No implicit conversion of nil into String <TypeError>

[jsh562]

Hello,

I am getting this error when running a test from cmd line
thin start -e production -p x

Currently using ruby 2.5.0 on windows

[LindseyB]

I'm hitting this also on my heroku instance that was working previous using ruby 2.7.0. Specifically this is a sinatra app.

2020-02-09T02:19:41.061545+00:00 heroku[web.1]: Process exited with status 1

2020-02-09T02:22:53.755337+00:00 heroku[web.1]: State changed from crashed to starting

2020-02-09T02:22:57.656672+00:00 heroku[web.1]: Starting process with command `bundle exec rackup -p 20454`

2020-02-09T02:23:02.390084+00:00 heroku[web.1]: State changed from starting to crashed

2020-02-09T02:23:02.371600+00:00 heroku[web.1]: Process exited with status 1

2020-02-09T02:23:02.266656+00:00 app[web.1]: bundler: failed to load command: rackup (/app/vendor/bundle/ruby/2.5.0/bin/rackup)

2020-02-09T02:23:02.266717+00:00 app[web.1]: TypeError: no implicit conversion of nil into String

2020-02-09T02:23:02.266718+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/rack/adapter/loader.rb:25:in `join'

2020-02-09T02:23:02.266723+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/rack/adapter/loader.rb:25:in `block in guess'

2020-02-09T02:23:02.266723+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/rack/adapter/loader.rb:24:in `each'

2020-02-09T02:23:02.266724+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/rack/adapter/loader.rb:24:in `guess'

2020-02-09T02:23:02.266724+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/thin/controllers/controller.rb:168:in `load_adapter'

2020-02-09T02:23:02.266724+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/thin-1.7.2/lib/thin/controllers/controller.rb:74:in `start'

2020-02-09T02:23:02.266724+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/rack-2.2.0/lib/rack/handler/thin.rb:27:in `run'

2020-02-09T02:23:02.266724+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/rack-2.2.0/lib/rack/server.rb:327:in `start'

2020-02-09T02:23:02.266725+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/rack-2.2.0/lib/rack/server.rb:168:in `start'

2020-02-09T02:23:02.266725+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/gems/rack-2.2.0/bin/rackup:5:in `<top (required)>'

2020-02-09T02:23:02.266725+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/bin/rackup:23:in `load'

2020-02-09T02:23:02.266730+00:00 app[web.1]:   /app/vendor/bundle/ruby/2.5.0/bin/rackup:23:in `<top (required)>'

It looks like the dir is nil when it tries to do a guess from my local prying into the gem. I'm trying to find a solution.

[leesmith]

With rails 6.0.2.1 and thin 1.7.2 , the latest version of rack I can use is 2.1.2 without getting said error.

[LindseyB]

This sounds like this is a rack issue and not a thin issue in that case. I changed my sinatra setup to use puma instead of thin and it fixed my problem, but that's not truly a solution.

Edit:
Looks like rack/rack#1583 was fixed last night so likely the latest rack should fix this problem. There's also an issue open on rack about the future of thin support with rack.

[ioquatix]

Can you confirm if this is fixed?