Error Middleware Rescuable Doesn't Handle Inheritance

[xevix]

Suppose you have an error hierarchy as below:

module APIErrors
  class ParentError < StandardError; end
  class Child < ParentError; end
end

In the API file, suppose you then attempt to rescue from all errors in a standard way:

rescue_from APIErrors::ParentError do |e|
  Rack::Response.new({
    error: "#{e.class} error",
    message: e.message
  }.to_json, e.status)
end

Now suppose a Child error is raised:

raise APIErrors::Child, "Rescue me, please!"

Because the middleware checks only for a list of classes in rescuable?(klass) and the Child class is not included in the list, it will never rescue this.

Is there a way to have all ParentError-derivative classes be rescued?

[dblock]

You can always rescue :all and re-raise an error. But I think we should extend the behavior of rescue_from to allow your scenario. I am not sure what syntax it takes, but I would take a pull request that makes it possible without breaking existing functionality.

[xevix]

Ah, indeed, my fault. My example should have included also other rescue_from for other exceptions such as Grape::Exceptions::ValidationErrors, the idea being to separate different classes of errors. This would be specifically for errors of application-level origin (the API).

Awesome, I'll work on a pull request to enable this.

[dblock]

Closing, fixed in 0.7.0.