WP Super Cache: don't define DONOTCACHEPAGE without checking if it's …

…defined (#36423)

* Check if DONOTCACHEPAGE is defined before setting it.

ref:
https://wordpress.org/support/topic/warning-constant-donotcachepage-already-defined/

* changelog

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/8319226494

CHANGELOG.md

@@ -12,6 +12,9 @@ This is an alpha version! The changes listed here are not final.
 ### Changed
 - Updated package dependencies.
 
+### Fixed
+- WP Super Cache: do not define DONOTCACHEPAGE if it is already defined
+
 ## [1.12.0] - 2024-03-11
 ### Added
 - Setup: Detect Jetpack Boost cache and suggest troubleshooting steps [#36018]

wp-cache-phase1.php

@@ -29,7 +29,9 @@
 if ( '/' === $cache_path || empty( $cache_path ) ) {
 	define( 'WPSCSHUTDOWNMESSAGE', 'WARNING! Caching disabled. Configuration corrupted. Reset configuration on Advanced Settings page.' );
 	add_action( 'wp_footer', 'wpsc_shutdown_message' );
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	return;
 }
 
@@ -55,7 +57,9 @@
 // from the secret shown on the Advanced settings page.
 if ( isset( $_GET['donotcachepage'] ) && isset( $cache_page_secret ) && $_GET['donotcachepage'] == $cache_page_secret ) {
 	$cache_enabled = false;
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 }
 
 // Load wp-super-cache plugins
@@ -109,21 +113,27 @@
 
 // don't cache in wp-admin
 if ( wpsc_is_backend() ) {
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	return true;
 }
 
 // if a cookie is found that we don't like then don't serve/cache the page
 if ( wpsc_is_rejected_cookie() ) {
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	$cache_enabled = false;
 	wp_cache_debug( 'Caching disabled because rejected cookie found.' );
 	return true;
 }
 
 if ( wpsc_is_caching_user_disabled() ) {
 	wp_cache_debug( 'Caching disabled for logged in users on settings page.' );
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	return true;
 }
 
@@ -142,13 +152,17 @@
 // don't cache or serve cached files for various URLs, including the Customizer.
 if ( isset( $_SERVER['REQUEST_METHOD'] ) && in_array( $_SERVER['REQUEST_METHOD'], array( 'POST', 'PUT', 'DELETE' ), true ) ) {
 	wp_cache_debug( 'Caching disabled for non GET request.' );
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	return true;
 }
 
 if ( isset( $_GET['customize_changeset_uuid'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
 	wp_cache_debug( 'Caching disabled for customizer.' );
-	define( 'DONOTCACHEPAGE', 1 );
+	if ( ! defined( 'DONOTCACHEPAGE' ) ) {
+		define( 'DONOTCACHEPAGE', 1 );
+	}
 	return true;
 }