Fix call of overloaded 'swap(...)' is ambiguous (fixes #1678)

CHANGELOG.md

@@ -12,6 +12,7 @@ HEAD
 * Add safe bool idiom in `JsonString`
 * Remove `DeserializationError == bool` and `DeserializationError != bool`
 * Fix `JsonVariant::memoryUsage()` for raw strings
+* Fix `call of overloaded 'swap(BasicJsonDocument&, BasicJsonDocument&)' is ambiguous` (issue #1678)
 
 v6.18.5 (2021-09-28)
 -------

extras/tests/JsonDocument/BasicJsonDocument.cpp

@@ -6,9 +6,9 @@
 #include <stdlib.h>  // malloc, free
 #include <catch.hpp>
 #include <sstream>
+#include <utility>
 
 using ARDUINOJSON_NAMESPACE::addPadding;
-using ARDUINOJSON_NAMESPACE::move;
 
 class SpyingAllocator {
  public:
@@ -78,7 +78,7 @@ TEST_CASE("BasicJsonDocument") {
       BasicJsonDocument<SpyingAllocator> doc1(4096, log);
       doc1.set(std::string("The size of this string is 32!!"));
 
-      BasicJsonDocument<SpyingAllocator> doc2(move(doc1));
+      BasicJsonDocument<SpyingAllocator> doc2(std::move(doc1));
 
       REQUIRE(doc2.as<std::string>() == "The size of this string is 32!!");
       REQUIRE(doc1.as<std::string>() == "null");
@@ -111,7 +111,7 @@ TEST_CASE("BasicJsonDocument") {
       doc1.set(std::string("The size of this string is 32!!"));
       BasicJsonDocument<SpyingAllocator> doc2(8, log);
 
-      doc2 = move(doc1);
+      doc2 = std::move(doc1);
 
       REQUIRE(doc2.as<std::string>() == "The size of this string is 32!!");
       REQUIRE(doc1.as<std::string>() == "null");

extras/tests/JsonDocument/CMakeLists.txt

@@ -19,6 +19,7 @@ add_executable(JsonDocumentTests
 	size.cpp
 	StaticJsonDocument.cpp
 	subscript.cpp
+	swap.cpp
 )
 
 add_test(JsonDocument JsonDocumentTests)

extras/tests/JsonDocument/swap.cpp

@@ -0,0 +1,13 @@
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+#include <utility>
+
+using namespace std;
+
+TEST_CASE("std::swap") {
+  SECTION("DynamicJsonDocument*") {
+    DynamicJsonDocument *p1, *p2;
+    swap(p1, p2);  // issue #1678
+  }
+}

src/ArduinoJson/MsgPack/endianess.hpp

@@ -5,25 +5,30 @@
 #pragma once
 
 #include <ArduinoJson/Polyfills/type_traits.hpp>
-#include <ArduinoJson/Polyfills/utility.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
 #if ARDUINOJSON_LITTLE_ENDIAN
+inline void swapBytes(uint8_t &a, uint8_t &b) {
+  uint8_t t(a);
+  a = b;
+  b = t;
+}
+
 inline void fixEndianess(uint8_t *p, integral_constant<size_t, 8>) {
-  swap(p[0], p[7]);
-  swap(p[1], p[6]);
-  swap(p[2], p[5]);
-  swap(p[3], p[4]);
+  swapBytes(p[0], p[7]);
+  swapBytes(p[1], p[6]);
+  swapBytes(p[2], p[5]);
+  swapBytes(p[3], p[4]);
 }
 
 inline void fixEndianess(uint8_t *p, integral_constant<size_t, 4>) {
-  swap(p[0], p[3]);
-  swap(p[1], p[2]);
+  swapBytes(p[0], p[3]);
+  swapBytes(p[1], p[2]);
 }
 
 inline void fixEndianess(uint8_t *p, integral_constant<size_t, 2>) {
-  swap(p[0], p[1]);
+  swapBytes(p[0], p[1]);
 }
 
 inline void fixEndianess(uint8_t *, integral_constant<size_t, 1>) {}

src/ArduinoJson/Polyfills/utility.hpp

@@ -1,28 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright Benoit Blanchon 2014-2021
-// MIT License
-
-#pragma once
-
-#include "type_traits.hpp"
-
-namespace ARDUINOJSON_NAMESPACE {
-template <typename T>
-inline void swap(T& a, T& b) {
-  T t(a);
-  a = b;
-  b = t;
-}
-
-#if ARDUINOJSON_HAS_RVALUE_REFERENCES
-template <typename T>
-typename remove_reference<T>::type&& move(T&& t) {
-  return static_cast<typename remove_reference<T>::type&&>(t);
-}
-#else
-template <typename T>
-T& move(T& t) {
-  return t;
-}
-#endif
-}  // namespace ARDUINOJSON_NAMESPACE