Re: maintainer mode parallel make issue

[Eric Blake]

Ralf Wildenhues <Ralf.Wildenhues <at> gmx.de> writes:

> > Yes, definitely.  And a testsuite addition to Autoconf or Automake to
> > ensure this would be good, I guess.
> 
> Proposed patch against Autoconf.  Tested on GNU/Linux and Cygwin: as it

cygwin 1.5.x, I presume?

> is, the patch hasn't caused a failure in several runs.  When I comment
> out the
>   $icache_file->lock (LOCK_EX);
> 
> line in bin/autom4te.in or go for a shared lock with LOCK_SH, rebuild,
> then the test has a fairly high chance of failing.

Your methods of testing seem sane.  I agree that using no lock or just LOCK_SH 
are insufficient to protect the second process from seeing modifications made 
while the first still owns the file.

> OK to apply?
> 
> Thanks,
> Ralf
> 
>     New test to ensure autom4te cache file locking works.
> 
>     * tests/tools.at (autom4te cache locking): New test.
>     Report by Eric Blake.

Yes, looks good to me.

-- 
Eric Blake