I went down this particular rabbit hole of trying to terminate processes reliably a few years ago. The context was termination of tasks and tests by Bazel. You

I went down this particular rabbit hole of trying to terminate processes reliably a few years ago. The context was termination of tasks and tests by Bazel. You can find the text in https://jmmv.dev/2019/11/wait-for-process-group.html https://jmmv.dev/2019/11/wait-for-process-group.html and the two extra linked posts in the last paragraph, one providing a solution for Linux and the other for macOS. It isn’t pretty nor easy, but it’s doable to various degrees of correctness.