How do I introduce find_dependency calls into my generated foo-config.cmake file?

问题

I have a CMake project named foo. In its CMakeLists.txt, and among other commands, I have:

install(
        EXPORT foo_export
        DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/foo"
        NAMESPACE "foo::"
        FILE foo-config.cmake
)

(and also a write_basic_package_version_file() call later on.)

Now, I want foo-config.cmake to also check for a dependency bar of foo, with find_dependency(). How do I do that, other than by replacing the .cmake file generation with something manual?

Notes:

• I'm interested both in the case of bar being a requried dependency and the case of it being optional.
• I would rather not write a foo-config.in unless it's the only option.

来源：https://stackoverflow.com/questions/61815038/how-do-i-introduce-find-dependency-calls-into-my-generated-foo-config-cmake-file