[Tarantool-patches] [PATCH luajit 2/6] test: refactor CMake macro LibRealPath

[Sergey Bronnikov]

From: Sergey Bronnikov <sergeyb at tarantool.org>

The patch refactors the CMake macro LibRealPath:

- Replace CMAKE_CXX_COMPILER with CMAKE_C_COMPILER because
  LuaJIT doesn't require the CXX compiler, and thus it can be
  unavailable on a build system.
- Add a check for a code returned by a command with the compiler.
- Add a check for a value returned by the compiler. A value equal
  to a passed one means that the library was not found in
  the system.
- Unset local variables to avoid namespace pollution.

Needed for tarantool/tarantool#9656
---
 test/LuaJIT-tests/CMakeLists.txt | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/test/LuaJIT-tests/CMakeLists.txt b/test/LuaJIT-tests/CMakeLists.txt
index a0fb5440..badec91d 100644
--- a/test/LuaJIT-tests/CMakeLists.txt
+++ b/test/LuaJIT-tests/CMakeLists.txt
@@ -33,18 +33,41 @@ if(LUAJIT_USE_ASAN)
   # https://github.com/google/sanitizers/issues/934.
   macro(LibRealPath output lib)
     execute_process(
-      COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=${lib}
+      # CMAKE_C_COMPILER is used because it has the same behaviour
+      # as CMAKE_CXX_COMPILER, but CMAKE_CXX_COMPILER is not
+      # required for building LuaJIT and can be missed in GH
+      # Actions.
+      COMMAND ${CMAKE_C_COMPILER} -print-file-name=${lib}
       OUTPUT_VARIABLE LIB_LINK
       OUTPUT_STRIP_TRAILING_WHITESPACE
+      RESULT_VARIABLE RES
     )
+
+    if(NOT RES EQUAL 0)
+      message(FATAL_ERROR
+        "Executing '${CMAKE_C_COMPILER} -print-file-name=${lib}' has failed"
+      )
+    endif()
+
+    # GCC and Clang return a passed filename when a library is
+    # not found.
+    if(LIB_LINK STREQUAL ${lib})
+      message(FATAL_ERROR "Library '${lib}' is not found")
+    endif()
+
     # Fortunately, we are not interested in macOS here, so we can
-    # use realpath.
+    # use realpath. Beware, `realpath` always returns an exit code
+    # equal to 0, so we cannot check if it fails.
     execute_process(
       COMMAND realpath ${LIB_LINK}
       OUTPUT_VARIABLE ${output}
       OUTPUT_STRIP_TRAILING_WHITESPACE
     )
+
+    unset(LIB_LINK)
+    unset(RES)
   endmacro()
+
   LibRealPath(LIB_STDCPP libstdc++.so)
   # XXX: GCC requires both. Clang requires only libstdc++.
   if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
-- 
2.34.1