    $admin_php_file = implode( "\r\n", array_map( 'trim', $admin_php_file ) );
+    file_put_contents( __DIR__ . '/wp-admin/admin.php', $admin_php_file );
+    unset( $admin_php_file );
+    """
+
+    When I run `wp --require=modify-wp-admin.php --context=admin eval 'var_export( is_admin() );'`
+    And STDOUT should be:
+    """
+    true
+    """

php/WP_CLI/Context/Admin.php

@@ -114,7 +114,7 @@ private function load_admin_environment() {
 		$admin_php_file = preg_replace( '/\s+\?>$/', '', $admin_php_file );
 
 		// Then we remove the loading of either wp-config.php or wp-load.php.
-		$admin_php_file = preg_replace( '/^\s*(?:include|require).*[\'"]\/?wp-(?:load|config)\.php[\'"]\s*\)?;$/m', '', $admin_php_file );
+		$admin_php_file = preg_replace( '/^\s*(?:include|require).*[\'"]\/?wp-(?:load|config)\.php[\'"]\s*\)?;\s*$/m', '', $admin_php_file );
 
 		// We also remove the authentication redirect.
 		$admin_php_file = preg_replace( '/^\s*auth_redirect\(\);$/m', '', $admin_php_file );