Hanging when used in Rails app

[cguess]

First: thanks for the great tool, I was going to implement this myself but instead I'll definitely help out if possible to improve via a PR or two.

Second: When attempting to calculate within a Rails console the system just hangs indefinitely. I'm using Rails 6.1.4 and Ruby 3.0.1. Running just a basic Ruby console (i.e. irb) in the same version works perfectly, so it's something within the Rails stack that's causing this.

Any chance there's something off the top of anyone's head that could be causing this?

[Nakilon]

@cguess thank you for appreciating the project!

Unfortunately I have zero clue in Rails but the gem was tested on 3.0.0 at least.
Your issue pretty much reminds me this one libvips/ruby-vips#310 -- IIRC they with @jcupitt decided it was something about how Rails scales.
Maybe you can tweak something in your Rails configs to see it it's the same issue. If not, let me know.

[Nakilon]

P.S.: I don't know the Rails console but as I understood it hangs after you issue a command so you are probably able to press ^C to get a backtrace to see what was the last call in stack where it hanged.

[cguess]

Thanks for the pointers! This is a super basic, brand new Rails app, so it's definitely all odd. I'm going to break out gdb and dig into some internals and my old C debugging skills to try and figure out what's going on and I'll report back.

[jcupitt]

You could try disabling spring. If that's initing libvips and then forking, it could cause the behaviour you are seeing (I think).

Try setting the env var DISABLE_SPRING=1 and running your app again.

[cguess]

@jcupitt that's the ticket! Now on how to figure out a work around that