can't add a new key into hash during iteration

[gingerlime]

Describe the bug
We saw this error (albeit only once) after upgrading to the latest coverband

To Reproduce
Not sure unfortunately...

Here's part of the stack trace

1
File "/usr/lib/ruby/3.0.0/set.rb" line 355 in add
2
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/coverband-5.2.0/lib/coverband/collectors/view_tracker.rb" line 53 in track_views
3
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/coverband-5.2.0/lib/coverband/utils/railtie.rb" line 41 in block (2 levels) in <class:Railtie>
4
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/fanout.rb" line 186 in finish
5
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/fanout.rb" line 63 in block in finish
6
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/fanout.rb" line 63 in each
7
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/fanout.rb" line 63 in finish
8
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/instrumenter.rb" line 45 in finish_with_state
9
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications/instrumenter.rb" line 30 in instrument
10
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/activesupport-6.1.4.4/lib/active_support/notifications.rb" line 203 in instrument
11
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/actionview-6.1.4.4/lib/action_view/renderer/partial_renderer.rb" line 280 in render_partial_template
12
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/actionview-6.1.4.4/lib/action_view/renderer/partial_renderer.rb" line 271 in render
13
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/actionview-6.1.4.4/lib/action_view/renderer/renderer.rb" line 81 in render_partial_to_object
14
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/actionview-6.1.4.4/lib/action_view/renderer/renderer.rb" line 53 in render_partial
15
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/actionview-6.1.4.4/lib/action_view/helpers/rendering_helper.rb" line 45 in render
16
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/haml-5.2.2/lib/haml/helpers/action_view_mods.rb" line 13 in block in render
17
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/haml-5.2.2/lib/haml/helpers.rb" line 93 in non_haml
18
File "/var/local/kenhub/kenhub.d/73/vendor/bundle/ruby/3.0.0/gems/haml-5.2.2/lib/haml/helpers/action_view_mods.rb" line 13 in render
19
File "/var/local/kenhub/kenhub.d/73/app/views/layouts/_base_header.haml", line 3 in block in _app_views_layouts__base_header_haml__4267542119396688185_99240

Expected behavior
No error? :)

Screenshots
see above

Desktop (please complete the following information):

• OS: [e.g. iOS] Windows 10
• Browser [e.g. chrome, safari] Chrome
• Version [e.g. 22] 96

Additional context
It seemed to have happened shortly after deploying the latest version of coverband, but only to one user, and only once...

[danmayer]

hmm thanks @gingerlime I haven't been able to reproduce yet... I am upgrading a bunch of apps in the next week so perhaps I will see it as the deployment expands. If you see it again let me know... Might need to dig a bit more into that bit in the view tracker

[gingerlime]

Thanks @danmayer. It seemed to have happened in both our staging and live environment, but only once in each environment after we upgraded... So I'm not entirely sure how to reproduce it either... I can try to play with it a bit and maybe clear the data, but it might be more tricky and time-consuming if I have to downgrade/upgrade obviously... Hope you can spot something as well.

[danmayer]

OK, interesting the once per environment gives me at least a clue about it being a one time upgrade issue.

[gingerlime]

yep seems very likely. maybe not worth worrying about then? but just thought better safe than sorry so I reported it :)

[gingerlime]

Hi @danmayer. We just got this error again on deploy. I'm not entirely sure what changed in our code to have triggered it, but it now looks like it's not a completely one-off thing...

[danmayer]

OK, I will take a closer look and see if I can reproduce it tonight. Can you share your Rails, Ruby, and Redis version?

[gingerlime]

Thank you! We're using Rails 6.1, Ruby 3.0.2 and Redis 5.x (redis-rb is 4.5.1)

[danmayer]

OK, pushed up what I think should be a fix. It still hasn't reproduced on any of our apps, but I am pretty sure I see where the thread race condition in our view tracker could occur.

Try out this RC release and let me know if it solves the issue 5.2.1.rc.1

[gingerlime]

can’t repro reliably either but will give it a try :) thank you!

[gingerlime]

We still see some errors on deploy on production (not every deploy, but some), and with the rc on staging, we don't see those errors... So it looks like a safe bet 👍

[danmayer]

OK great, I released 5.2.1 to rubygems. If you see more let me know