From: Pieter Noordhuis <pcnoordhuis@gmail.com>
Date: Thu, 4 Mar 2010 00:33:37 +0000 (+0100)
Subject: fix ZRANK (realize that rank is 1-based due to the skip list header)
X-Git-Url: https://git.saurik.com/redis.git/commitdiff_plain/67cac14343260a225ba8a68f2d3c503c95a2f4ae

fix ZRANK (realize that rank is 1-based due to the skip list header)
---

diff --git a/redis.c b/redis.c
index 8f524dd6..6ad439b0 100644
--- a/redis.c
+++ b/redis.c
@@ -5483,13 +5483,16 @@ static void zrankCommand(redisClient *c) {
         while (x->forward[i] &&
             (x->forward[i]->score < *score ||
                 (x->forward[i]->score == *score &&
-                compareStringObjects(x->forward[i]->obj,c->argv[2]) < 0))) {
+                compareStringObjects(x->forward[i]->obj,c->argv[2]) <= 0))) {
             rank += x->span[i];
             x = x->forward[i];
         }
 
-        if (x->forward[i] && compareStringObjects(x->forward[i]->obj,c->argv[2]) == 0) {
-            addReplyLong(c, rank);
+        /* x might be equal to zsl->header, so test if obj is non-NULL */
+        if (x->obj && compareStringObjects(x->obj,c->argv[2]) == 0) {
+            /* the pointer from zsl->header to the first element also spans one,
+             * which makes the rank 1-based */
+            addReplyLong(c, rank-1);
             return;
         }
     }
diff --git a/test-redis.tcl b/test-redis.tcl
index 4ec3830e..0fc1e7df 100644
--- a/test-redis.tcl
+++ b/test-redis.tcl
@@ -1545,7 +1545,7 @@ proc main {server port} {
                 set ele [lindex [$r zrange myzset $index $index] 0]
                 set rank [$r zrank myzset $ele]
                 if {$rank != $index} {
-                    set err "$ele RANK is wrong! ($rank != [expr $index+1])"
+                    set err "$ele RANK is wrong! ($rank != $index)"
                     break
                 }
             }