googletest does not respect CMake's CMP0091 policy.

[Atari2]

Describe the bug

googletest relies on CMake setting the /MD compiler flag as a default https://github.com/google/googletest/blob/9c332145b71c36a5bad9688312c79184f98601ff/googletest/cmake/internal_utils.cmake#L40 However, if CMP0091 is set to NEW this doesn't happen anymore. Because of this, googletest will always use the dynamic version of the CRT and as such, errors like this:

gtest.lib(gtest-all.cc.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MDd_DynamicDebug' doesn't match value 'MTd_StaticDebug' in main.cpp.obj

when linking against something that uses the static version of the CRT. This behavior happens regardless of whether gtest_force_shared_crt is set to OFF or ON (or set at all), because the string(REPLACE ...) function used doesn't replace anything because the expected /MD flag is not present in any of the flags inspected by the fix_default_compiler_settings_ macro.

My personal temporary fix was doing

set_property(TARGET gtest PROPERTY MSVC_RUNTIME_LIBRARY "<proper msvc runtime library here>")
set_property(TARGET gtest_main PROPERTY MSVC_RUNTIME_LIBRARY "<proper msvc runtime library here>")

after the FetchContent_MakeAvailable(googletest) call. This makes it so the targets now respect the setting given by CMP0091. This also completely overrides the need to set gtest_force_shared_crt.

Steps to reproduce the bug

Clone https://github.com/Atari2/SpriteToolSuperDelux Switch to gtest-fail-link branch Run

mkdir build
cd build
cmake -S .. -DMSVC_STATIC_STL=ON
cmake --build . --config Debug --target PixiUnitTest

and observe the linking bug between harness.cpp.obj and gtest-all.obj.

Does the bug persist in the most recent commit?

Yes

What operating system and version are you using?

Windows 10, 22H2 build 19045.2251

What compiler and version are you using?

Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31933 for x64

What build system are you using? cmake version 3.24.2