Helmut Grohne <hel...@subdivi.de> writes: > given the progress we have made with /usr-move and DEP17, I think it is > time to consider encoding the changes into policy. As of this writing, > there are 216 source packages in unstable that still install into > aliased locations and their number has been dropping since a while. All > but very few packages have bug reports of important severity and will > have their severity upgraded to serious on August 6th.
Thank you again for all the work that you have done on this. I agree that we have reached the point in the transition where we should update Policy to reflect the new requirements of the archive. > For these reasons, I propose changing section 10.1 and encoding the > avoidance of symlink vs directory conflicts into policy. To get a > discussion going, I suggest the following update. > - To support merged-/usr systems, packages must not install files in both > - /path and /usr/path. For example, a package must not install both > - /bin/example and /usr/bin/example. > + Since base-files implements mandatory merged-/usr by installing the > + aliasing symbolic links, other packages must not install files into > + aliased paths such as /bin, /lib, /lib* or /sbin. The package manager is > + not prepared to deal with such aliasing and in prohibiting the > + installation into aliased locations, we avoid triggering undefined > + behaviour. Conversely, packages may assume that /bin, /lib and /sbin are > + symlinks at all times and that their files below /usr/bin, /usr/lib and > + /usr/sbin are also accessible via their aliased locations. I spent some time thinking about this, since I personally still wish people wouldn't write /usr/bin/sh when they mean /bin/sh. I don't think Policy should prohibit this since, among other reasons, we have no effective enforcement mechanism and the package will clearly work fine on Debian systems. But it would be nice if people didn't gratuitously break portability, admittedly mostly to non-Linux systems at this point. That said, I think I convinced myself that this is just not something Policy can reasonably address. We should state the assumption as you stated it since that's required for packages to use /bin/sh at all, and this probably is not the place to give people portability advice, particularly since it only applies to things that might be copied from Debian to a non-Debian system and most of those aren't under our control and will never be written to Policy anyway. > Questions: > 1. Do you agree that policy should be changed? Yes. > If yes: > 2. Do you agree that policy should prohibit installing into aliased > paths? Yes. > 3. Do you agree that the current progress is sufficient for changing > policy? If not, when can we change policy? Yes. > 4. Do you agree with the proposed wording? Can you suggest > improvements? Yes. > 5. Given earlier disagreement on this matter, should we discuss this > matter in a wider setting such as d-devel? You certainly can, but at this late stage I don't think it would change anything. We're already into mass-bug-filing territory and it's going to be an RC bug, so it's already de facto policy and I don't see a justification for not making it de jure policy. -- Russ Allbery (r...@debian.org) <https://www.eyrie.org/~eagle/>
