Bootsnap causes server to hang in Ruby 3.2.1

[alexdelgado]

I made sure the issue is in bootsnap

Yes, deleting bootsnap cache folder consistently resolves the isssue.

Steps to reproduce

1. Install Ruby 3.2.1 (or 3.2.2)
2. Run rails s
3. Server runs normally
4. Restart server
5. Browser hangs
6. Stop browser
7. Remove tmp/cache/bootsnap
8. Start server
9. Browser loads properly

Expected behavior

Browser shouldn't hang on restart

Actual behavior

Browser hangs on restart

System configuration

Bootsnap version: 1.16.0, 1.15.0

Ruby version: 3.2.1, 3.2.2

Rails version: 7.0.4.3

[casperisfine]

This happen on every single restart?

Steps to reproduce

Sorry, but if it was this simple thousands of people would have ran into it.

Any idea what the Ruby process hang onto?

Can you try adding something like this in config/boot.rb:

main_thread = Thread.current
Thread.new do
  loop
    puts '-' * 40
    puts main_thread.backtrace
    sleep 1
  end
end

If it's stuck with the GVL released that should print the backtrace, if it's stuck in C land with the GVL held, it probably won't output anything once stuck. We'd at least know that.

Also are you using NFS or some kind of shared volume (e.g. Docker Desktop or something)? bootsnap does some raw C IOs for performance without releasing the GVL, so it's possible it's getting stuck on file system operations.

[kyle-annen]

Experiencing similar issues

Logs using the snippet above in `config/boot.rb`

``` [LDClient] Stream initialized [44525] - Worker 0 (PID: 44656) booted in 0.23s, phase: 0 ---------------------------------------- /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `wait_readable' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/launcher.rb:193:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/rack/handler/puma.rb:72:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/server.rb:327:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:38:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:143:in `block in perform' :90:in `tap' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:134:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command/base.rb:87:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command.rb:48:in `invoke' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands.rb:18:in `

' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' bin/rails:4:in `

' ---------------------------------------- /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `wait_readable' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/launcher.rb:193:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/rack/handler/puma.rb:72:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/server.rb:327:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:38:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:143:in `block in perform' :90:in `tap' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:134:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command/base.rb:87:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command.rb:48:in `invoke' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands.rb:18:in `

' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' bin/rails:4:in `

' ---------------------------------------- /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `wait_readable' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/launcher.rb:193:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/rack/handler/puma.rb:72:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/server.rb:327:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:38:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:143:in `block in perform' :90:in `tap' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:134:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command/base.rb:87:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command.rb:48:in `invoke' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands.rb:18:in `

' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' bin/rails:4:in `

' ---------------------------------------- /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `wait_readable' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/launcher.rb:193:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/rack/handler/puma.rb:72:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/server.rb:327:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:38:in `start' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:143:in `block in perform' :90:in `tap' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:134:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command/base.rb:87:in `perform' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command.rb:48:in `invoke' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands.rb:18:in `

' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' /Users/kyle/.asdf/installs/ruby/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require' bin/rails:4:in `

' ```

[themoffatt]

Sorry, but if it was this simple thousands of people would have ran into it.

I get the sentiment here, but it's not super helpful. This has been reproduced on multiple machines. I'll add some more information that might help us see if this truly is something specific to bootsnap or not. I'm trying to understand more about the caching that bootsnap is doing to see why things work fine on that first app boot, but fail on the second. It's wrecking my brain trying to find what could be different/wrong on that second boot.

It seems to be specific to Rails 7 and Ruby 3.2.X. Switching back to Ruby 3.1.2 with no other changes, resolves the issue. I haven't tried this with a lower version of Rails.

This looks to be something specific to puma. I've found that bootsnap is working fine when using webrick. rails s -u webrick. Using thin also works fine.

When I boot the app the second time after clearing the bootsnap cache, I start getting this error. Commenting out require 'bootsnap/setup' in boot.rb and restarting the server immediately resolves this.

Puma caught this error: undefined method `execute_if_updated' for nil:NilClass (NoMethodError)
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionview-7.0.4.3/lib/action_view/cache_expiry.rb:51:in `block in execute_if_updated'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionview-7.0.4.3/lib/action_view/cache_expiry.rb:42:in `synchronize'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionview-7.0.4.3/lib/action_view/cache_expiry.rb:42:in `execute_if_updated'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionview-7.0.4.3/lib/action_view/cache_expiry.rb:15:in `block in run'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/dependencies/interlock.rb:41:in `permit_concurrent_loads'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionview-7.0.4.3/lib/action_view/cache_expiry.rb:14:in `run'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/execution_wrapper.rb:29:in `before'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:423:in `block in make_lambda'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:199:in `block (2 levels) in halting'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:687:in `block (2 levels) in default_terminator'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:686:in `catch'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:686:in `block in default_terminator'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:200:in `block in halting'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:595:in `block in invoke_before'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:595:in `each'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:595:in `invoke_before'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/callbacks.rb:106:in `run_callbacks'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/execution_wrapper.rb:129:in `run'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/execution_wrapper.rb:125:in `run!'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/execution_wrapper.rb:78:in `block in run!'
<internal:kernel>:90:in `tap'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/activesupport-7.0.4.3/lib/active_support/execution_wrapper.rb:75:in `run!'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionpack-7.0.4.3/lib/action_dispatch/middleware/executor.rb:12:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/rack-livereload-0.3.17/lib/rack/livereload.rb:23:in `_call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/rack-livereload-0.3.17/lib/rack/livereload.rb:14:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionpack-7.0.4.3/lib/action_dispatch/middleware/static.rb:23:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/sendfile.rb:110:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/actionpack-7.0.4.3/lib/action_dispatch/middleware/host_authorization.rb:137:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/engine.rb:530:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/configuration.rb:252:in `call'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/request.rb:77:in `block in handle_request'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/thread_pool.rb:340:in `with_force_shutdown'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/request.rb:76:in `handle_request'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/server.rb:443:in `process_client'
/Users/myusername/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/thread_pool.rb:147:in `block in spawn_thread'

I'm also going to try the suggestions you made for checking more things. Thanks for sharing that too. I'll report back on that shortly.

[themoffatt]

I added the snippet you suggested (thanks for that!) and here's what I see being printed every 1 second

/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `wait_readable'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/cluster.rb:437:in `run'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/puma/launcher.rb:193:in `run'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/puma-5.6.5/lib/rack/handler/puma.rb:72:in `run'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/rack-2.2.6.4/lib/rack/server.rb:327:in `start'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:38:in `start'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:143:in `block in perform'
<internal:kernel>:90:in `tap'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands/server/server_command.rb:134:in `perform'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command/base.rb:87:in `perform'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/command.rb:48:in `invoke'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/railties-7.0.4.3/lib/rails/commands.rb:18:in `<main>'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require'
/Users/my_user/.rbenv/versions/3.2.1/lib/ruby/gems/3.2.0/gems/bootsnap-1.15.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:32:in `require'
bin/rails:4:in `<main>'

[casperisfine]

Thanks for the answers, I'll have another round of questions.

Experiencing similar issues

@kyle-annen is this a totally different app, or are you @themoffatt coworker? I'm a bit surprised to see two persons hitting such huge bug I never heard of the same week.

I get the sentiment here, but it's not super helpful.

Apologies, I didn't mean to be snarky or anything, I just meant that these steps weren't actionable.

This has been reproduced on multiple machines.

But same application, right?

It seems to be specific to Rails 7 and Ruby 3.2.X. Switching back to Ruby 3.1.2 with no other changes, resolves the issue.

That's a very useful information, thank you. If it's not too much trouble, trying 3.1.4 and 3.2.0 could be interesting. If some 3.1.x patch version also fail, or some 3.2.x patch versions works, It would mean this is caused by a change in Ruby that was backported, and that would make it easier to pinpoint it.

This looks to be something specific to puma. I've found that bootsnap is working fine when using webrick. rails s -u webrick. Using thin also works fine.

Also very interesting, that hints at a Mutex or Monitor issue. Initially I thought it could be another fallout from https://bugs.ruby-lang.org/issues/17827, but if that was the case, I think 3.1.2 would also be broken.

undefined method `execute_if_updated' for nil:NilClass (NoMethodError)

Hum, so @watcher would be nil here: https://github.com/rails/rails/blob/c15ee6e7b5065db3c46afa1f025b8e45f443604e/actionview/lib/action_view/cache_expiry.rb#L51

That is very weird, I don't get how that could possibly happen.

Another question: Are you using spring ? If so does spring stop also solve the issue?

here's what I see being printed every 1 second

Thank you, however I realize my snippet was a bit incorrect, as since you are using Puma, the main thread isn't the one we care for. Here we simply see puma waiting for another request.

Can you try this instead:

Thread.new do
  loop
    puts '-' * 40
    Thread.list.each do |thr|
    puts main_thread.backtrace
    sleep 1
  end
end

This will print the backtraces of all threads, so it should include the Rails request one, and that should tell us where it's stuck.

[themoffatt]

Thanks @casperisfine. No worries, sorry we didn't post more info in the original. I've actually spun up a fresh rails app and don't see this issue with bootsnap on 3.2.1 either. So it has to be something specific with our app or the Gems we're using. My suspicion is GoodJob or LaunchDarkly. I'm going to try your suggestion above and report back.

If nothing else, if we can find exactly what's causing this issue maybe it'll help someone in the future who has a similar setup to us. :)