Replacing a value now releases the memory

test/JsonVariant/to.cpp

@@ -0,0 +1,32 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <stdint.h>
+#include <catch.hpp>
+
+static const char* null = 0;
+
+TEST_CASE("JsonVariant::to<T>() releases string memory") {
+  DynamicJsonDocument doc;
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  variant.set(std::string("hello"));
+  REQUIRE(doc.memoryUsage() == JSON_STRING_SIZE(6));
+
+  SECTION("JsonVariant") {
+    variant.to<JsonVariant>();
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("JsonArray") {
+    variant.to<JsonArray>();
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("JsonObject") {
+    variant.to<JsonObject>();
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+}