Branko Čibej wrote on Mon, Dec 10, 2012 at 11:51:08 +0100: > On 10.12.2012 11:31, Daniel Shahaf wrote: > > Branko Čibej wrote on Mon, Dec 10, 2012 at 00:26:20 +0100: > >> On 10.12.2012 00:08, Johan Corveleyn wrote: > >>> On Sun, Dec 9, 2012 at 11:43 PM, Daniel Shahaf <[email protected]> > >>> wrote: > >>>> Johan Corveleyn wrote on Sun, Dec 09, 2012 at 21:15:24 +0100: > >>>>> 2) Am I the only one who wants to protect his repository against this > >>>>> corruption? Judging from [1], I don't think so. It doesn't make sense > >>>>> that everyone starts writing this pre-commit hook, for something that > >>>>> IMHO is an obvious anti-corruption protection. I think every > >>>>> repository out there deserves to be protected against this. > >>>>> > >>>> FWIW, I suggested a hook because you could implement that in about > >>>> 5 minutes, whereas doing a C code change would take at least 10 times > >>>> that (and several weeks if you have to wait for it to appear in a 1.7.x > >>>> release that you can install at $WORK). I won't object to C code > >>>> verifying the svn:eol-style invariant. > >>> Thanks. And your pre-commit hook example is much appreciated. > >>> > >>> For the moment I get the impression that it's not really doable / > >>> desirable to implement this in the repository. At least until now > >>> no-one has suggested how it could be done, and I don't know enough > >>> myself about the server-side / back-end to figure it out :-). > >> The first obstacle is that the server does not interpret properties.[1] > >> Therefore, you'd have to implement this check at transaction-commit > >> time, because there's no earlier point where you're guaranteed to have > >> all node properties at their final values. This implies that the time to > >> reject a commit would be proportional to the size of the commit (which > >> isn't the case when it comes to conflict detection). > > Can't you do what stefan2 suggested, but in libsvn_repos? The repos > > layer commit editor would remember for each file whether its textdelta > > has added a new 0x0D byte, then at close_edit() it would iterate all > > files in the commit --- and for each file only compare its svn:eol-style > > property to the by-now-precomputed "did it it contain a 0x0D" bit. > > > > I'm not sure how efficient it would be to parse for 0x0D's in > > libsvn_repos, though. Maybe we should make this optional. > > > It's not enough to just look for \r in the delta stream. Certainly > wouldn't help with historically broken files.
I wasn't trying to fix historically broken files. (That would require a fulltext scan --- that's not a cheap computation.) Do you see another problem? > Maybe that's a good idea, but /why/ put it in libsvn_repos when it's > much easier and cleaner to just provide some standard hooks, written in > C and distributed with releases, that the admin plug in if she feels > like it? Surely that's what hooks are for. The argument is that a Subversion server should be enforcing Subversion's invariants. That said, I'm not opposed to doing it via standard hooks. It's a good way to introduce the feature in a way that allows more easily changing it before it hits the APIs and their strict compatibility rules. > > > -- Brane > > > -- > Branko Čibej > Director of Subversion | WANdisco | www.wandisco.com >
