Comment 3 for bug 1878709

>it was copied over from Debian,

Yes, the sourcce was copied/synced from Debian, but to my knowledge all binary packages are rebuilt on Ubuntu?

Anyways, I did some digging [1] and found the build log for amd64 [2]. When searching for any of the troublesome dependencies, I see that they were installed from focal-proposed, for instance:

Get:105 http://ftpmaster.internal/ubuntu focal-proposed/universe amd64 golang-github-prometheus-client-golang-dev all 1.2.1-3 [100 kB]

So it looks like the newer versions were in -proposed, and prometheus built successfully the first time round. It then looks like the newer versions never migrated from -proposed to the -release pocket for unknown reasons and they are currently in groovy-proposed. Prometheus on the other hand, did end up in -release and without the dependencies it now fails to build.

(I am not sure how prometheus migrated to -release before its build dependencies were, I thought that was a requirement in order to avoid issues like this...)

[1] https://bugs.launchpad.net/ubuntu/+source/prometheus/2.15.2+ds-2
[2] https://launchpadlibrarian.net/464644021/buildlog_ubuntu-focal-amd64.prometheus_2.15.2+ds-2_BUILDING.txt.gz
[3] https://launchpad.net/ubuntu/+source/golang-github-prometheus-client-golang