FindPackage in CMake may mix Lua versions

[Buristan]

I have the following Lua versions installed on my machine:

tree /usr/include/lua*
/usr/include/lua5.1
├── lauxlib.h
├── luaconf.h
├── lua.h
├── lua.hpp
└── lualib.h
/usr/include/lua5.4
├── lauxlib.h
├── luaconf.h
├── lua.h
├── lua.hpp
└── lualib.h
/usr/include/luajit-2.1
├── lauxlib.h
├── luaconf.h
├── lua.h
├── lua.hpp
├── luajit.h
└── lualib.h

ls /usr/lib64/ | grep lua
liblua5.1.so
liblua5.1.so.0
liblua5.1.so.0.0.0
liblua5.4.so
liblua5.4.so.0
liblua5.4.so.0.0.0
libluajit-5.1.so
libluajit-5.1.so.2
libluajit-5.1.so.2.1.1716656478

The mixed part is the custom mutator library, which uses lua_objlen() which is renamed to the lua_rawlen() since Lua 5.2.

As I noticed, when I build luzer like the following:

cmake -S . -B build -DENABLE_TESTING=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++

It finds the Lua header for the 5.1 version but links with the version 5.4.

As a result, the custom mutator library can't be preloaded:

LD_PRELOAD="/home/burii/reviews/ligurio-luzer/ligurio-luzer/build/luzer/libcustom_mutator.so.1" ls
ls: symbol lookup error: /home/burii/reviews/ligurio-luzer/ligurio-luzer/build/luzer/libcustom_mutator.so.1: undefined symbol: lua_objlen

It results in the following test failures when run by Lua 5.4 binary:

$ ctest -V --test-dir build -R luzer_custom_mutator_example
...
7: /usr/bin/lua5.4: ...burii/reviews/ligurio-luzer/ligurio-luzer/luzer/init.lua:48: function LLVMFuzzerCustomMutator is not available
7: stack traceback:
7:      [C]: in function 'luzer_impl.Fuzz'
7:      ...burii/reviews/ligurio-luzer/ligurio-luzer/luzer/init.lua:48: in function 'luzer.Fuzz'
7:      ...-luzer/ligurio-luzer/examples/example_custom_mutator.lua:29: in main chunk
7:      [C]: in ?
1/1 Test #7: luzer_custom_mutator_example .....***Failed  Required regular expression not found. Regex=[example_custom_mutator.lua:19: assert has triggered