CMake GENERATED bug

A minimal example to showcase a potential bug in CMake.

Usage

After cloning this repo to $repo-root, do the following:

cd $repo-root
mkdir build
cd build

# To showcase the expected behaviour
cmake -B . -S .. --log-context --log-level DEBUG -DTRIGGER_WRONG_SEARCH:BOOL=OFF

# To showcase the potential bug
cmake -B . -S .. --log-context --log-level DEBUG -DTRIGGER_WRONG_SEARCH:BOOL=ON

Depending on TRIGGER_WRONG_SEARCH, control flow differs in cmake/AbsPath.cmake::is_generated. With TRIGGER_WRONG_SEARCH=OFF, a workaround is taken which avoids the potential bug. With TRIGGER_WRONG_SEARCH=ON, get_source_file_property is called. The latter tricks CMake into searching for non-generated files in the binary directory at generation time.