pkg/41143: pkg_add -u doesn't record inverse dependencies

[rillig%NetBSD.org@localhost]

>Number:         41143
>Category:       pkg
>Synopsis:       pkg_add -u doesn't record inverse dependencies
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 05 08:15:00 +0000 2009
>Originator:     Roland Illig
>Release:        Linux 2.6
>Organization:
>Environment:
>Description:
In a new, clean pkgsrc installation, I did the following:

$ pkg_add pkglint-4.87.tgz
[...]
$ pkg_delete -r perl
[...]

This did exactly what I expected. Then, I did:

$ pkg_add pkglint-4.87.tgz
[...]
$ pkg_add -u pkglint-4.91.tgz
[...]
$ pkg_delete -r perl
[...]

Now, pkglint is still installed, but all its dependencies are gone. This is 
because "pkg_add -u" removed the old dependency (pkglint-4.87) from 
p5-Digest-SHA1/+REQUIRED_BY, but didn't add the new dependency (pkglint-4.91).
>How-To-Repeat:

>Fix: