chore(server): Sort correctly in ZINTER (#3566)

dragonflydb · Aug 25, 2024 · fce7970 · fce7970
1 parent 20b8817
commit fce7970
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/src/server/zset_family.cc b/src/server/zset_family.cc
@@ -2123,7 +2123,7 @@ void ZSetFamily::ZInter(CmdArgList args, ConnectionContext* cntx) {
 
   std::sort(scored_array.begin(), scored_array.end(),
             [](const std::pair<std::string, double>& a, const std::pair<std::string, double>& b) {
-              return a.second < b.second;
+              return tie(a.second, a.first) < tie(b.second, b.first);
             });
 
   auto* rb = static_cast<RedisReplyBuilder*>(cntx->reply_builder());

diff --git a/src/server/zset_family_test.cc b/src/server/zset_family_test.cc
@@ -675,6 +675,14 @@ TEST_F(ZSetFamilyTest, ZInter) {
 
   resp = Run({"zinter", "3", "z3", "z4", "z5"});
   EXPECT_THAT(resp, ArrLen(0));
+
+  // zinter output sorts keys with equal scores lexicographically
+  Run({"del", "z1", "z2", "z3", "z4", "z5"});
+  Run({"zadd", "z1", "1", "e", "1", "a", "1", "b", "1", "x"});
+  Run({"zadd", "z2", "1", "e", "1", "a", "1", "b", "1", "y"});
+  Run({"zadd", "z3", "1", "e", "1", "a", "1", "b", "1", "z"});
+  Run({"zadd", "z4", "1", "e", "1", "a", "1", "b", "1", "o"});
+  EXPECT_THAT(Run({"zinter", "4", "z1", "z2", "z3", "z4"}).GetVec(), ElementsAre("a", "b", "e"));
 }
 
 TEST_F(ZSetFamilyTest, ZInterCard) {