LPUSHX and RPUSHX now return 0 size when key does not exist. (#1010)

Fixes #834 Signed-off-by: chakaz <chakaz@chakaz> Co-authored-by: chakaz <chakaz@chakaz>
dragonflydb · Mar 31, 2023 · a7d40f3 · a7d40f3
1 parent 5f41712
commit a7d40f3
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diff --git a/src/server/list_family.cc b/src/server/list_family.cc
@@ -437,7 +437,7 @@ OpResult<uint32_t> OpPush(const OpArgs& op_args, std::string_view key, ListDir d
   if (skip_notexist) {
     auto it_res = es->db_slice().Find(op_args.db_cntx, key, OBJ_LIST);
     if (!it_res)
-      return it_res.status();
+      return 0;  // Redis returns 0 for nonexisting keys for the *PUSHX actions.
     it = *it_res;
   } else {
     try {

diff --git a/src/server/list_family_test.cc b/src/server/list_family_test.cc
@@ -813,4 +813,28 @@ TEST_F(ListFamilyTest, BLMove) {
   ASSERT_THAT(resp.GetVec(), ElementsAre("val1", "val2"));
 }
 
+TEST_F(ListFamilyTest, LPushX) {
+  // No push for 'lpushx' on nonexisting key.
+  EXPECT_THAT(Run({"lpushx", kKey1, "val1"}), IntArg(0));
+  EXPECT_THAT(Run({"llen", kKey1}), IntArg(0));
+
+  EXPECT_THAT(Run({"lpush", kKey1, "val1"}), IntArg(1));
+  EXPECT_THAT(Run({"lrange", kKey1, "0", "-1"}), "val1");
+
+  EXPECT_THAT(Run({"lpushx", kKey1, "val2"}), IntArg(2));
+  EXPECT_THAT(Run({"lrange", kKey1, "0", "-1"}).GetVec(), ElementsAre("val2", "val1"));
+}
+
+TEST_F(ListFamilyTest, RPushX) {
+  // No push for 'rpushx' on nonexisting key.
+  EXPECT_THAT(Run({"rpushx", kKey1, "val1"}), IntArg(0));
+  EXPECT_THAT(Run({"llen", kKey1}), IntArg(0));
+
+  EXPECT_THAT(Run({"rpush", kKey1, "val1"}), IntArg(1));
+  EXPECT_THAT(Run({"lrange", kKey1, "0", "-1"}), "val1");
+
+  EXPECT_THAT(Run({"rpushx", kKey1, "val2"}), IntArg(2));
+  EXPECT_THAT(Run({"lrange", kKey1, "0", "-1"}).GetVec(), ElementsAre("val1", "val2"));
+}
+
 }  // namespace dfly