Fix crash in RM_ScanKey() when used with hexpire (#13320)

RM_ScanKey() was overlooked while introducing hash field expiration. 
An assert is triggered when it is called on a hash key with
OBJ_ENCODING_LISTPACK_EX encoding.

I've changed to code to handle listpackex encoding properly.

src/module.c

@@ -11188,22 +11188,32 @@ int RM_ScanKey(RedisModuleKey *key, RedisModuleScanCursor *cursor, RedisModuleSc
         cursor->done = 1;
         ret = 0;
     } else if (o->type == OBJ_ZSET || o->type == OBJ_HASH) {
-        unsigned char *p = lpSeek(o->ptr,0);
+        unsigned char *lp, *p;
         unsigned char *vstr;
         unsigned int vlen;
         long long vll;
+
+        if (o->type == OBJ_HASH)
+            lp = hashTypeListpackGetLp(o);
+        else
+            lp = o->ptr;
+
+        p = lpSeek(lp,0);
         while(p) {
             vstr = lpGetValue(p,&vlen,&vll);
             robj *field = (vstr != NULL) ?
                 createStringObject((char*)vstr,vlen) :
                 createStringObjectFromLongLongWithSds(vll);
-            p = lpNext(o->ptr,p);
+            p = lpNext(lp,p);
             vstr = lpGetValue(p,&vlen,&vll);
             robj *value = (vstr != NULL) ?
                 createStringObject((char*)vstr,vlen) :
                 createStringObjectFromLongLongWithSds(vll);
             fn(key, field, value, privdata);
-            p = lpNext(o->ptr,p);
+            p = lpNext(lp,p);
+            if (o->type == OBJ_HASH && o->encoding == OBJ_ENCODING_LISTPACK_EX)
+                p = lpNext(lp, p); /* Skip expire time */
+
             decrRefCount(field);
             decrRefCount(value);
         }

tests/unit/moduleapi/scan.tcl

@@ -24,6 +24,14 @@ start_server {tags {"modules"}} {
         lsort [r scan.scan_key hh1]
     } {{f1 1}}
 
+    test {Module scan hash listpack with hexpire} {
+        r hmset hh f1 v1 f2 v2
+        r hexpire hh 100000 fields 1 f1
+        assert_range [r httl hh fields 1 f1] 10000 100000
+        assert_encoding listpackex hh
+        lsort [r scan.scan_key hh]
+    } {{f1 v1} {f2 v2}}
+
     test {Module scan hash dict} {
         r config set hash-max-ziplist-entries 2
         r hmset hh f3 v3
@@ -31,6 +39,16 @@ start_server {tags {"modules"}} {
         lsort [r scan.scan_key hh]
     } {{f1 v1} {f2 v2} {f3 v3}}
 
+    test {Module scan hash dict with hexpire} {
+        r config set hash-max-listpack-entries 1
+        r del hh
+        r hmset hh f1 v1 f2 v2 f3 v3
+        r hexpire hh 100000 fields 1 f2
+        assert_range [r httl hh fields 1 f2] 10000 100000
+        assert_encoding hashtable hh
+        lsort [r scan.scan_key hh]
+    } {{f1 v1} {f2 v2} {f3 v3}}
+
     test {Module scan zset listpack} {
         r zadd zz 1 f1 2 f2
         assert_encoding listpack zz