Re: [kernelci-members] Working with the KernelCI project

Dmitry Vyukov
2020-10-01T08:43:31Z

On Thu, Oct 1, 2020 at 10:30 AM Nikolai Kondrashov
<Nikolai.Kondrashov@redhat.com> wrote:
>
> On 9/30/20 10:07 AM, Dmitry Vyukov wrote:
> > On Tue, Sep 29, 2020 at 7:13 PM Nikolai Kondrashov
> > <Nikolai.Kondrashov@redhat.com> wrote:
> >> Regarding bisection results I was hoping we could represent that data
> >> implicitly. I.e. by having information about which 'revision' comes after
> >> which, and executing a query to find a pair of adjacent revisions one of which
> >> has the bug and another doesn't. In theory that should be possible, but in
> >> practice... well, you know :) If that fails, we can attach that data
> >> explicitly somewhere. Or we can simply start with that to have it faster.
> >
> > Humm... interesting. I guess it can work. We could mark the issue as
> > happening on the cause commit and as not happening on the previous
> > commit.
> > However, one problem is that we don't keep info about the previous
> > commit as of now, we only store the root cause commit in the database.
>
> Something has to maintain the information on history connectivity, and so far
> the plan was to let the submitting system do it. E.g. refer to a clone of the
> repo they're testing. There's definitely more research and design to be done.
>
> However, you should've been testing the previous commit to be able to find the
> root cause commit? Shouldn't you?

We do. But that happens in a very different part of the system and
that info is not kept in a structured form because it's not useful for
anything in our system.

Well, it actually turned out that it's not necessary to test all of
the parents of a commit during bisection to point at a particular
commit in some interesting git tree topologies.

> > Another is that in git it's possible to have several preceding
> > commits.
>
> Right, I didn't think through that yet. We might need a separate history link
> object, then. Do you know if a commit can have more than two parents?

Octopus merge commits can have lots of parents.