Christian Couder [off-list ref] writes:
Your patch looks good. But there is also the problem that new bisect logs
will not be understood by old git. So I wonder if a patch to only read the
new log should be first commited to the "maint" branch.
I do not think it is worth it. If we are making something long lived like
rerere cache backward incompatible, the approach would be sensible, but
bisect log is about a single session and once you reached the breakage you
would not reuse it. Besides, the bisect log is designed to be executable
shell script so you can always copy it out, edit it if needed and feed
that to shell.