> On April 28, 2015, 2:32 p.m., Rafael Schloming wrote: > > proton-c/src/object/map.c, line 266 > > <https://reviews.apache.org/r/33623/diff/2/?file=944061#file944061line266> > > > > This isn't related to this line, I just don't know where to put general > > comments... > > > > It occurs to me that with this sort of thing it is extremely valuable > > to capture an actual test case that reproduces the corruption. There are a > > number of existing tests for maps in proton-c/src/tests/object.c, but > > obviously they don't hit this delete scenario. It would be good to get some > > coverage of this case. If it would be helpful I can throw together a test > > class that lets you create objects consisting of an explicitly specified > > hashcode and value. That way you should be able to deterministically > > recreate the collisions resulting in this bug.
I agree. I'll have a look at the existing tests and see if I can create one demonstrating the problem with the current code. - Gordon ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/33623/#review81816 ----------------------------------------------------------- On April 28, 2015, 12:50 p.m., Gordon Sim wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/33623/ > ----------------------------------------------------------- > > (Updated April 28, 2015, 12:50 p.m.) > > > Review request for qpid, Alan Conway, Andrew Stitcher, and Rafael Schloming. > > > Bugs: PROTON-858 > https://issues.apache.org/jira/browse/PROTON-858 > > > Repository: qpid-proton-git > > > Description > ------- > > The internal map implementation for proton-c uses coalesced hashing, but the > current deletion algorithm does not take account of this. On deletion of > entries, the map can lose its ability to locate other entries by key. > > This patch is the simplest possible fix. It frees the deleted entry, makes > any previous entry that points to this tha tail of its chain, and then > relocates any entries in a chain following the deleted entry. Though I > believe this to be correct and safe, it does involve more work on some > deletions. The approach can be optimised further, either be reducing the > amount of chain that needs relocated, or by marking records as deleted in the > first instance and only rehashing later on some criteria. > > (I started off trying to do the latter, but it is more complicated and I > still haven't got my patch fully correct. When I get that working I'll post > that also. It is a more involved change though, so perhaps we may want to > consider this simpler approach for 0.9.1). > > > Diffs > ----- > > proton-c/src/object/map.c 1a758a1 > > Diff: https://reviews.apache.org/r/33623/diff/ > > > Testing > ------- > > > Thanks, > > Gordon Sim > >
