Removing hooks?

[cmtonkinson]

I don't see any (documented or not) method to remove a hook. Is this possible, even if not fully supported? How would I do this?

If I wanted to remove all Hooks by name, it looks like I might be able to run self._hooks[:hook_name] = nil but it's not clear that

1. This is "safe"
2. This wouldn't result in memory leak for a long-running process.

I know this is more a pub/sub workflow than hooking, strictly speaking, but it would be awfully helpful (to my current challenge). Lacking a proper solution or viable hack, I'll have to rip out this gem and replace it with a pub/sub alternative, which I don't look forward to.

[apotonick]

Hi Chris,

the _hooks object uses inheritable_attr which is "safe" to manipulate in subclasses. We do it all the time in many gems. What makes you think it could lead to memory leaks?

https://github.com/apotonick/hooks/blob/master/lib/hooks.rb#L25

[cmtonkinson]

Thanks for pointing to the use of inheritable_attr (I'd missed that).

With respect to safety - I shouldn't have said "memory leak." Poor question asking on my part, I apologize. I should have instead asked whether you create any other references to the callable objects stored in _hooks, such that if I remove a hook and relinquish the last variable in my code which references to said callable, the runtime will be able to GC it.

[apotonick]

It's a valid, justified question! I had many memory leaks!..... with ActiveRecord haha! 😬

If you change the _hooks "content" in B, its superclass A will still reference all the objects, so GC won't pick up anything here. Are you planning to change hooks dynamically at runtime? What will happen to the superclasses?

[cmtonkinson]

In my use case, I'm wanting to dynamically add-and-remove instance hooks. Like I said, I may be pushing the design boundaries of the gem to the breaking point.

[apotonick]

Uhm, no, no. I haven't worked with this gem for a long time, but I can't see why this wouldn't work.

Have you considered using Trailblazer's Operations for your use case?