fix: sol2 header to allow for empty lua macro definitions (#7441)

nilsnolde · web-flow · commit ed0e7472956c · 2026-03-31T09:59:36.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -31,6 +31,7 @@
       - FIXED: Work around compilation error due to a false-positive of array-bounds check in sol2 [#7317](https://github.com/Project-OSRM/osrm-backend/pull/7317)
       - FIXED: Fix compilation with gcc >14 in release with LTO. [#7268](https://github.com/Project-OSRM/osrm-backend/issues/7268)
       - ADDED: Conditionally prefix custom CMake targets with `osrm_` when built as subproject, and add ALIAS targets for FetchContent compatibility [#7267](https://github.com/Project-OSRM/osrm-backend/issues/7267)
+      - FIXED: Compilation error in vendored sol2 when LUA_COMPAT_BITLIB or LUA_COMPAT_5_2 are defined as empty macros [#00](https://github.com/Project-OSRM/osrm-backend/issues/00)
     - Misc:
       - CHANGED: Upgrade from clang-format-15 to clang-format-18 [#7249](https://github.com/Project-OSRM/osrm-backend/issues/7249)
       - ADDED: `--output` / `-o` option to osrm-extract for specifying custom output base path [#4930](https://github.com/Project-OSRM/osrm-backend/issues/4930)
diff --git a/third_party/sol2/include/sol/sol.hpp b/third_party/sol2/include/sol/sol.hpp
@@ -3107,7 +3107,7 @@ struct pre_main {
 #else
 	// Lua 5.2 only (deprecated in 5.3 (503)) (Can be turned on with Compat flags)
 	// Lua 5.2, or other versions of Lua with the compat flag, or Lua that is not 5.2 with the specific define (5.4.1 either removed it entirely or broke it)
-	#if (SOL_LUA_VERSION_I_ == 502) || (defined(LUA_COMPAT_BITLIB) && (LUA_COMPAT_BITLIB != 0)) || (SOL_LUA_VERSION_I_ < 504 && (defined(LUA_COMPAT_5_2) && (LUA_COMPAT_5_2 != 0)))
+	#if (SOL_LUA_VERSION_I_ == 502) || (defined(LUA_COMPAT_BITLIB) && (LUA_COMPAT_BITLIB+0 != 0)) || (SOL_LUA_VERSION_I_ < 504 && (defined(LUA_COMPAT_5_2) && (LUA_COMPAT_5_2+0 != 0)))
 		#define SOL_LUA_BIT32_LIB_I_ SOL_ON
 	#else
 		#define SOL_LUA_BIT32_LIB_I_ SOL_DEFAULT_OFF
