From e53ca04b50b86ef158a75c54ae9ee8b17e31719c Mon Sep 17 00:00:00 2001
From: Pieter Noordhuis <pcnoordhuis@gmail.com>
Date: Fri, 11 Mar 2011 18:17:53 +0100
Subject: [PATCH] Test for empty inner range when looking for elements in range

---
 src/t_zset.c             | 32 ++++++++++++++++++++++----------
 tests/unit/type/zset.tcl |  6 ++++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/src/t_zset.c b/src/t_zset.c
index 65c99622..b8a961eb 100644
--- a/src/t_zset.c
+++ b/src/t_zset.c
@@ -226,10 +226,12 @@ zskiplistNode *zslFirstInRange(zskiplist *zsl, zrangespec range) {
                 x = x->level[i].forward;
     }
 
-    /* The tail is in range, so the previous block should always return a
-     * node that is non-NULL and the last one to be out of range. */
+    /* This is an inner range, so the next node cannot be NULL. */
     x = x->level[0].forward;
-    redisAssert(x != NULL && zslValueInRange(x->score,&range));
+    redisAssert(x != NULL);
+
+    /* Check if score <= max. */
+    if (!zslValueLteMax(x->score,&range)) return NULL;
     return x;
 }
 
@@ -250,9 +252,11 @@ zskiplistNode *zslLastInRange(zskiplist *zsl, zrangespec range) {
                 x = x->level[i].forward;
     }
 
-    /* The header is in range, so the previous block should always return a
-     * node that is non-NULL and in range. */
-    redisAssert(x != NULL && zslValueInRange(x->score,&range));
+    /* This is an inner range, so this node cannot be NULL. */
+    redisAssert(x != NULL);
+
+    /* Check if score >= min. */
+    if (!zslValueGteMin(x->score,&range)) return NULL;
     return x;
 }
 
@@ -531,8 +535,12 @@ unsigned char *zzlFirstInRange(unsigned char *zl, zrangespec range) {
         redisAssert(sptr != NULL);
 
         score = zzlGetScore(sptr);
-        if (zslValueGteMin(score,&range))
-            return eptr;
+        if (zslValueGteMin(score,&range)) {
+            /* Check if score <= max. */
+            if (zslValueLteMax(score,&range))
+                return eptr;
+            return NULL;
+        }
 
         /* Move to next element. */
         eptr = ziplistNext(zl,sptr);
@@ -555,8 +563,12 @@ unsigned char *zzlLastInRange(unsigned char *zl, zrangespec range) {
         redisAssert(sptr != NULL);
 
         score = zzlGetScore(sptr);
-        if (zslValueLteMax(score,&range))
-            return eptr;
+        if (zslValueLteMax(score,&range)) {
+            /* Check if score >= min. */
+            if (zslValueGteMin(score,&range))
+                return eptr;
+            return NULL;
+        }
 
         /* Move to previous element by moving to the score of previous element.
          * When this returns NULL, we know there also is no element. */
diff --git a/tests/unit/type/zset.tcl b/tests/unit/type/zset.tcl
index fdeebd2f..6218a95c 100644
--- a/tests/unit/type/zset.tcl
+++ b/tests/unit/type/zset.tcl
@@ -247,6 +247,12 @@ start_server {tags {"zset"}} {
         assert_equal {} [r zrangebyscore zset (-inf (-6]
         assert_equal {} [r zrevrangebyscore zset (+inf (6]
         assert_equal {} [r zrevrangebyscore zset (-6 (-inf]
+
+        # empty inner range
+        assert_equal {} [r zrangebyscore zset 2.4 2.6]
+        assert_equal {} [r zrangebyscore zset (2.4 2.6]
+        assert_equal {} [r zrangebyscore zset 2.4 (2.6]
+        assert_equal {} [r zrangebyscore zset (2.4 (2.6]
     }
 
     test "ZRANGEBYSCORE with WITHSCORES" {