First load in dev environment is extremely slow after upgrading from Rails 5.1 -> 5.2.1

[allaud]

Steps to reproduce

Just upgraded Rails and its dependencies from 5.1.0 to 5.2.1. I see the first page load is extremely slow (takes more than 10 minutes). And after that everything works fine and fast enough.

My Gemfile: https://gist.github.com/allaud/c60788ba96323be4eb50cc86aad22df6
Gemfile.lock: https://gist.github.com/allaud/5deb0d677a33dfbad66d261ad13c751d
Console when it hangs: https://gist.github.com/allaud/f785fc7baf8fc712f8e15790ba1b5f79

Expected behavior

Page loads in ~1-2 seconds

Actual behavior

Page loads more then 10 minutes (after the first load all pages load fast enough)

System configuration

Rails version: 5.2.1

Ruby version: ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-darwin17]

[rafaelfranca]

Can you please provide a sample application that reproduces the error?

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
The resources of the Rails team are limited, and so we are asking for your help.
If you can still reproduce this error on the 5-2-stable branch or on master, please reply with all of the information you have about it in order to keep the issue open.
Thank you for all your contributions.