Re: [libvirt] [PATCHv3 00/13] Switch from yajl to Jansson

On Tue, May 15, 2018 at 05:24:40PM +0100, Daniel P. Berrangé wrote: > On Tue, May 15, 2018 at 06:12:05PM +0200, Andrea Bolognani wrote: > > On Fri, 2018-05-11 at 14:59 +0200, Ján Tomko wrote: > > > Per the discussion here: > > > https://www.redhat.com/archives/libvir-list/2017-November/msg00225.html > > > Switch from using yajl to Jansson. > > > > I tried building > > > > https://repo.or.cz/libvirt/jtomko.git/ jansson > > > > on all platform libvirt supports. > > > > Debian 8, Ubuntu 14.04 and Ubuntu 16.04 all linked successfully > > against Jansson, but when running the test suite I got > > > > FAIL: virnetdaemontest > > FAIL: qemumonitorjsontest > > FAIL: qemucapabilitiestest > > FAIL: qemuhotplugtest > > FAIL: qemucommandutiltest > > FAIL: qemublocktest > > FAIL: qemumigparamstest > > FAIL: virjsontest > > > > >From a quick look, it seems like at least some of the failures > > are caused by dictionaries and arrays having their members > > shuffled around. > > When using YAJL, object properties are stored in arrays, so order is > stable when printing. > > With Jansson, object properties appear to be stored in hash tables, > so order is potentially unstable when printing. > > I'm a little surprised it doesn't fail on all platforms - makes me > wonder how good the hash function is. > > Looks like we would need JSON_SORT_KEYS to json_dumps(), but that > may well require all test data to be recreated :-( > There is a JSON_PRESERVE_ORDER flag since v1.3 that formats the keys in the same order they were added and it's the default since 2.8.

I have pushed a patch that uses it on my repo: https://repo.or.cz/libvirt/jtomko.git/ jansson_preserve