From 020b51b46eceb1a8c2876aac263772ed55ba9a1a Mon Sep 17 00:00:00 2001
From: Xinchen Hui <laruence@php.net>
Date: Mon, 19 Jan 2015 01:04:23 -0500
Subject: [PATCH] Don't use >= as sorting condition

which could avoid breaking usage like:

usort($a, function($a, $b) { return $a > $b; })
---
 Zend/zend_sort.c                              | 13 +++++-----
 .../tests/array/usort_variation11.phpt        | 25 +++++++++++++++++++
 2 files changed, 31 insertions(+), 7 deletions(-)
 create mode 100644 ext/standard/tests/array/usort_variation11.phpt

diff --git a/Zend/zend_sort.c b/Zend/zend_sort.c
index 383fe226b4..78ed0ebb5f 100644
--- a/Zend/zend_sort.c
+++ b/Zend/zend_sort.c
@@ -91,10 +91,9 @@ ZEND_API void zend_qsort(void *base, size_t nmemb, size_t siz, compare_func_t co
 /* }}} */
 
 static inline void zend_sort_2(void *a, void *b, compare_func_t cmp, swap_func_t swp) /* {{{ */ {
-	if (cmp(a, b) <= 0) {
-		return;
+	if (cmp(a, b) > 0) {
+		swp(a, b);
 	}
-	swp(a, b);
 }
 /* }}} */
 
@@ -109,7 +108,7 @@ static inline void zend_sort_3(void *a, void *b, void *c, compare_func_t cmp, sw
 		}
 		return;
 	}
-	if (cmp(b, c) >= 0) {
+	if (cmp(c, b) <= 0) {
 		swp(a, c);
 		return;
 	}
@@ -215,7 +214,7 @@ ZEND_API void zend_insert_sort(void *base, size_t nmemb, size_t siz, compare_fun
 						}
 						if (j == start + siz) {
 							j -= siz;
-							if (cmp(j, i) < 0) {
+							if (cmp(i, j) > 0) {
 								j += siz;
 							}
 							break;
@@ -338,7 +337,7 @@ ZEND_API void zend_sort(void *base, size_t nmemb, size_t siz, compare_func_t cmp
 			i = pivot + siz;
 			j = end - siz;
 			while (1) {
-				while (cmp(i, pivot) < 0) {
+				while (cmp(pivot, i) > 0) {
 					i += siz;
 					if (UNEXPECTED(i == j)) {
 						goto done;
@@ -348,7 +347,7 @@ ZEND_API void zend_sort(void *base, size_t nmemb, size_t siz, compare_func_t cmp
 				if (UNEXPECTED(j == i)) {
 					goto done;
 				}
-				while (cmp(pivot, j) < 0) {
+				while (cmp(j, pivot) > 0) {
 					j -= siz;
 					if (UNEXPECTED(j == i)) {
 						goto done;
diff --git a/ext/standard/tests/array/usort_variation11.phpt b/ext/standard/tests/array/usort_variation11.phpt
new file mode 100644
index 0000000000..b6cdeef766
--- /dev/null
+++ b/ext/standard/tests/array/usort_variation11.phpt
@@ -0,0 +1,25 @@
+--TEST--
+Test usort() function : usage variations - binary return cmp
+--FILE--
+<?php
+
+function ucmp($a, $b) {
+	return $a > $b;
+}
+
+$range = array(2, 4, 8, 16, 32, 64, 128);
+
+foreach ($range as $r) {
+	$backup = $array = range(0, $r);
+	shuffle($array);
+	usort($array, "ucmp");
+	if ($array != $backup) {
+		var_dump($array);
+		var_dump($backup);
+		die("Whatever sorting algo you used, this test should never be broken");
+	}
+}
+echo "okey";
+?>
+--EXPECT--
+okey
-- 
2.40.0