From 072ce42b5fdc2dea7cacd7e6a905893248a842ad Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aaron@users.mediawiki.org>
Date: Sun, 26 Jun 2011 04:50:24 +0000
Subject: [PATCH] Made '^' (XOR) in recCheckCondition() act as a one-hot
 detector. Before r28805, XOR silently ignored subconds beyond the first two.
 After r28805, XOR passed iff an odd number of subconds passed. It now passes
 iff exactly one subcond passes. This should be more intuitive, as I highly
 doubt anyone using 3+ subconds was doing it correctly before.

---
 includes/Autopromote.php | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/includes/Autopromote.php b/includes/Autopromote.php
index bdb2cb066c..2a869edb11 100644
--- a/includes/Autopromote.php
+++ b/includes/Autopromote.php
@@ -87,7 +87,7 @@ class Autopromote {
 
 		if ( is_array( $cond ) && count( $cond ) >= 2 && in_array( $cond[0], $validOps ) ) {
 			# Recursive condition
-			if ( $cond[0] == '&' ) {
+			if ( $cond[0] == '&' ) { // AND (all conds pass)
 				foreach ( array_slice( $cond, 1 ) as $subcond ) {
 					if ( !self::recCheckCondition( $subcond, $user ) ) {
 						return false;
@@ -95,7 +95,7 @@ class Autopromote {
 				}
 
 				return true;
-			} elseif ( $cond[0] == '|' ) {
+			} elseif ( $cond[0] == '|' ) { // OR (at least one cond passes)
 				foreach ( array_slice( $cond, 1 ) as $subcond ) {
 					if ( self::recCheckCondition( $subcond, $user ) ) {
 						return true;
@@ -103,18 +103,20 @@ class Autopromote {
 				}
 
 				return false;
-			} elseif ( $cond[0] == '^' ) {
-				$res = null;
+			} elseif ( $cond[0] == '^' ) { // XOR (exactly one cond passes)
+				$res = false;
 				foreach ( array_slice( $cond, 1 ) as $subcond ) {
-					if ( is_null( $res ) ) {
-						$res = self::recCheckCondition( $subcond, $user );
-					} else {
-						$res = ( $res xor self::recCheckCondition( $subcond, $user ) );
+					if ( self::recCheckCondition( $subcond, $user ) ) {
+						if ( $res ) {
+							return false;
+						} else {
+							$res = true;
+						}
 					}
 				}
 
 				return $res;
-			} elseif ( $cond[0] == '!' ) {
+			} elseif ( $cond[0] == '!' ) { // NOT (no conds pass)
 				foreach ( array_slice( $cond, 1 ) as $subcond ) {
 					if ( self::recCheckCondition( $subcond, $user ) ) {
 						return false;
-- 
2.20.1