Fix global UDLs (#3646)

* Add ci_test_noglobaludls to CI

* Really default JSON_GLOBAL_UDLS to 1

* Test global UDLs

* Suppress warnings

* Clarify documentation

.github/workflows/ubuntu.yml

@@ -62,7 +62,7 @@ jobs:
     container: ghcr.io/nlohmann/json-ci:v2.4.0
     strategy:
       matrix:
-        target: [ci_test_diagnostics, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison]
+        target: [ci_test_diagnostics, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls]
     steps:
       - uses: actions/checkout@v3
       - name: cmake

cmake/ci.cmake

@@ -524,7 +524,8 @@ add_custom_target(ci_test_legacycomparison
 add_custom_target(ci_test_noglobaludls
     COMMAND CXX=${CLANG_TOOL} ${CMAKE_COMMAND}
     -DCMAKE_BUILD_TYPE=Debug -GNinja
-    -DJSON_BuildTests=ON -DJSON_FastTests=ON -DJSON_UseGlobalUDLs=OFF
+    -DJSON_BuildTests=ON -DJSON_FastTests=ON -DJSON_GlobalUDLs=OFF
+    -DCMAKE_CXX_FLAGS=-DJSON_TEST_NO_GLOBAL_UDLS
     -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_noglobaludls
     COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_noglobaludls
     COMMAND cd ${PROJECT_BINARY_DIR}/build_noglobaludls && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure

docs/mkdocs/docs/api/operator_literal_json.md

@@ -7,16 +7,17 @@ json operator "" _json(const char* s, std::size_t n);
 This operator implements a user-defined string literal for JSON objects. It can be used by adding `#!cpp _json` to a
 string literal and returns a [`json`](json.md) object if no parse error occurred.
 
-Use any of the following lines to bring the operator into scope:
+It is recommended to bring the operator into scope using any of the following lines:
 ```cpp
+using nlohmann::literals::operator "" _json;
 using namespace nlohmann::literals;
 using namespace nlohmann::json_literals;
 using namespace nlohmann::literals::json_literals;
 using namespace nlohmann;
 ```
+This is suggested to ease migration to the next major version release of the library.
+See ['JSON_USE_GLOBAL_UDLS`](macros/json_use_global_udls.md#notes) for details.
 
-Alternatively, define [`JSON_USE_GLOBAL_UDLS`](macros/json_use_global_udls.md) to make them available in the global
-namespace.
 ## Parameters
 
 `s` (in)

docs/mkdocs/docs/api/operator_literal_json_pointer.md

@@ -7,16 +7,17 @@ json_pointer operator "" _json_pointer(const char* s, std::size_t n);
 This operator implements a user-defined string literal for JSON Pointers. It can be used by adding `#!cpp _json_pointer`
 to a string literal and returns a [`json_pointer`](json_pointer/index.md) object if no parse error occurred.
 
-Use any of the following lines to bring the operator into scope:
+It is recommended to bring the operator into scope using any of the following lines:
 ```cpp
+using nlohmann::literals::operator "" _json_pointer;
 using namespace nlohmann::literals;
 using namespace nlohmann::json_literals;
 using namespace nlohmann::literals::json_literals;
 using namespace nlohmann;
 ```
+This is suggested to ease migration to the next major version release of the library.
+See ['JSON_USE_GLOBAL_UDLS`](macros/json_use_global_udls.md#notes) for details.
 
-Alternatively, define [`JSON_USE_GLOBAL_UDLS`](macros/json_use_global_udls.md) to make them available in the global
-namespace.
 ## Parameters
 
 `s` (in)

include/nlohmann/detail/macro_scope.hpp

@@ -464,5 +464,5 @@
 #endif
 
 #ifndef JSON_USE_GLOBAL_UDLS
-    #define JSON_USE_GLOBAL_UDLS 0
+    #define JSON_USE_GLOBAL_UDLS 1
 #endif

include/nlohmann/json.hpp

@@ -5154,7 +5154,8 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    using namespace nlohmann::literals::json_literals; // NOLINT(build/namespaces_literals)
+    using nlohmann::literals::json_literals::operator "" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    using nlohmann::literals::json_literals::operator "" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
 #endif
 
 #include <nlohmann/detail/macro_unscope.hpp>

single_include/nlohmann/json.hpp

@@ -2793,7 +2793,7 @@ JSON_HEDLEY_DIAGNOSTIC_POP
 #endif
 
 #ifndef JSON_USE_GLOBAL_UDLS
-    #define JSON_USE_GLOBAL_UDLS 0
+    #define JSON_USE_GLOBAL_UDLS 1
 #endif
 
 #if JSON_HAS_THREE_WAY_COMPARISON
@@ -24123,7 +24123,8 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    using namespace nlohmann::literals::json_literals; // NOLINT(build/namespaces_literals)
+    using nlohmann::literals::json_literals::operator "" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    using nlohmann::literals::json_literals::operator "" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
 #endif
 
 // #include <nlohmann/detail/macro_unscope.hpp>

tests/src/unit-class_parser.cpp

@@ -11,7 +11,9 @@
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <valarray>
 

tests/src/unit-deserialization.cpp

@@ -11,7 +11,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <iostream>
 #include <iterator>

tests/src/unit-element_access2.cpp

@@ -10,7 +10,9 @@
 #include "doctest_compatibility.h"
 
 #include <nlohmann/json.hpp>
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 TEST_CASE_TEMPLATE("element access 2", Json, nlohmann::json, nlohmann::ordered_json)
 {

tests/src/unit-json_patch.cpp

@@ -10,7 +10,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <fstream>
 #include "make_test_data_available.hpp"

tests/src/unit-json_pointer.cpp

@@ -11,7 +11,9 @@
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <sstream>
 

tests/src/unit-merge_patch.cpp

@@ -10,7 +10,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 TEST_CASE("JSON Merge Patch")
 {

tests/src/unit-msgpack.cpp

@@ -10,7 +10,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <fstream>
 #include <sstream>

tests/src/unit-readme.cpp

@@ -10,7 +10,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <deque>
 #include <forward_list>

tests/src/unit-regression1.cpp

@@ -14,7 +14,9 @@
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <fstream>
 #include <sstream>

tests/src/unit-regression2.cpp

@@ -22,7 +22,9 @@
 #include <nlohmann/json.hpp>
 using json = nlohmann::json;
 using ordered_json = nlohmann::ordered_json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <cstdio>
 #include <list>

tests/src/unit-udl.cpp

@@ -8,8 +8,6 @@
 
 #include "doctest_compatibility.h"
 
-#undef JSON_USE_GLOBAL_UDLS
-#define JSON_USE_GLOBAL_UDLS 0
 #include <nlohmann/json.hpp>
 
 TEST_CASE("user-defined string literals")
@@ -48,4 +46,12 @@ TEST_CASE("user-defined string literals")
         CHECK(R"({"foo": "bar", "baz": 42})"_json == j_expected);
         CHECK("/foo/bar"_json_pointer == ptr_expected);
     }
+
+#ifndef JSON_TEST_NO_GLOBAL_UDLS
+    SECTION("global namespace")
+    {
+        CHECK(R"({"foo": "bar", "baz": 42})"_json == j_expected);
+        CHECK("/foo/bar"_json_pointer == ptr_expected);
+    }
+#endif
 }

tests/src/unit-udt.cpp

@@ -14,7 +14,9 @@ DOCTEST_GCC_SUPPRESS_WARNING("-Wnoexcept")
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
-using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+    using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <map>
 #include <memory>