Broken "compare n commits" link in activity overview when pushing new branch

[nidico]

Gitea Version

1.16.4

Git Version

2.30.2

Operating System

Debian bullseye

How are you running Gitea?

Through the 3rd party debian package repo.

Database

PostgreSQL

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

No response

Description

Pushing to a branch which wasn't previously known to gitea leads to broken compare links like this in the activity overview

https://server/nidi/test-gitea-issues/compare/0000000000000000000000000000000000000000...f6f27fa74aaecedbcf4b4a3625ceafd6fc368ef6

This happens when doing

git push --set-upstream origin branch_name

I wasn't able to reproduce this on try.gitea.io as I stumbled over #19143 instead.

Screenshots

No response