JsonObject::createNestedObject() returns JsonObject::invalid() if key is null (fixes #1891)

CHANGELOG.md

@@ -1,6 +1,11 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* `JsonObject::createNestedObject()` returns `JsonObject::invalid()` if key is null (issue #1891)
+
 v5.13.5
 -------
 

src/ArduinoJson/JsonObjectImpl.hpp

@@ -22,7 +22,9 @@ template <typename TStringRef>
 inline JsonObject &JsonObject::createNestedObject_impl(TStringRef key) {
   if (!_buffer) return JsonObject::invalid();
   JsonObject &object = _buffer->createObject();
-  set(key, object);
+  if (set(key, object))
     return object;
+  else
+    return JsonObject::invalid();
 }
 }  // namespace ArduinoJson

test/JsonObject/CMakeLists.txt

@@ -5,6 +5,7 @@
 add_executable(JsonObjectTests
 	basics.cpp
 	containsKey.cpp
+	createNestedObject.cpp
 	get.cpp
 	invalid.cpp
 	iterator.cpp

test/JsonObject/createNestedObject.cpp

@@ -0,0 +1,23 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2023
+// MIT License
+
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("JsonObject::createNestedObject()") {
+  DynamicJsonBuffer _jsonBuffer;
+  JsonObject& _object = _jsonBuffer.createObject();
+
+  SECTION("success() should return true if key is non-null") {
+    JsonObject& obj = _object.createNestedObject("key");
+    REQUIRE(obj.success() == true);
+  }
+
+  SECTION("success() should return false if key is null") {
+    const char* null = 0;
+    JsonObject& obj = _object.createNestedObject(null);
+    REQUIRE(obj.success() == false);
+  }
+}