Re: What's cooking in git.git (Apr 2019, #01; Thu, 4)

[Josh Steadmon <steadmon@google.com>]

On 2019.04.08 13:28, Junio C Hamano wrote:
> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> 
> > unique (AFAICT "actually unique" in practice) in the parallel in-flight
> > jh/trace2-sid-fix
> > (https://public-inbox.org/git/4352952677a11776a18ec9b6862cf358307cfafd.1553879063.git.gitgitgadget@gmail.com/)
> >
> > I think it's fine to merge js/trace2-to-directory down as it is, but do
> > you/Josh think that retry logic needs to stay with that sort of SID?
> 
> I do not speak for Josh, but I think the only two logical choices
> are to open with (O_CREAT|O_EXCL) and
> 
>  (1) fallback with .%d suffix, making it clear that we are not
>      willing to lose log files even when SID generation is botched; or
> 
>  (2) die/BUG when it fails, making it clear that we do rely on the
>      guanateed uniqueness of SID.
> 
> A distant third may be to warn when open with O_CREAT|O_EXCL fails,
> but I am not sure what its value would be to do so---especially if
> we trust in the "actually unique in practice".  Between (1) and (2),
> I have a slight preference to (1) over (2), as that is much easier
> to explain.
> 
> Those who want to have a "fixed width" thing could just ignore the
> ones with suffix---as long as the "actually unique in practice"
> claim holds, doing so will not lose any non-negligible amount of
> information anyway.

I prefer (1) as well, although I would be happy to re-write this if the
list consensus goes the other way.