Re: maintainer mode parallel make issue

[Eric Blake]

Eric Blake <ebb9 <at> byu.net> writes:

> > Have you seen them on systems other than Cygwin?
> > How old is this Cygwin version?
> 
> Haven't tested other systems yet.  This was on cygwin 1.7 (still in beta), so 
> it could very well be a cygwin problem, although I am pretty sure that I have 
> also seen it on the latest stable cygwin 1.5.x.  I'll confirm.
> 
> > The above looks like XFile::lock fails to do its work.  We should have a
> > test that ensures that, in either Autoconf or Automake.
> 
> Indeed it is possible that some of the cygwin 1.7 improvements might be the 
> cause of XFile::lock behaving differently; if there is a way to trim this 
down 
> to a smaller test case, the cygwin developers would likely be able to 
> investigate it.

This indeed appears to be a bug in cygwin 1.7, although I don't know how to 
trim it into something simpler that I can report to the developers.  Repeated 
runs of 'touch ../configure.ac; make -j2' in the same VPATH build directory, 
with the same automake and autoconf versions, passed under cygwin 1.5 but 
failed under cygwin 1.7.  Some of the failures looked a bit different, but 
still look like a locking issue in autom4te.cache:

$ make -j2
CDPATH="${ZSH_VERSION+.}:" && cd .. && /bin/sh /home/eblake/m4/build-
aux/missing --run aclocal-1.10c -I m4
CDPATH="${ZSH_VERSION+.}:" && cd .. && /bin/sh /home/eblake/m4/build-
aux/missing --run autoconf
 cd .. && /bin/sh /home/eblake/m4/build-aux/missing --run automake-1.10c --gnu
/bin/sh ./config.status --recheck
running CONFIG_SHELL=/bin/sh /bin/sh ../configure -C CFLAGS=-gdwarf-2 -Wall 
CC=ccache gcc --enable-changeword --enable-silent-rules --no-create --no-
recursion
../configure: ../configure: cannot execute binary file
make: *** [config.status] Error 126
make: *** Waiting for unfinished jobs....
autom4te: cannot rename autom4te.cache/traces.1t as autom4te.cache/traces.1: No 
such file or directory
automake-1.10c: autoconf failed with exit status: 1
make: *** [../Makefile.in] Error 1

And when that particular failure mode happens, the broken configure differs as 
follows:

$ diff -au ../configure{.gold,} |cat -A
--- ../configure.gold^I2009-04-16 13:25:37.095406000 -0600$
+++ ../configure^I2009-04-16 13:26:51.093038000 -0600$
@@ -1,5 +1,4 @@$
-#! /bin/sh$
-# Guess values for system-dependent variables and create Makefiles.$
address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@#
 Guess values for system-dependent variables and 
create Makefiles.$

At any rate, I'll repeat this information to the cygwin developers, along with 
any ideas we have of how to trim it into a smaller testcase implicating just 
XFile::lock.

-- 
Eric Blake