Re: Git push race condition?

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: Apr 11, 2014, 07:46 UTC
Message-ID: <vpqob08qpez.fsf@anie.imag.fr>
In-Reply-To: <CAAyEjTO3JTNDxDWpX+k_Z-O9=8-Vu5uyT_1eK-A8nFXWVcyD6w@mail.gmail.com>

Show 19 quoted lines

> This finally happened again. Here's what the reflog looks like:
>
> 2805f68 master@{0}: push
> 96eebc0 master@{1}: push
> 75bd4a6 master@{2}: push
> abc30da master@{3}: push
> eba874f master@{4}: push
> 10981e7 master@{5}: push
> 76b3957 master@{6}: push
> 2e3ea06 master@{7}: push
> 9d4e778 master@{8}: push
> dbd70ae master@{9}: push
> 508ab4f master@{10}: push
> 36a0ce4 master@{11}: push
> ddc258e master@{12}: push
> cf025de master@{13}: push
> dbd70ae master@{14}: push
> 95d33eb master@{15}: push
> 75b8e9a master@{16}: push

You can have a look at the actual reflog (.git/logs/refs/heads/master) which contains a bit more information. It will show you the pairs (source, destination) for each change.

Normally, the destination of a push is the source of the next one, but that would be worth checking.

Show 6 quoted lines

> One interesting thing to note is that dbd70ae shows up at two separate
> points in the reflog though, one being directly before the 9d4e778
> commit that won the race. According to Gitlab's event log that commit
> was just pushed once, right after 95d33eb and before cf025de as it
> shows in master@{14} there. The fact that the same commit shows up
> again in master@{9} is interesting.

My interpretation is that someone/something did a non-fast forward push at master@{9}, which reverted the history back to dbd70ae, and then master@{8} did a fast-forward, non-race condition, absolutely normal push.

Look at the complete reflog line corresponding to master@{9}, it may give you more information.

> Now that it has happened again and I've got this data, I'm going to
> upgrade git but let me know if this provides any insight in the mean
> time.

If I were you, I'd keep a copy of the complete repo (including reflog & all) in case.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/