last_event_id not set on Rails custom 500 handling

[chrismdp]

I'm attempting to set up custom error messages so that I can capture information from our users when they hit an issue.

Minimal reproducible example:

• Set config.exceptions_app = self.routes in config/application.rb
• Add route: match "/500", to: "errors#internal_server_error", via: :all
• Set up an error controller with action:

  def internal_server_error
    @sentry_event_id = Sentry.last_event_id
    render status: 500
  end

However, the event isn't being sent until after the action has been run, and therefore the last_event_id method has been called already, returning nil.

Log excerpt:

ActionView::SyntaxErrorInTemplate (Encountered a syntax error while rendering template: check - content_for :body_class app/views/devise/sessions/new.haml:24: syntax error, unexpected end, expecting end-of-input
Processing by ErrorsController#internal_server_error as HTML
  Rendering layout layouts/error.html.haml
  Rendering errors/internal_server_error.html.haml within layouts/error
  Rendered errors/internal_server_error.html.haml within layouts/error (Duration: 0.2ms | Allocations: 16)
  Rendered layouts/_error_tracking.html.haml (Duration: 2.6ms | Allocations: 2238)
  Rendered layout layouts/error.html.haml (Duration: 26.7ms | Allocations: 13990)
Completed 500 Internal Server Error in 8950ms (Views: 28.9ms | ActiveRecord: 0.0ms | Allocations: 31388)

Sending event 5d9cae89107d47299e9ab1f2801add4a to Sentry

Therefore I'm not able to pass the event ID to the Javascript via the view.

This appears to previously work (see #494), so I'm wondering if this is regression in later version of the gem? Or is there a better way of capturing the event id in this case?

• ruby 2.6.6
• rails 6.1.3.1
• sentry-rails 4.3.3
• sentry-ruby 4.3.1

Thanks!

[chrismdp]

@st0012 thanks so much for fixing!