Re: [Qemu-devel] [PATCH-for-2.9] replay/replay.c: bump REPLAY_VERSION

["Alex Bennée" <alex.bennee@linaro.org>]

Eric Blake <eblake@redhat.com> writes:

> On 03/24/2017 10:26 AM, Alex Bennée wrote:
>> A previous commit (3d4d16f4) added support for audio record/playback.
>> However this breaks the logfile ABI due to the re-ordering of the
>> ReplayEvents enum. The REPLAY_VERSION check is meant to prevent you
>> from using old log files in newer QEMUs but this is currently broken.
>
> As we don't have a formal release with the reordered enum yet, would an
> alternative approach be partially reverting 3d4d16f4 to instead stick
> the new enum values at the end, so that all existing enums are in the
> same order?

That would certainly be an option.

> Or do you still need the version bump even then, because
> you don't want a new stream (with the new enums) being played to an
> older system that isn't expecting them?

I'm not personally bothered either way. Currently the check is a simple
match so there is not really the concept of a super/subsets of log file.

I only ran into this as I was trying to debug the record/replay
regression while writing a dumper script to debug the current
regression:

  https://github.com/stsquad/qemu/blob/mttcg/more-fixes-for-rc1-v2/scripts/replay-dump.py

--
Alex Bennée