[Libguestfs] Plans for nbdkit 1.18 release?

[Richard W.M. Jones]

On Thu, Feb 20, 2020 at 05:03:18PM -0600, Eric Blake wrote:
> On 2/20/20 3:37 PM, Richard W.M. Jones wrote:
> >Hi Eric,
> >
> >nbdkit 1.16 was released over 3 months ago, and there has been quite a
> >lot of upstream development since then, so it could be about time for
> >a new stable release.  Anything in particular that you would like to
> >get in to 1.18?  Or anything we've added that you have reservations
> >about supporting long-term?
> 
> My biggest worry is whether we want to make python API version 2
> plugins support an optional flags parameter.  I think we decided
> that for version 1 plugins, making .zero's may_trim argument
> optional was not worth it.  But especially given that things like
> .pread currently always pass a flags=0 parameter, making it optional
> for API version 2 is still worth pursuing.  As you recall, I did
> post potential glue code for optional parameters, but it was
> different than the code we eventually took when adding API version 2
> support, and I have not yet had time to rebase the salvageable parts
> of my patches.

I think making the flags parameter option, ie this:

def pread(h, buf, offset, flags=0):
def trim(h, count, offset, flags=0):

could be worthwhile, although as you say below it we could still
change this later.  I don't think the bitmasks are bad, since plenty
of standard Python APIs seem to take bitmasks, and they're also much
faster to handle since they can be passed almost directly to the C
API.

> On the other hand, releasing 1.18 with mandatory flags= parameter in
> python plugins, and later relaxing it when we figure out the glue
> code, shouldn't be a problem.  It is not backwards incompatible to
> make a once-required parameter become optional.  So I don't see it
> as holding up a release.
> 
> My proposal to add an NBD_INFO_INIT_STATE extension is still pending
> on multiple fronts (approval at the NBD spec, and a rewrite of both
> qemu and nbdkit patches to address review comments); I'm not worried
> if that misses 1.18.

OK, thanks!  I'll have a go at some release notes next week which
should give us a clearer idea of what's new/changes.

Rich.

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