Re: deprecation of in-tree builds

[Kevin Wolf]

Am 30.03.2020 um 15:42 hat Daniel P. Berrangé geschrieben:
> On Mon, Mar 30, 2020 at 02:31:52PM +0100, Peter Maydell wrote:
> > On Mon, 30 Mar 2020 at 14:26, Markus Armbruster <address@hidden> wrote:
> > >
> > > Peter Maydell <address@hidden> writes:
> > >
> > > > AIUI from Paolo, the intention is to deprecate and eventually
> > > > stop supporting "in-tree" builds, so that the only option is
> > > > building in a separate build directory. I thought we should
> > > > probably mention that in the 5.0 changelog, so I wrote up some
> > > > text:
> > > >
> > > > https://wiki.qemu.org/ChangeLog/5.0#Build_Information
> > >
> > > Overdue.  Thanks for doing this!
> > >
> > > > Suggestions for changes/comments etc welcome.
> > >
> > > Looks fine to me.
> > 
> > Consensus in the thread seemed to lean towards having
> > the 'configure/make' runes auto-create a build directory;
> > if we want to do that we should probably not say anything in
> > the release notes, because we'll cause people to change
> > unnecessarily. Or at least have them say "We recommend
> > out-of-tree builds. In future we might make the commands
> > that currently do an in-tree build automatically create
> > and use a build directory for you." rather than a blanket
> > "we're going to drop this and you should change what you
> > do now".
> > 
> > Thoughts?
> 
> When the time comes to switch to Meson, we'll be forcing a
> separate build directory & that will also potentially involve
> a change in build instructions for users.
> 
> So if we expect Meson will arrive in QEMU soon (say before end
> of this year), then I'd try to keep changes related to make to
> the bare minimum, and have Meson switch as the "flag day" when
> developers are forced to adapt their build process. 
> 
> IOW, merely warn people that in-tree builds are deprecated and
> not tested by the project and enourage switching to out of tree
> builds. Dont try to magically create a separate build dir now.

If manually dealing with separate build directories is inconvenient
today, it will still be inconvenient with Meson, so this would mean
introducing the automatic directly creation together with the other
changes to enable Meson. Which is fine by me, as long as it is really
done when the external directory becomes mandatory, so that people won't
have to switch back and forth between directories.

Kevin