Bug#848060: libx11-protocol-other-perl: FTBFS randomly (failing tests)

[tony mancill]

Hi Gregor,

On Thu, Dec 22, 2016 at 05:53:21PM +0100, gregor herrmann wrote:
> 
> I can reproduce the failure by running the test in a loop in the
> chroot [0]; sometimes in the first low-single-digit round, sometimes a
> bit later.
> 
> Interestingly, higher load on the machine seems to make
> the failure go away (mostly we see the opposite). But this might as
> well be a false guess.

Sounds like a classic race condition - just in this case winning the
race means the test fails?

> Reading through t/XSetRoot.t is interesting:
> 
> 
> # Something fishy with xvfb test server seems to cause the reconnect below
> # to fail.  Keeping a second connection makes it better.  Dunno why.
> #
> my $keepalive_X = X11::Protocol->new ($display);
> 
> No idea what exactly is going on here, but I note the coincidence of
> tha author mentioning xvfb and we running xvfb and the failure
> exactly at this point (i.e. after the diagnostic output and before
> the first actual test).
> 
> Commenting out the line seems to trigger the failure earlier.
> Adding yet another connection seems to push the failure further back.
> Dropping this second object and adding a sleep(1) after the keepalive
> and before the tests (is ugly and) seems to workaround the problem.
> Interestingly, the diag output mentions "# DISPLAY :99" and "# DISPLAY
> :100" alternating.
> Ah, and now I triggered a failure even with the sleep(1).
> 
> 
> So ... I'm not sure. It looks like this test has known problems with
> xvfb, and this doesn't show a problem in the code.
> In line with our handling of similar fragile tests, I propose to
> disable it.

100% agreed.  clusterssh and shutter are the only r-deps for this
package, so I feel confident with this course of action.

> Done in git, waiting with an upload for further comments.

I reviewed your commits and they look good to me.  Also, thank you for
providing a much quicker way to run the tests than a full package build
(although I still haven't reproduced it - I guess my machine is always
too slow... :).

Thank you both for your efforts on this.
tony
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