Rails 5.1 rake dev:cache interfering with restarting the puma server

[skunkworker]

With Rails 5.1 adding the rake dev:cache command. Code here
the default strategy of watch('tmp/caching-dev.txt') would fail when running rake dev:cache in another terminal window. As it would complain that the pid already exists. I looked into the implementation in the rails master branch and it turns out that by default it is removing the pid file on tmp/pids/server.pid. Adding this config to the guardfile fixed the issue. Is this a rails issue not respecting other pid files?

[skunkworker]

Current config

guard 'rails', port: 3000, host: '0.0.0.0', force_run: true, pid_file: 'tmp/pids/server.pid' do
  watch('Gemfile.lock')
  watch(%r{^(config|lib)/.*})

  watch('tmp/caching-dev.txt') # for Rails 5.1 testing of caching.
end

[ranmocy]

After some tests, I believe this is a Rails bug. Created the Rails issue here.
The issue exists regardless guard-rails. Even simple rails s -P tmp/pids/dev.pid would reproduce the issue.

BTW, watch('tmp/caching-dev.txt') is not necessary. Rails would trigger the restarting by itself. My config:

guard 'rails', pid_file: 'tmp/pids/server.pid' do
  watch('Gemfile.lock')
  watch(%r{^(config|lib)/.*})
end

[skunkworker]

@ranmocy that's one of the conclusions I came to as well, it seems as though they hardcode the PID file in multiple places and don't respect other locations.

[skunkworker]

And thanks for the input about not having to watch the caching-dev.txt file, just the pid going is enough it seems to trigger the restarting. 👍