tcp_answer metric not accurate

[dal13002]

• [X] This is not a support question, I have read about opensource and will send support questions to the IRC channel, GitHub Discussions or the mailing list.
• [X] I have read and understood the 'out in the open' support policy
• [X] I have read and understood the PowerDNS AI policy

• Program: Authoritative
• Issue type: Bug report

Short description

When using type ALIAS, it seems like tcp-answers metric is not increasing in count. Even though the tcp query is successfully returned the metric count is not increased. Note: this does seem to work fine using the udp-answer metric.

Environment

• Operating system: Linux (container)
• Software version: 5.0.0
• Software source: Official Docker image

Steps to reproduce

1. Create Alias record that will expand alias
2. Resolve the alias record using tcp (ie dig +tcp <record> @<server-ip> +short)
3. Look at /metrics endpoint of the api. The tcp_answers count metric will not increase even though an answer was given

Expected behaviour

tcp_answers count to increase when answer is given on Alias record

Actual behaviour

tcp_answers count is not increased on metrics endpoint

Other information

N/A