From f3768d686841e0417f7ca09f0d98d58e08ad7e0b Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Thu, 24 Sep 2026 17:01:19 +0200
Subject: [PATCH] Match ABI tag order in namespace tests to abi_macros.hpp
 (#5551)

* Match ABI tag order in namespace tests to abi_macros.hpp

NLOHMANN_JSON_ABI_TAGS concatenates the tags as _diag, _ldvcmp, _dp,
but the default and noversion ABI tests expected _diag, _dp, _ldvcmp.
The tests therefore failed whenever both JSON_DIAGNOSTIC_POSITIONS and
JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON were enabled, a combination
CI never exercises. Reorder the expectations to match the header.

Also document the _dp tag in the namespace feature page, which listed
only _diag and _ldvcmp.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test the ABI namespace with all ABI tags enabled

Build the default and noversion ABI config tests a second time with
JSON_DIAGNOSTICS, JSON_DIAGNOSTIC_POSITIONS and
JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON all set, so the expected tag
order is checked on every test run instead of depending on which CMake
options a CI job happens to enable.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 docs/mkdocs/docs/features/namespace.md |  1 +
 tests/abi/config/CMakeLists.txt        | 14 ++++++++++++++
 tests/abi/config/default.cpp           |  8 ++++----
 tests/abi/config/noversion.cpp         |  8 ++++----
 4 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/docs/mkdocs/docs/features/namespace.md b/docs/mkdocs/docs/features/namespace.md
index 5542c1f88..c4efe772a 100644
--- a/docs/mkdocs/docs/features/namespace.md
+++ b/docs/mkdocs/docs/features/namespace.md
@@ -15,6 +15,7 @@ The complete default namespace name is derived as follows:
     - [`JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md) defined non-zero appends `_diag`.
     - [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../api/macros/json_use_legacy_discarded_value_comparison.md)
       defined non-zero appends `_ldvcmp`.
+    - [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md) defined non-zero appends `_dp`.
 - The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
   underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
   below.
diff --git a/tests/abi/config/CMakeLists.txt b/tests/abi/config/CMakeLists.txt
index 3a8367690..52941dc33 100644
--- a/tests/abi/config/CMakeLists.txt
+++ b/tests/abi/config/CMakeLists.txt
@@ -14,6 +14,20 @@ add_test(
     NAME test-abi_config_noversion
     COMMAND abi_config_noversion ${DOCTEST_TEST_FILTER})
 
+# test default and no version namespace with all ABI tags enabled, so the
+# expected tag order is checked regardless of the JSON_* CMake options
+foreach(test default noversion)
+    add_executable(abi_config_${test}_all_tags ${test}.cpp)
+    target_compile_definitions(abi_config_${test}_all_tags PRIVATE
+        JSON_DIAGNOSTICS=1
+        JSON_DIAGNOSTIC_POSITIONS=1
+        JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1)
+    target_link_libraries(abi_config_${test}_all_tags PRIVATE abi_compat_main)
+    add_test(
+        NAME test-abi_config_${test}_all_tags
+        COMMAND abi_config_${test}_all_tags ${DOCTEST_TEST_FILTER})
+endforeach()
+
 # test custom namespace
 add_executable(abi_config_custom custom.cpp)
 target_link_libraries(abi_config_custom PRIVATE abi_compat_main)
diff --git a/tests/abi/config/default.cpp b/tests/abi/config/default.cpp
index 0edc12e62..f3ee23110 100644
--- a/tests/abi/config/default.cpp
+++ b/tests/abi/config/default.cpp
@@ -24,14 +24,14 @@ TEST_CASE("default namespace")
         expected += "_diag";
 #endif
 
-#if JSON_DIAGNOSTIC_POSITIONS
-        expected += "_dp";
-#endif
-
 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
         expected += "_ldvcmp";
 #endif
 
+#if JSON_DIAGNOSTIC_POSITIONS
+        expected += "_dp";
+#endif
+
         expected += "_v" STRINGIZE(NLOHMANN_JSON_VERSION_MAJOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_MINOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_PATCH) "::basic_json";
diff --git a/tests/abi/config/noversion.cpp b/tests/abi/config/noversion.cpp
index 2ae5cf5ac..cbdcb149b 100644
--- a/tests/abi/config/noversion.cpp
+++ b/tests/abi/config/noversion.cpp
@@ -25,14 +25,14 @@ TEST_CASE("default namespace without version component")
         expected += "_diag";
 #endif
 
-#if JSON_DIAGNOSTIC_POSITIONS
-        expected += "_dp";
-#endif
-
 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
         expected += "_ldvcmp";
 #endif
 
+#if JSON_DIAGNOSTIC_POSITIONS
+        expected += "_dp";
+#endif
+
         expected += "::basic_json";
 
         // fallback for Clang