Build: the plugin tests build and run on Linux

dingosdk_plugin_tests covers the plugin sandbox and every reskate.* API,
but it only built on Windows, so contributors without Windows could not
run it. Now it builds wherever DINGOSDK_BUILD_PLUGIN_TESTS is on. On
Linux the test target adds plugin_discovery.cpp and mod_list.cpp itself,
because the Linux plugins library leaves out finding plugins among the
mods. The other tests in that group stay Windows only.

mod_list.cpp replaced mods.json and the exclusion list with MoveFileExW.
That code is unchanged under _WIN32. Elsewhere it uses
std::filesystem::rename, which replaces the file in one step on POSIX,
and the error message comes from the error_code.

Ran on Linux (Debian trixie, linux-x64 preset with the plugin and
multiplayer tests on): dingosdk_plugin_tests, dingosdk_server and
dingosdk_server_plugin_tests build, and ctest passes plugins ("plugin
tests passed (15 skipped)", the gitignored contrib/plugins) and
server_plugins. The Windows build was not run.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hs7xxJDf6SDcQUaXnzmtL5

CMakeLists.txt

@@ -442,16 +442,23 @@ if(DINGOSDK_BUILD_CAPTURE_TESTS AND TARGET dingosdk_capture)
     add_test(NAME capture COMMAND dingosdk_capture_tests "${PROJECT_SOURCE_DIR}/External/fonts")
 endif()
 option(DINGOSDK_BUILD_PLUGIN_TESTS "Build plugin host regression tests" OFF)
-if(DINGOSDK_BUILD_PLUGIN_TESTS AND WIN32)
+if(DINGOSDK_BUILD_PLUGIN_TESTS)
     enable_testing()
     # The plugin host apart from the game: manifests, the reskate API, storage, modules, hot reload,
-    # and the sandbox against plugins written to break it.
+    # and the sandbox against plugins written to break it. These build on Linux too, so they can be
+    # run without Windows.
     add_executable(dingosdk_plugin_tests Extension/Plugins/Test/plugin_tests.cpp)
     target_include_directories(dingosdk_plugin_tests PRIVATE "${PROJECT_SOURCE_DIR}")
     target_link_libraries(dingosdk_plugin_tests PRIVATE dingosdk_plugins)
+    if(NOT WIN32)
+        # The Linux plugins library leaves out finding plugins among the mods; the tests need it.
+        target_sources(dingosdk_plugin_tests PRIVATE Extension/Plugins/plugin_discovery.cpp Engine/Vfs/mod_list.cpp)
+    endif()
     # It also runs the test plugins in contrib/plugins.
     target_compile_definitions(dingosdk_plugin_tests PRIVATE "RESKATE_SOURCE_DIR=\"${PROJECT_SOURCE_DIR}\"")
     add_test(NAME plugins COMMAND dingosdk_plugin_tests)
+endif()
+if(DINGOSDK_BUILD_PLUGIN_TESTS AND WIN32)
     # Tricks read from the score HUD's values (Extension/Skater/trick_watch.h), what plugins hear.
     add_executable(dingosdk_trick_watch_tests Extension/Skater/Test/trick_watch_tests.cpp Extension/Skater/trick_watch.cpp)
     target_include_directories(dingosdk_trick_watch_tests PRIVATE "${PROJECT_SOURCE_DIR}")

Engine/Vfs/mod_list.cpp

@@ -4,7 +4,9 @@
 #include "Engine/Core/Json/json.h"
 #include "Engine/Core/Platform/path_text.h"
 
+#ifdef _WIN32
 #include <Windows.h>
+#endif
 
 #include <algorithm>
 #include <cstdint>
@@ -429,7 +431,13 @@ void write_exclusions(const std::filesystem::path& mods_root,
             output.write(text.data(), static_cast<std::streamsize>(text.size()));
             if (!output.flush()) return;
         }
+#ifdef _WIN32
         MoveFileExW(temporary.c_str(), path.c_str(), MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH);
+#else
+        // rename replaces the old file in one step on POSIX, as MoveFileExW does on Windows.
+        std::error_code ignored;
+        fs::rename(temporary, path, ignored);
+#endif
     } catch (...) {}
 }
 
@@ -615,12 +623,23 @@ void save_mod_order(const std::filesystem::path& mods_root, const std::vector<Mo
         if (!output || !output.write(text.data(), static_cast<std::streamsize>(text.size())) || !output.flush())
             throw std::runtime_error("Cannot write " + path_utf8(temporary));
     }
+#ifdef _WIN32
     if (!MoveFileExW(temporary.c_str(), target.c_str(), MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)) {
         std::error_code ignored;
         fs::remove(temporary, ignored);
         throw std::runtime_error("Cannot replace " + path_utf8(target) + " (Windows error " +
             std::to_string(GetLastError()) + ")");
     }
+#else
+    // Elsewhere (the plugin tests on Linux) rename replaces the old file in one step.
+    std::error_code renamed;
+    fs::rename(temporary, target, renamed);
+    if (renamed) {
+        std::error_code ignored;
+        fs::remove(temporary, ignored);
+        throw std::runtime_error("Cannot replace " + path_utf8(target) + " (" + renamed.message() + ")");
+    }
+#endif
 }
 
 } // namespace dingosdk::mods