On 11/17/2016 05:37 PM, Guido Günther wrote:
I'm basically fine with all of this (but did not du any actual testing)
Cool.
but we should not warn if the user/group already exists (even with the wrong uid). Otherwise we'd warn over and over again, we don't want to force users to change existing installations.
Actually the warning is not repeated; the answer is saved by debconf. If you just install/upgrade after having answered the question once, it doesn't show up. You only get it again in intentional cases: 1) dpkg-reconfigure 2) apt-get purge && re-install 3) remove its 'Flags: seen' line from /var/cache/debconf/config.dat
If we want to notify users of existing installations we have a Debian.NEWS for this that can explain that switching to uid/git 64055 is recommended.
Good point. I can write a snippet for that too if you want, but not sure it's enough depending on your decision about how/when to notify users (paragraph below).
IMHO the only important case to warn about is the case where user or group does not yet exist _and_ the uid/gid is already taken by another user or group. What do you think?
Well, I still think it's also important to warn when the user/group already exists (with a different uid/gid). The main reason is to help users not to hit a known problem, and help maintainers not to get unnecessary bug reports, or having to debug it again (it was hard to debug/trace this, the root cause is very subtle, and the stack components pile up -- I ended up strace'ing qemu, found EACCES in read/write syscalls, and had to understand how NFS had come up with this type of error -- not that I'm proud, I imagine it's easy for people more experienced w/ the virtualization stack; just a story). If existing installations are never told about this, they didn't even have a chance to try to fix their environment not to hit it, and I guess it's a valid expectation from the packages to set up things up correctly so not to hit problems (of course this case is not easy/automatic to resolve..) (some systems will never hit it because users were just created in the same order on source/destination hosts; but that's luck) On the other hand, I'm not sure how disruptive such a warning is for automated deployments/upgrades, specially because the default is to abort the install (perhaps we should change it). Anyway, just trying to provide some pondering and other thoughts/ views on the matter, with the intention it may help :- ) Let me know what/how you'd like it in the patches and I'll spin v3 ;- )
Thanks a lot for working on this!
Glad to contribute; thanks for the great suggestions/pointers. -- Mauricio Faria de Oliveira IBM Linux Technology Center
