Random pkg_rolling-replace failure in "creating binary packages" step

[Sverre Froyen <sverre%viewmark.com@localhost>]

Hi,

I often utilize "pkg_rolling-replace -u" to upgrade installed packages. 
Recently, I have started to see occasional failures like in this example 
(upgrading www/http_load from nb2 to nb3)

...
=> Automatic manual page handling
=> Creating binary package 
/usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz
===> Replacing for http_load-20060312nb3
WARNING: experimental target - DATA LOSS MAY OCCUR.
Creating binary package: http_load-20060312nb2
Creating package /usr/pkgsrc/www/http_load/work/http_load-20060312nb2
===> Updating using binary package of http_load-20060312nb3
/usr/pkg/sbin/pkg_add -K /var/db/pkg -U -D 
/usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz
RR> Packaging http_load-20060312nb3
=> Bootstrap dependency digest>=20010302: found digest-20121220
===> Building binary package for http_load-20060312nb3
=> Creating binary package /usr/pkgsrc/packages/All/http_load-20060312nb3.tgz
/bin/ln -f /usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz 
/usr/pkgsrc/packages/All/http_load-20060312nb3.tgz 2>/dev/null ||  /bin/cp -pf 
/usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz 
/usr/pkgsrc/packages/All/http_load-20060312nb3.tgz
cp: /usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz: No such 
file or directory
*** Error code 1

The "Creating binary package 
/usr/pkgsrc/www/http_load/work/.packages/http_load-20060312nb3.tgz" step must 
succeed because the pkg_add step works and the new version of http_load is in 
fact installed,

$ pkg_info | grep http_load
http_load-20060312nb3 Multiprocessing http test client

The "Creating binary package 
/usr/pkgsrc/packages/All/http_load-20060312nb3.tgz" step fails, however, 
because the .packages directory is empty (as the error message indicates and an 
examination of the directory shows).

I first noticed this on a Mac OSX 10.8 and assumed it was a quirk in the Mac 
pkgsrc setup. However, now I also see it on NetBSD 6.1 amd64. There *may* be a 
timing issue because it happens only for an apparently random subset of the 
packages that are being replaced.

Has anyone else seen this? Any suggestions on how to track down the problem?

Thanks,
Sverre