diff --git a/deps/lua/src/lua_cjson.c b/deps/lua/src/lua_cjson.c
index 991f5d31dd..b86d73e97c 100644
--- a/deps/lua/src/lua_cjson.c
+++ b/deps/lua/src/lua_cjson.c
@@ -464,9 +464,8 @@ static void json_encode_exception(lua_State *l, json_config_t *cfg, strbuf_t *js
 static void json_append_string(lua_State *l, strbuf_t *json, int lindex)
 {
     const char *escstr;
-    int i;
     const char *str;
-    size_t len;
+    size_t i, len;
 
     str = lua_tolstring(l, lindex, &len);
 
diff --git a/deps/lua/src/strbuf.c b/deps/lua/src/strbuf.c
index 775e8baf1b..97ee940c90 100644
--- a/deps/lua/src/strbuf.c
+++ b/deps/lua/src/strbuf.c
@@ -176,8 +176,7 @@ void strbuf_resize(strbuf_t *s, size_t len)
 
 void strbuf_append_string(strbuf_t *s, const char *str)
 {
-    int i;
-    size_t space;
+    size_t i, space;
 
     space = strbuf_empty_length(s);
 
diff --git a/tests/unit/scripting.tcl b/tests/unit/scripting.tcl
index a8195fb915..cedf2b4f7c 100644
--- a/tests/unit/scripting.tcl
+++ b/tests/unit/scripting.tcl
@@ -307,6 +307,13 @@ start_server {tags {"scripting"}} {
         set e
     } {*against a key*}
 
+    test {EVAL - JSON string encoding a string larger than 2GB} {
+        run_script {
+            local s = string.rep("a", 1024 * 1024 * 1024)
+            return #cjson.encode(s..s..s)
+        } 0
+    } {3221225474} {large-memory} ;# length includes two double quotes at both ends
+
     test {EVAL - JSON numeric decoding} {
         # We must return the table as a string because otherwise
         # Redis converts floats to ints and we get 0 and 1023 instead