diff --git a/src/cluster.c b/src/cluster.c
index 07cb435..31afae2 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -202,14 +202,12 @@ static void valkeyClusterSetError(valkeyClusterContext *cc, int type,
                                   const char *str) {
     cc->err = type;
 
-    /* Copy error string when possible. */
+    assert(str != NULL);
     if (str != NULL && str != cc->errstr) {
         size_t len = strlen(str);
         len = len < (sizeof(cc->errstr) - 1) ? len : (sizeof(cc->errstr) - 1);
         memcpy(cc->errstr, str, len);
         cc->errstr[len] = '\0';
-    } else if (str == NULL) { /* No known usecase. Clear previous errstr. */
-        cc->errstr[0] = '\0';
     }
 }
 
@@ -2778,14 +2776,12 @@ static void valkeyClusterAsyncSetError(valkeyClusterAsyncContext *acc, int type,
     valkeyClusterSetError(acc->cc, type, str); /* Keep error flags identical. */
     acc->err = type;
 
-    /* Copy error string when possible. */
+    assert(str != NULL);
     if (str != NULL && str != acc->errstr) {
         size_t len = strlen(str);
         len = len < (sizeof(acc->errstr) - 1) ? len : (sizeof(acc->errstr) - 1);
         memcpy(acc->errstr, str, len);
         acc->errstr[len] = '\0';
-    } else if (str == NULL) { /* No known usecase. Clear previous errstr. */
-        acc->errstr[0] = '\0';
     }
 }