Print error on force push rejection

[aster-void]

Current behavior

Currently, comin silently fails on force push. The journald log only shows "Fetched new commit".

Why it's not good

It took me forever (, which is around a week) to locate the issue and fix it. I didn't realize force push rejection was even a thing until I read the design.md.

Improvement

• Print error on force push rejection.
• In the error, write about how to solve it (rm /var/lib/comin -r)

[nlewo]

I'm really sorry about this 😓 and i could understand you hate me for that!

However, i don't think printing a message is the good way because on complex setup with multiple branches, this message could be printed on each fetch. For instance, when the testing branch is not on top of the main branch, this message would be printed, and this situation can happen quite often.

However, the status command shows this kind of errors: comin status --json | jq .fetcher.
Unfortunately, the CLI is currently not able to show this but i will be working on this.

So, I think to fix this nicely, we need to improve the CLI status command.

[aster-void]

when the testing branch is not on top of the main branch, this message would be printed

Is that an expected situation? if so, what about just printing the error on main branch history mismatch?