Re: concurrent access to multiple local git repos is error prone

[Alexander Mills <alexander.d.mills@gmail.com>]

To add something to the previous message, I have strong evidence that
the problem occurs when *different* repos are accessed concurrency,
not the same repo, as bizarre as that may be.

-alex

On Mon, Aug 6, 2018 at 12:36 AM, Alexander Mills
<alexander.d.mills@gmail.com> wrote:
> Hi Johnathan,
>
> Yeah this concurrency problem is real. Not only does it happen with
> `git status` the same thing happens with `git rev-parse
> --show-toplevel`.
> What happens is that I get no stdout when repos are accessed
> concurrently (and no stderr). If I limit concurrency to 1, the problem
> goes away. When I up the concurrency, the problem is sporadic, which
> is the exact signal for a concurrency/race-condition related issue.
> The signs are damn clear. I have seen this problem on MacOS I think a
> year back on a different project, but I never reported it b/c I hadn't
> really verified it.
>
> Like I said I am on Ubuntu. I have 3 git repos that are incorporated
> into the tool that's generating the problem. For one repo I got this:
>
> $ git fsck
>
> Checking object directories: 100% (256/256), done.
> dangling tree 4b825dc642cb6eb9a060e54bf8d69288fbee4904
>
> For `$ git version --build-options` I have:
>
> git version 2.17.1
> cpu: x86_64
> no commit associated with this build
> sizeof-long: 8
>
>
> -alex
>
>
>
> On Sun, Aug 5, 2018 at 1:11 AM, Jonathan Nieder <jrnieder@gmail.com> wrote:
>> Alexander Mills wrote:
>>
>>> Yeah in this case what appeared to be happening is that if `git status` was
>>> called concurrently, frequently I wouldnt get any stdout..
>>
>> Thanks for reporting.  A few questions:
>>
>> What platform are you on?  What version of Git are you running?  What
>> is the output of "git version --build-options"?
>>
>> What is the exit status from these "git status" invocations that
>> didn't write output?  What options are you passing to "git status"?
>> Are there any other interesting symptoms?
>>
>> Is this part of a larger tool or script?  Are there other operations
>> going on (e.g. something sending signals to these git processes)?
>>
>> Does the repository pass "git fsck"?  Any other symptoms or hints that
>> could help in tracking this down?
>>
>> Can you paste a transcript of the commands or script you ran and what
>> output it produced?  Is this something I should be able to reproduce?
>>
>> Thanks and hope that helps,
>> Jonathan
>
>
>
> --
> Alexander D. Mills
> ¡¡¡ New cell phone number: (415)730-1805 !!!
> alexander.d.mills@gmail.com
>
> www.linkedin.com/pub/alexander-mills/b/7a5/418/



-- 
Alexander D. Mills
¡¡¡ New cell phone number: (415)730-1805 !!!
alexander.d.mills@gmail.com

www.linkedin.com/pub/alexander-mills/b/7a5/418/