🎩 What? Why?

I received the following error in a recent action run:

#<Thread:0x00007f0b1b1519e0 /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/capybara-3.40.0/lib/capybara/server.rb:76 run> terminated with exception (report_on_exception is true):
/opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:334:in initialize': Address already in use - bind(2) for "127.0.0.1" port 6242 (Errno::EADDRINUSE) from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:334:in new'
from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:334:in add_tcp_listener' from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:163:in block in parse'
from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:146:in each' from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/binder.rb:146:in parse'
from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/capybara-3.40.0/lib/capybara/registrations/servers.rb:63:in block (2 levels) in <top (required)>' from <internal:kernel>:90:in tap'
from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/capybara-3.40.0/lib/capybara/registrations/servers.rb:62:in block in <top (required)>' from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/capybara-3.40.0/lib/capybara/config.rb:64:in block in server='
from /opt/hostedtoolcache/Ruby/3.2.2/x64/lib/ruby/gems/3.2.0/gems/capybara-3.40.0/lib/capybara/server.rb:77:in `block in boot'

Whole logs available at:
https://github.com/decidim/decidim/actions/runs/10042209706/job/27752308455?pr=12576

I think this is related to the fact that the Redis port is not mapped to the host machine because Redis should take care of keeping a list of reserved ports (although conflicts are still possible if the port resolution happens exactly at the same time.

Also I marked the Redis port to be skipped in order to keep that reserved for Redis.

📌 Related Issues

• Related to Use redis in CI to prevent conflicting/reserved capybara ports #12705

Testing

I don't think there is an easy way to test this other than trying to re-introduce a port conflict which requires running the workflows several times.