Re: Forcing GC to always fail

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Wed, Nov 28 2018, Bryan Turner wrote:

> On Tue, Nov 27, 2018 at 3:47 PM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
>>
>>
>> On Tue, Nov 27 2018, Bryan Turner wrote:
>>
>> >
>> > Is there anything I can set, perhaps some invalid configuration
>> > option/value, that will make "git gc" (most important) and "git
>> > reflog" (ideal, but less important) fail when they're run in our
>> > repositories? Hopefully at that point customers will reach out to us
>> > for help _before_ they corrupt their repositories.
>>
>> You could fix this and so many other issues by just hanging up a "Is
>> This Good For The Company?" banner up in Atlassian offices .
>
> Not sure I understand what this means, or what your goal was in saying
> it. No one inside Atlassian is running these commands. I'm trying to
> help save administrators from themselves, which reduces real world
> end-user pain that comes from decisions made without fully
> understanding the consequences. It feels like this comment is mocking
> my earnest desire to help, and my genuine question looking for any
> insight people more familiar with the code might be able to offer.
> Perhaps I'm just missing the joke, but if it's an Office Space
> reference it feels like it's in pretty poor taste.

I (mis)read 'administrators' as being other people at Atlassian. Yeah
it's a reference to Office Space. I meaning to poke some fun at the
situation of having to defensively configure tools least co-workers run
them the wrong way, which I'm sure we've all had to do at some point. I
didn't mean any offense by it.

>>
>> But more seriously:
>>
>>     $ stahp='Bryan.Turner.will.hunt.you.down.if.you.manually.run.gc' && git -c gc.pruneExpire=$stahp gc; git -c gc.reflogExpire=$stahp reflog expire
>>     error: Invalid gc.pruneexpire: 'Bryan.Turner.will.hunt.you.down.if.you.manually.run.gc'
>>     fatal: unable to parse 'gc.pruneexpire' from command-line config
>>     error: 'Bryan.Turner.will.hunt.you.down.if.you.manually.run.gc' for 'gc.reflogexpire' is not a valid timestamp
>>     fatal: unable to parse 'gc.reflogexpire' from command-line config
>
> Thanks for that! It looks like that does block both "git gc" and "git
> reflog expire" without blocking "git pack-refs", "git repack" or "git
> prune". Fantastic! The fact that it shows the invalid value means it
> might also be possible to at least provide a useful hint that manual
> GC is not safe.
>
> I appreciate your help, Ævar.

No problem. I was going to add that you can set
e.g. pack.windowMemory='some.message' to make this go for git-repack
too, but it sounds like you don't want that.

Is there a reason for why BitBucket isn't using 'git-gc'? Some other
hosting providers use it, and if you don't run it with "expire now" or
similarly aggressive non-default values on an active repository it won't
corrupt anything.