I can have negative dependencies, look at the packaging/debian/control file. But if I build-conflicted on bison, then pike wouldn't get built - because there can be only one bison version installed on the system (actually, it is possible to have many versions - like autoconf which is in two flavors in Debian or automake which is in 3 flavors or pike in two flavors as well) but in this case it wouldn't make much sense since bison was undoubtedly buggy. Actually, the debian dependencies system is very powerful - if you have some time, read up about it on http://debian.org/devel/ in the Packaging section.
/ Marek Habersack (Grendel)
Previous text:
2002-10-18 20:10: Subject: Pike 7.2 (latest CVS) and GNU bison 1.50 - no go...
So you can't have a negative dependency on certain versions of software? If not it really sounds like a non-working package system. There is not much software that gets steadily better without new bugs and compatibility issues. Roxen, Pike, caudium, gcc, autoconf to name a few.
/ Martin Nilsson (Fake Build Master)