On Mon, Feb 8, 2010 at 4:29 PM, <fons@xxxxxxxxxxxxxxx> wrote: > On Mon, Feb 08, 2010 at 03:47:47PM -0600, Aaron Griffin wrote: > >> When I attempt to install app-baz, which pulls in libfoo 2.0, how do >> you expect to resolve all the conflicts that result from keeping >> libfoo 1.0 on the system at the same time as libfoo 2.0? All sorts of >> things are in conflict here. There's no way to automatically cover >> these cases that I can see > > There are no conflicts resulting form doing this. > > Suppose I have a fresh install with: > (-> means a symlink) > > libfoo.so -> libfoo.so.1.2.3 > libfoo.so.1 -> libfoo.so.1.2.3 > libfoo.so.1.2.3. // the actual library > > and all apps have been linked to libfoo.so.1 > > When the library is updated as the result of > e.g. installing a new package (and meanwhile > the library version for the whole repo has > changed) there are two possible scenarios: > > > 1. Bugfix, security update or small enhancement: > the library is fully compatible with the previous > one and has the same major version number. The > result is e.g.: > > libfoo.so -> libfoo.so.1.3.5 > libfoo.so.1 -> libfoo.so.1.3.5 > libfoo.so.1.3.5. // the actual library > > All apps use the new version. > > > 2. A new major version of the library (very > probably incompatible). The result is: > > libfoo.so -> libfoo.so.2.1.1 > libfoo.so.1 -> libfoo.so.1.2.3 > libfoo.so.1.2.3. // the actual library > libfoo.so.2 -> libfoo.so.2.1.1 > libfoo.so.2.1.1. // the actual library > > So pacman has installed libfoo.so.2.1.1, created > the symbolic link to it from libfoo.so.2, and > modified the symbolic link from libfoo.so to > point to the new version. > > The result of this is that: > > 1. The newly installed package will use the > new library as it expects 'libfoo.so.2'. > > 2. The other applications will continue to use > the old version, as they expect 'libfoo.so.1'. > In other words they will still work. A smart > user will probably update them soon, but is > not forced to do this immediately. > > 3. Recompiling anything locally will use the > new version as during compilation you use > the name 'libfoo.so' without version number, > which, using the symbolic link, gets coded > into the binary as 'libfoo.so.2'. > > *** There is no conflict. *** Pacman can forget > about and even delete the package that supplied > the old version. It just *should not remove the > old library itself*. > > The system with major/minor version numbers and > the symbolic links is actually designed to be > used like this, and to permit different versions > to co-exist on a system. A package is not a single .so file, unless that is your proposal - to split all .so files into their own packages. Here is a list of files that would conflict if this was done with libpng: libpng /usr/bin/libpng-config libpng /usr/bin/libpng12-config libpng /usr/bin/png2pnm libpng /usr/bin/pnm2png libpng /usr/include/libpng12/png.h libpng /usr/include/libpng12/pngconf.h libpng /usr/include/png.h libpng /usr/include/pngconf.h libpng /usr/lib/pkgconfig/libpng.pc libpng /usr/lib/pkgconfig/libpng12.pc libpng /usr/share/licenses/libpng/LICENSE libpng /usr/share/man/man3/libpng.3.gz libpng /usr/share/man/man3/libpngpf.3.gz libpng /usr/share/man/man5/png.5.gz
