On Fri, Apr 25, 2014 at 11:37 AM, Philip Martin <philip.mar...@wandisco.com>wrote:
> Experimenting with gcc 4.9's -fsantize=undefined I got a warning: > > $ svnadmin create repo > $ svn mkdir -mm file://`pwd`/repo/A > ../src/subversion/libsvn_fs_fs/transaction.c:1978:14: runtime error: shift > exponent -1 is negative > > The code is > > 1976 /* We also don't want the linear deltification to span more > shards > 1977 than deltas would be used in the simple skip-delta schme. > */ > 1978 if ((1 << (--shards)) <= walk) > 1979 count = noderev->predecessor_count - 1; > The bug is that shards can be 0 to begin with. Any non-zero walk needs to start somewhere ... (and walk cannot be 0 here). > Perhaps something like this: > > Index: subversion/libsvn_fs_fs/transaction.c > =================================================================== > --- subversion/libsvn_fs_fs/transaction.c (revision 1589957) > +++ subversion/libsvn_fs_fs/transaction.c (working copy) > @@ -1975,7 +1975,7 @@ choose_delta_base(representation_t **rep, > > /* We also don't want the linear deltification to span more shards > than deltas would be used in the simple skip-delta schme. */ > - if ((1 << (--shards)) <= walk) > + if (shards > 0 && (1 << (--shards)) <= walk) > count = noderev->predecessor_count - 1; > } > I decided to fix the problem in the shards_spanned() function - see r1590383. Thanks for experimenting! -- Stefan^2.
