HSETEX: Support NX/XX Flags (#2668)

### Summary
Addresses #2619.  
This PR extends the `HSETEX` command to support optional key-level `NX`
and `XX` flags, allowing operations conditional on the existence of the
hash key.

### Changes
- Updated `hsetex.json` and regenerated `commands.def`.
- Extended argument parsing for NX/XX.
- Added key-level `NX`/`XX` support in `HSETEX`.
- Added tests covering all four NX/XX scenarios.

---------

Signed-off-by: Hanxi Zhang <[email protected]>
Co-authored-by: Ran Shidlansik <[email protected]>

Author: hanxizh9910

src/commands.def

@@ -4312,6 +4312,12 @@ keySpec HSETEX_Keyspecs[1] = {
 };
 #endif
 
+/* HSETEX key_condition argument table */
+struct COMMAND_ARG HSETEX_key_condition_Subargs[] = {
+{MAKE_ARG("nx",ARG_TYPE_PURE_TOKEN,-1,"NX",NULL,NULL,CMD_ARG_NONE,0,NULL)},
+{MAKE_ARG("xx",ARG_TYPE_PURE_TOKEN,-1,"XX",NULL,NULL,CMD_ARG_NONE,0,NULL)},
+};
+
 /* HSETEX fields_condition argument table */
 struct COMMAND_ARG HSETEX_fields_condition_Subargs[] = {
 {MAKE_ARG("fnx",ARG_TYPE_PURE_TOKEN,-1,"FNX",NULL,NULL,CMD_ARG_NONE,0,NULL)},
@@ -4342,6 +4348,7 @@ struct COMMAND_ARG HSETEX_fields_Subargs[] = {
 /* HSETEX argument table */
 struct COMMAND_ARG HSETEX_Args[] = {
 {MAKE_ARG("key",ARG_TYPE_KEY,0,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
+{MAKE_ARG("key-condition",ARG_TYPE_ONEOF,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,2,NULL),.subargs=HSETEX_key_condition_Subargs},
 {MAKE_ARG("fields-condition",ARG_TYPE_ONEOF,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,2,NULL),.subargs=HSETEX_fields_condition_Subargs},
 {MAKE_ARG("expiration",ARG_TYPE_ONEOF,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,5,NULL),.subargs=HSETEX_expiration_Subargs},
 {MAKE_ARG("fields",ARG_TYPE_BLOCK,-1,"FIELDS",NULL,NULL,CMD_ARG_NONE,2,NULL),.subargs=HSETEX_fields_Subargs},
@@ -11808,7 +11815,7 @@ struct COMMAND_STRUCT serverCommandTable[] = {
 {MAKE_CMD("hrandfield","Returns one or more random fields from a hash.","O(N) where N is the number of fields returned","6.2.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HRANDFIELD_History,0,HRANDFIELD_Tips,1,hrandfieldCommand,-2,CMD_READONLY,ACL_CATEGORY_HASH,HRANDFIELD_Keyspecs,1,NULL,2),.args=HRANDFIELD_Args},
 {MAKE_CMD("hscan","Iterates over fields and values of a hash.","O(1) for every call. O(N) for a complete iteration, including enough command calls for the cursor to return back to 0. N is the number of elements inside the collection.","2.8.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSCAN_History,0,HSCAN_Tips,1,hscanCommand,-3,CMD_READONLY,ACL_CATEGORY_HASH,HSCAN_Keyspecs,1,NULL,5),.args=HSCAN_Args},
 {MAKE_CMD("hset","Creates or modifies the value of a field in a hash.","O(1) for each field/value pair added, so O(N) to add N field/value pairs when the command is called with multiple field/value pairs.","2.0.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSET_History,1,HSET_Tips,0,hsetCommand,-4,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_HASH,HSET_Keyspecs,1,NULL,2),.args=HSET_Args},
-{MAKE_CMD("hsetex","Set the value of one or more fields of a given hash key, and optionally set their expiration time.","O(1)","9.0.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSETEX_History,0,HSETEX_Tips,0,hsetexCommand,-6,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_HASH,HSETEX_Keyspecs,1,NULL,4),.args=HSETEX_Args},
+{MAKE_CMD("hsetex","Set the value of one or more fields of a given hash key, and optionally set their expiration time.","O(1)","9.0.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSETEX_History,0,HSETEX_Tips,0,hsetexCommand,-6,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_HASH,HSETEX_Keyspecs,1,NULL,5),.args=HSETEX_Args},
 {MAKE_CMD("hsetnx","Sets the value of a field in a hash only when the field doesn't exist.","O(1)","2.0.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSETNX_History,0,HSETNX_Tips,0,hsetnxCommand,4,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_HASH,HSETNX_Keyspecs,1,NULL,3),.args=HSETNX_Args},
 {MAKE_CMD("hstrlen","Returns the length of the value of a field.","O(1)","3.2.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HSTRLEN_History,0,HSTRLEN_Tips,0,hstrlenCommand,3,CMD_READONLY|CMD_FAST,ACL_CATEGORY_HASH,HSTRLEN_Keyspecs,1,NULL,2),.args=HSTRLEN_Args},
 {MAKE_CMD("httl","Returns the remaining time to live (in seconds) of a hash key's field(s) that have an associated expiration.","O(1) for each field, so O(N) for N items when the command is called with multiple fields.","9.0.0",CMD_DOC_NONE,NULL,NULL,"hash",COMMAND_GROUP_HASH,HTTL_History,0,HTTL_Tips,0,httlCommand,-5,CMD_READONLY|CMD_FAST,ACL_CATEGORY_HASH,HTTL_Keyspecs,1,NULL,2),.args=HTTL_Args},

src/commands/hsetex.json

@@ -52,6 +52,23 @@
                 "type": "key",
                 "key_spec_index": 0
             },
+            {
+                "name": "key-condition",
+                "type": "oneof",
+                "optional": true,
+                "arguments": [
+                    {
+                        "name": "nx",
+                        "type": "pure-token",
+                        "token": "NX"
+                    },
+                    {
+                        "name": "xx",
+                        "type": "pure-token",
+                        "token": "XX"
+                    }
+                ]
+            },
             {
                 "name": "fields-condition",
                 "type": "oneof",

src/server.c

@@ -7524,12 +7524,12 @@ int parseExtendedCommandArgumentsOrReply(client *c, int *flags, int *unit, robj
         /* clang-format off */
         if ((opt[0] == 'n' || opt[0] == 'N') &&
             (opt[1] == 'x' || opt[1] == 'X') && opt[2] == '\0' &&
-            !(*flags & ARGS_SET_XX || *flags & ARGS_SET_IFEQ) && (command_type == COMMAND_SET))
+            !(*flags & ARGS_SET_XX || *flags & ARGS_SET_IFEQ) && (command_type == COMMAND_SET || command_type == COMMAND_HSET))
         {
             *flags |= ARGS_SET_NX;
         } else if ((opt[0] == 'x' || opt[0] == 'X') &&
                    (opt[1] == 'x' || opt[1] == 'X') && opt[2] == '\0' &&
-                   !(*flags & ARGS_SET_NX || *flags & ARGS_SET_IFEQ) && (command_type == COMMAND_SET))
+                   !(*flags & ARGS_SET_NX || *flags & ARGS_SET_IFEQ) && (command_type == COMMAND_SET || command_type == COMMAND_HSET))
         {
             *flags |= ARGS_SET_XX;
         } else if ((opt[0] == 'f' || opt[0] == 'F') &&

src/t_hash.c

@@ -1190,6 +1190,7 @@ void hsetexCommand(client *c) {
     int changes = 0;
     robj **new_argv = NULL;
     int new_argc = 0;
+    int need_rewrite_argv = 0;
 
     for (; fields_index < c->argc - 1; fields_index++) {
         if (!strcasecmp(c->argv[fields_index]->ptr, "fields")) {
@@ -1209,6 +1210,17 @@ void hsetexCommand(client *c) {
     if (checkType(c, o, OBJ_HASH))
         return;
 
+    if (flags & (ARGS_SET_NX | ARGS_SET_XX | ARGS_SET_FNX | ARGS_SET_FXX | ARGS_EX | ARGS_PX | ARGS_EXAT)) {
+        need_rewrite_argv = 1;
+    }
+
+    /* Check NX/XX key-level conditions before creating a new object */
+    if (((flags & ARGS_SET_NX) && o != NULL) ||
+        ((flags & ARGS_SET_XX) && o == NULL)) {
+        addReply(c, shared.czero);
+        return;
+    }
+
     /* Handle parsing and calculating the expiration time. */
     if (flags & ARGS_KEEPTTL)
         set_flags |= HASH_SET_KEEP_EXPIRY;
@@ -1252,13 +1264,37 @@ void hsetexCommand(client *c) {
 
     bool has_volatile_fields = hashTypeHasVolatileFields(o);
 
-    /* In case we are expiring all the elements prepare a new argv since we are going to delete all the expired fields. */
+    /* Prepare a new argv when rewriting the command. If set_expired is true,
+     * all expired fields will be deleted. Otherwise, if rewriting is needed due to NX/XX/FNX/FXX flags,
+     * copy the command, key, and optional arguments, skipping the NX/XX/FNX/FXX flags. */
     if (set_expired) {
         new_argv = zmalloc(sizeof(robj *) * (num_fields + 2));
         new_argv[new_argc++] = shared.hdel;
         incrRefCount(shared.hdel);
         new_argv[new_argc++] = c->argv[1];
         incrRefCount(c->argv[1]);
+    } else if (need_rewrite_argv) {
+        /* We use new_argv for rewrite */
+        new_argv = zmalloc(sizeof(robj *) * c->argc);
+        // Copy optional args (skip NX/XX/FNX/FXX)
+        for (int i = 0; i < fields_index; i++) {
+            if (strcmp(c->argv[i]->ptr, "NX") &&
+                strcmp(c->argv[i]->ptr, "XX") &&
+                strcmp(c->argv[i]->ptr, "FNX") &&
+                strcmp(c->argv[i]->ptr, "FXX")) {
+                /* Propagate as HSETEX Key Value PXAT millisecond-timestamp if there is
+                 * EX/PX/EXAT flag. */
+                if (expire && !(flags & ARGS_PXAT) && c->argv[i + 1] == expire) {
+                    robj *milliseconds_obj = createStringObjectFromLongLong(when);
+                    new_argv[new_argc++] = shared.pxat;
+                    new_argv[new_argc++] = milliseconds_obj;
+                    i++; // skip the original expire argument
+                } else {
+                    new_argv[new_argc++] = c->argv[i];
+                    incrRefCount(c->argv[i]);
+                }
+            }
+        }
     }
 
     for (i = fields_index; i < c->argc; i += 2) {
@@ -1273,6 +1309,12 @@ void hsetexCommand(client *c) {
         } else {
             hashTypeSet(o, c->argv[i]->ptr, c->argv[i + 1]->ptr, when, set_flags);
             changes++;
+            if (need_rewrite_argv) {
+                new_argv[new_argc++] = c->argv[i];
+                incrRefCount(c->argv[i]);
+                new_argv[new_argc++] = c->argv[i + 1];
+                incrRefCount(c->argv[i + 1]);
+            }
         }
     }
 
@@ -1287,20 +1329,10 @@ void hsetexCommand(client *c) {
             notifyKeyspaceEvent(NOTIFY_HASH, "hexpired", c->argv[1], c->db->id);
         } else {
             notifyKeyspaceEvent(NOTIFY_HASH, "hset", c->argv[1], c->db->id);
+            if (need_rewrite_argv) {
+                replaceClientCommandVector(c, new_argc, new_argv);
+            }
             if (expire) {
-                /* Propagate as HSETEX Key Value PXAT millisecond-timestamp if there is
-                 * EX/PX/EXAT flag. */
-                if (!(flags & ARGS_PXAT)) {
-                    for (int i = 2; i < fields_index; i++) {
-                        if (c->argv[i + 1] == expire) {
-                            robj *milliseconds_obj = createStringObjectFromLongLong(when);
-                            rewriteClientCommandArgument(c, i, shared.pxat);
-                            rewriteClientCommandArgument(c, i + 1, milliseconds_obj);
-                            decrRefCount(milliseconds_obj);
-                            break;
-                        }
-                    }
-                }
                 notifyKeyspaceEvent(NOTIFY_HASH, "hexpire", c->argv[1], c->db->id);
             }
         }

tests/unit/hashexpire.tcl

@@ -627,7 +627,43 @@ start_server {tags {"hashexpire"}} {
          assert_error {ERR numfields should be greater than 0 and match the provided number of fields} {r HSETEX myhash PX 100 FIELDS 1 field1 val1 extra}
     } 
 
+    ## NX/XX key-level tests
 
+    test {HSETEX NX - non-existing key creates the key} {
+        r FLUSHALL
+        set res [r HSETEX myhash NX FIELDS 2 f1 v1 f2 v2]
+        assert_equal 1 $res
+        assert_equal v1 [r HGET myhash f1]
+        assert_equal v2 [r HGET myhash f2]
+    }
+
+    test {HSETEX NX - existing key blocked} {
+        r FLUSHALL
+        r HSET myhash f1 v1
+        set res [r HSETEX myhash NX FIELDS 2 f1 new1 f2 new2]
+        assert_equal 0 $res
+        assert_equal v1 [r HGET myhash f1]
+        assert_equal 0 [r HEXISTS myhash f2]
+    }
+
+    test {HSETEX XX - existing key updates fields} {
+        r FLUSHALL
+        r HSET myhash f1 v1 f2 v2
+        set res [r HSETEX myhash XX FIELDS 2 f1 new1 f2 new2]
+        assert_equal 1 $res
+        assert_equal new1 [r HGET myhash f1]
+        assert_equal new2 [r HGET myhash f2]
+    }
+
+    test {HSETEX XX - non-existing key blocked} {
+        r FLUSHALL
+        set res [r HSETEX myhash XX FIELDS 2 f1 v1 f2 v2]
+        assert_equal 0 $res
+        assert_equal 0 [r EXISTS myhash]
+        assert_equal 0 [r HEXISTS myhash f1]
+        assert_equal 0 [r HEXISTS myhash f2]
+    }
+    
     ## FNX/FXX
 
     # hsetex throws ERR *, it shouldn't
@@ -690,6 +726,65 @@ start_server {tags {"hashexpire"}} {
         assert_equal 0 [r EXISTS myhash]
     }
 
+    ## NX/XX + FNX/FXX combinations
+
+    # NX + FNX — only set if key does not exist AND fields do not exist
+    test {HSETEX EX NX FNX - set only if key missing and fields missing} {
+        r FLUSHALL
+        set res [r HSETEX myhash EX 10 NX FNX FIELDS 2 f1 v1 f2 v2]
+        assert_equal 1 $res
+        assert_equal v1 [r HGET myhash f1]
+        assert_equal v2 [r HGET myhash f2]
+
+        # Try again — key exists now, should block
+        set res [r HSETEX myhash EX 10 NX FNX FIELDS 2 f3 v3 f4 v4]
+        assert_equal 0 $res
+        assert_equal 0 [r HEXISTS myhash f3]
+        assert_equal 0 [r HEXISTS myhash f4]
+    }
+
+    # NX + FXX — only set if key does not exist AND all fields exist (key missing → blocked)
+    test {HSETEX EX NX FXX - key missing blocks all} {
+        r FLUSHALL
+        set res [r HSETEX myhash EX 10 NX FXX FIELDS 2 f1 v1 f2 v2]
+        assert_equal 0 $res
+        assert_equal 0 [r EXISTS myhash]
+        assert_equal 0 [r HEXISTS myhash f1]
+        assert_equal 0 [r HEXISTS myhash f2]
+    }
+
+    # XX + FNX — only set if key exists AND none of the fields exist
+    test {HSETEX EX XX FNX - set only if key exists and fields missing} {
+        r FLUSHALL
+        r HSET myhash f1 old1
+        set res [r HSETEX myhash EX 10 XX FNX FIELDS 2 f2 v2 f3 v3]
+        assert_equal 1 $res
+        assert_equal v2 [r HGET myhash f2]
+        assert_equal v3 [r HGET myhash f3]
+
+        # Try again — fields already exist → should block
+        set res [r HSETEX myhash EX 10 XX FNX FIELDS 2 f2 x f4 y]
+        assert_equal 0 $res
+        assert_equal v2 [r HGET myhash f2]
+        assert_equal 0 [r HEXISTS myhash f4]
+    }
+
+    # XX + FXX — only set if key exists AND all fields exist
+    test {HSETEX EX XX FXX - set only if key exists and all fields exist} {
+        r FLUSHALL
+        r HSET myhash f1 old1 f2 old2
+        set res [r HSETEX myhash EX 10 XX FXX FIELDS 2 f1 new1 f2 new2]
+        assert_equal 1 $res
+        assert_equal new1 [r HGET myhash f1]
+        assert_equal new2 [r HGET myhash f2]
+
+        # Try when one field is missing → should block
+        set res [r HSETEX myhash EX 10 XX FXX FIELDS 2 f1 x f3 y]
+        assert_equal 0 $res
+        assert_equal new1 [r HGET myhash f1]
+        assert_equal 0 [r HEXISTS myhash f3]
+    }
+
     ###### Test EXPIRE #############