this is where the special “exit from parent” is implemented: otp/lib/stdlib/src/gen_server.erl at master · erlang/otp · GitHub

This is excellent. Thankyou so much for writing this!

Just one point: I think there is a further difference in behaviour if the process doing the killing is the direct parent of the child? I’m actually not sure I understand the specifics, but there was a post on elixirforum a month or so back about this and the insight was that the child can’t catch it’s own exit if the thing sending the message is the direct parent? I think if this is correct then it would be quite nice to get this documented in your rather comprehensive write-up on this stuff!

I confess I still have a lot of doubts over how to correctly use OTP and especially how best to link some children and guarantee cleanup. I quite like the “parent” library for some of these things (“director” seems nice as well). I think it’s clear from your document that there are a few preferred ways to kill processes if you want to allow them to call their terminate() function. It does leave me with some doubts on how to handle this as a library author as well…

Looking forward to see if you do a followup on this on? Perhaps with regards to how to build robust links, cleanup on failure, monitor callers to ensure we terminate when our invoker terminates, etc?

I think so too. Links are bidirectional, see Process — Elixir v1.12.3

But you can implement some stuff that makes one process behave like a parent.
See Parent - custom parenting of processes

Thank you for this great and deadly blog-series!