Re: [PATCH v3 4/4] [NOT FOR MERGE] tests/qtest/migration: Adapt tests to use older QEMUs

[Peter Xu]

On Mon, Jan 15, 2024 at 10:45:33AM -0300, Fabiano Rosas wrote:
> > IMHO the n-1 tests are not for this.  The new FOO cap can only be enabled
> > in n+ versions anyway, so something like above should be covered by the
> > normal migration test that anyone would like to propose the new FOO cap.
> 
> You're being too generous in thinking new code will always restrict
> itself to implementing new functionality and never have a bug that
> affects a completly different part of the code. There could be an
> innocent refactoring along with cap FOO that breaks the migration only
> when FOO is enabled.

The question is even if we run cross-binary migration-test with current
version ("n") we can't detect such issue, right?  Because afaiu with that
we need to let migration-test always understand qemu versions, and it
should skip the new test that will enable FOO for cross-binary test since
it should detect the old binary doesn't support it.

> 
> But fine. We can't predict every scenario. Let's get this series out the
> door.
> 
> Thanks for the comments so far. I'll spin another version.

Yes if you think that is a good start point, we can start from simple.
That's so far the only solution I can think of that has mostly zero
maintanence burden for the tests meanwhile hopefully start to cover some
spots for us.  Said that, the discussion can keep going no matter what.

-- 
Peter Xu