use status code explicitly in central config

[YegorZdanovich]

Summary

In http 6.0.0, HTTP::Response::Status was changed from inheriting Delegator to using Comparable + Forwardable. This breaks Range#=== in CentralConfig#fetch_config:

status = HTTP::Response::Status.new(200)
(200..299) === status      # => false (http 6.x)
(200..299) === status.to_i # => true

The case falls through all branches, returns nil, and handle_success(nil) raises NoMethodError: undefined method 'headers' for nil — breaking central config polling silently.

Fix

case resp.status → case resp.status.code in central_config.rb.

Note on v4.8.0

This bug is live in v4.8.0, which has no upper bound on the http dependency (>= 3.0). When Bundler resolves http 6.x, central config breaks silently. A patch release is needed to ship this fix to existing users.

Reproduction

  require "http" # v6.x

  status = HTTP::Response::Status.new(200)

  result = case status
           when 200..299 then :matched
           end

  puts result.inspect  # => nil (expected :matched)

Environment

• elastic-apm 4.8.0
• http 6.0.2
• Ruby 3.3.4

[cla-checker-service]

💚 CLA has been signed

[hegerchr]

@YegorZdanovich thanks for creating this contribution. The proposed changes are breaking for http <6.0. May I ask you to update your branch with the latest changes from main and ensure backwards compatibility with previous http versions?

[janko]

We got bitten by this as well. Due to elastic APM silently failing to pull remote config, this resulted in excessive traffic towards our Observability cluster, and it took a long time to troubleshoot. We needed to monkey-patch http.rb in order to fix this.

[ericmustin]

I rebased this and made a pr #1622

[YegorZdanovich]

@hegerchr sorry for delay, rebased main.