Leonardo Tegon

It turns out that a [bug](https://bugs.ruby-lang.org/issues/13074) was introduced in ruby 2.4 that allowed `#instance_exec` to be executed with the wrong number of arguments. This was fixed on 2.4.1. Ruby 2.3.0:...

I agree, but unfortunately, I'm struggling to find the time to work on this lately, so I'm not sure when I'll be able to do it.

@kgf This one seems too big, I don't think I'll have time to finish it. But thanks anyway.

@stevenharman Looks like it does (although I don't work on that codebase anymore to test it myself).

Sorry guys, I wasn't able to look at this yet, but I'll definitely take a look as soon as I can.

I also had this bug, my workaround was to clear the cache for each spec. ``` ruby JSON::Validator.clear_cache JSON::Validator.validate!(schema_path, response_body, default_optitons.merge(options)) ``` Of course this hurts performance, and i agree...

Eu também pego uma

Hello @benbonnet, thanks for your report. Can you provide us a sample application that reproduces the issue in isolation? You can also use our [bug report template](https://github.com/plataformatec/devise/blob/master/guides/bug_report_templates/integration_test.rb). That would help...

@benbonnet I haven't got the change to look at it yet, sorry. I'll do it when I have some time.

@benbonnet I've made some tests with your app and discovered that `default` has no effect here because we're explicit [sending this value](https://github.com/plataformatec/devise/blob/master/lib/devise/mailers/helpers.rb#L37) inside `headers_for`, so I think your approach is...