Upgrade/Install: Use a unique error code when an update fails due to the PHP JSON extension missing.

This allows update failures caused when the native PHP JSON extension is missing to be distinguished from updates that fail because the site does not meet the minimum PHP requirements.

Follow up of [46455].

Reviewed by desrosj, jorbin, johnbillion.
Fixes #47699.
Built from https://develop.svn.wordpress.org/trunk@46560


git-svn-id: http://core.svn.wordpress.org/trunk@46357 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/update-core.php

@@ -1004,7 +1004,7 @@ function update_core( $from, $to ) {
 	// Add a warning when the JSON PHP extension is missing.
 	if ( ! extension_loaded( 'json' ) ) {
 		return new WP_Error(
-			'php_not_compatible',
+			'php_not_compatible_json',
 			sprintf(
 				/* translators: 1: WordPress version number, 2: The PHP extension name needed. */
 				__( 'The update cannot be installed because WordPress %1$s requires the %2$s PHP extension.' ),

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-RC1-46559';
+$wp_version = '5.3-RC1-46560';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.