Re: [PATCH] t5570: drop racy test

[Thomas Gummerer <t.gummerer@gmail.com>]

On 12/21, Johannes Schindelin wrote:
> Hi Thomas & Peff,
> 
> On Thu, 20 Dec 2018, Jeff King wrote:
> 
> > On Thu, Dec 20, 2018 at 04:41:50PM +0000, Thomas Gummerer wrote:
> > 
> > > Dscho also mentioned on #git-devel a while ago that he may have a look
> > > at actually making this test race-proof, but I guess he's been busy
> > > with the 2.20 release.
> 
> And GitGitGadget. And working on the Azure Pipelines support. And
> mentoring two interns.
> 
> This is what I still have in my internal ticket:
> 
> 	Try to work around occasional t5570 failures in Git's test suite
> 
> 	Seems that there is a race condition in
> 	https://github.com/git/git/blob/master/t/lib-git-daemon.sh#L48-L69
> 	that could possibly be solved by writing to the daemon.log
> 	directly, and showing the output only via `tail -f` (and only when
> 	running in verbose mode, as it simply won't make sense otherwise).
> 
> However, if the preferred route is to go ahead and just remove that test
> altogether, I'm fine with that, too.

Right, I was of course completely unaware of that internal ticket.  If
you still want to go that way there are certainly no objections from
me.  I just want to make sure not more users run into this racyness,
and I guess you also may have more important/interesting things to
work on.

> The only reason, in my mind, why we still have `git-daemon` is that it
> allows for easy standing up your own Git server, e.g. as an ad-hoc way to
> collaborate in a small ad-hoc team. If we ever get to the point where we
> can stand up a minimal HTTP/HTTPS server with an internal Git command (not
> requiring sysadmin privileges), from my point of view `git-daemon` can
> even go the way of the Kale Island (but for much better reasons [*1*]).
> 
> > > I'm also not sure it's worth spending a lot of time trying to fix this
> > > test, but I'd definitely be happy if someone proposes a different
> > > solution.
> > 
> > Yeah. I'm sure it's fixable with enough effort, but I just think there
> > are more interesting and important things to work on.
> > 
> > > --- >8 ---
> > > Subject: [PATCH] t5570: drop racy test
> > 
> > So yeah, I'm still fine with this. But...
> > 
> > > ---
> > >  t/t5570-git-daemon.sh | 13 -------------
> > >  1 file changed, 13 deletions(-)
> > 
> > This is the only user of daemon.log, so we could drop those bits from
> > lib-git-daemon.sh, too. That would also prevent people from adding new
> > tests, thinking that this was somehow not horribly racy). I.e.,
> > reverting 314a73d658 (t/lib-git-daemon: record daemon log, 2018-01-25).

Right that makes sense.  I sent that as patch 2/1, but I'm happy to
squash those into one if that's preferred.

> Indeed, that would be good.
> 
> The only reason to keep daemon.log that I can think of is to make
> debugging easier, but then, if it should become necessary, it is probably
> easier to freopen() stdout or stderr into a file in `git daemon`, anyway.

We do still print the output when tests are run in verbose mode, which
should be just as good as having the log in a separate file in most
cases I suspect.

> Ciao,
> Dscho
> 
> Footnote *1*: Kale Island, along with Rapita, Rehana, Kakatina and Zollies
> is prominently featured in a scientific article at
> http://iopscience.iop.org/article/10.1088/1748-9326/11/5/054011 that is on
> my "important papers I read in 2018" list.