Explore preventing add-ons from exiting the process

[vinistock]

Currently, if an add-on executes exit, the Ruby LSP process will die and cause the editor connection to crash.

I've been wondering if we can prevent that from happening. My idea would be to capture the original exit method in a constant (so that we can ourselves use it when shutting down) and then override it to no-op.

Something like this:

ORIGINAL_EXIT = Kernel.method(:exit)

module Kernel
  def exit
    # do nothing
  end
end

# when shutting down
ORIGINAL_EXIT.call

[ryan-robeson]

Rather than redefining exit globally, would it be sufficient to rescue from SystemExit at the calls to add-on methods? Or perhaps implement an Addon::notify method? Something like:

# Example usage
# Context: Addon.addons.each do |addon|
# This:
# addon.create_code_lens_listener(@response_builder, uri, dispatcher)
# Becomes:
# Addon.notify(addon, :create_code_lens_listener, @response_builder, uri, dispatcher)
def notify(addon, event, *args)
  addon.send(event, *args) if addon.respond_to?(event)
rescue SystemExit
  puts "Add-on #{addon.name} attempted to exit the process while calling #{event} with args (#{args}). Ignoring..."
end

[vinistock]

It might be, but we need to rescue that error in every API point that add-ons have access to. I never actually tried rescuing SystemExit before, so I'd need to confirm it handles all of the different ways to exit (exit, abort...).

[ryan-robeson]

Cool. I submitted a PR for the Addon::notify solution so you can see what you think. It likely will need changes. Wasn't sure if it should catch StandardError too or the proper way to log messages.

Another alternative would be to wrap Addon instances in a class when they're instantiated in load_addons that would wrap the methods with error handling and delegate to that instance. I'm not sure if that would be an improvement though.