FormatJson: Skip whitespace cleanup when unnecessary

The patch[1] for PHP bug 66021[2], which removes the same undesirable
whitespace that WS_CLEANUP_REGEX does, has been merged into php-src.
Subsequent PHP versions having the patch shouldn't have to take the
10-20% performance hit from that workaround.

[1]: https://github.com/php/php-src/commit/82a4f1a1a287
[2]: https://bugs.php.net/bug.php?id=66021

Change-Id: I717a0e164952cc6ace104f13f6236e86c4ab8b58

diff --git a/includes/json/FormatJson.php b/includes/json/FormatJson.php
index 97d98a4..eb5e632 100644 (file)
--- a/includes/json/FormatJson.php
+++ b/includes/json/FormatJson.php
@@ -136,6 +136,11 @@ class FormatJson {
         * @return string|bool
         */
        private static function encode54( $value, $pretty, $escaping ) {
+               static $bug66021;
+               if ( $pretty !== false && $bug66021 === null ) {
+                       $bug66021 = json_encode( array(), JSON_PRETTY_PRINT ) !== '[]';
+               }
+
                // PHP escapes '/' to prevent breaking out of inline script blocks using '</script>',
                // which is hardly useful when '<' and '>' are escaped (and inadequate), and such
                // escaping negatively impacts the human readability of URLs and similar strings.
@@ -149,9 +154,11 @@ class FormatJson {
                }
 
                if ( $pretty !== false ) {
-                       // Remove whitespace inside empty arrays/objects; different JSON encoders
-                       // vary on this, and we want our output to be consistent across implementations.
-                       $json = preg_replace( self::WS_CLEANUP_REGEX, '', $json );
+                       // Workaround for <https://bugs.php.net/bug.php?id=66021>
+                       // Can be removed once we require PHP >= 5.4.28, 5.5.12, 5.6.0
+                       if ( $bug66021 ) {
+                               $json = preg_replace( self::WS_CLEANUP_REGEX, '', $json );
+                       }
                        if ( $pretty !== '    ' ) {
                                // Change the four-space indent to a tab indent
                                $json = str_replace( "\n    ", "\n\t", $json );