bug#10470: MSYS: race in directory access?

[Peter Rosin]

Stefano Lattarini skrev 2012-01-10 18:03:
>>> It would probably be worthwhile to try to understand why this is the case.
>>> As a wild guess, would this work?
>>>
>>>   - ( sleep 1 ) &
>>>   + sh -c "cd '$abs_builddir'; sleep 1" &
>>
>> No, fails in the same way as the original.
>>
> Sorry, by bad, I meant this:  sh -c "cd '$ac_abs_srcdir'; sleep 1"

No, that doesn't work either, at least not if you meant the line to end
with &, as it would be an inline sleep if it wouldn't.  Side note,
$ac_abs_srcdir is empty (so it's not really "somewhere/safe", as Eric
put it).

>>> We could enhance your original workaround like this:
>>>
>>>  am__remove_distdir = \
>>>    { test ! -d "$(distdir)" \
>>>      || { find "$(distdir)" -type d ! -perm -200 -exec chmod u+w {} ';' \
>>> -         && rm -fr "$(distdir)"; }; }
>>> +         && if rm -fr "$(distdir)"; then :; else \
>>> +## On MSYS (1.0.17) it is not possible to remove a directory that is
>>> +## in use; so, if the first rm fails, we sleep some seconds and retry,
>>> +## to give pending processes some time to exit and "release" the
>>> +## directory before we removed.  See automake bug#10470.
>>> +              sleep 5 && rm -fr "$(distdir)"; fi; }; }
>>>  am__post_remove_distdir = $(am__remove_distdir)
>>>  endif %?TOPDIR_P%
>>
>> This works, best so far!  Committable, if you ask me.
>>
> I agree, but first I'd like to see if we manage to resolve the issue into
> sanity.m4 itself.  If we fail, the above workaround will be good enough.

Yes, that would be best.  Otherwise we run the risk of having to add the
workaround for other places as well, ick.

I think (but I'm out on a limb here) that it might be the make process that
invoked the distcheck rule that lingers in the build-dir until configure
(and all its children terminates).  That make is locking the directory and
causes rm to fail. But as I said, I'm out on a limb and this is probably
just crap...

Cheers,
Peter