On 2011/05/15 18:22, Ted Unangst wrote: > On Sun, May 15, 2011 at 4:42 AM, Stuart Henderson <[email protected]> > wrote: > >> In one week, libpng is updated to version X+1 and firefox is updated > >> to version Z+1. You update. The gtk version has not changed, it will > >> not be upgraded. Now firefox is linked to png X+1 and X (via gtk). > >> Hilarity ensues. A newly built gtk will be linked against png X+1 and > >> will work correctly. > >> > >> Determining which package needs rebuilding is really hard. It's much > >> easier to install a complete matched set. > >> > >> > > > > Packages takes care of this just fine *but* you are supposed to > > use packages from a consistent snapshot. Don't just update a single > > package, make sure you 1) update packages as a complete set and > > 2) the mirror you're updating from isn't half-way through updating. > > They do? As far as I know, firefox will only say that it depends on > gtk Y and png X+1. Nothing records the fact that firefox depends on a > gtk Y that itself depends on png X+1.
If you update all packages from a consistent snapshot then this doesn't matter because the firefox and gtk packages will both depend on the same version of png.
