On Thu, Oct 06, 2022 at 12:33:22PM +0400, marcandre.lur...@redhat.com wrote: > From: Marc-André Lureau <marcandre.lur...@redhat.com> > > This is an alternative configure-time solution to "[PATCH] net: > print a more actionable error when slirp is not found". > > See also "If your networking is failing after updating to the latest git > version of QEMU..." ML thread. > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > --- > meson.build | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/meson.build b/meson.build > index 4321b8f8da..b05080b051 100644 > --- a/meson.build > +++ b/meson.build > @@ -690,6 +690,13 @@ if not get_option('slirp').auto() or have_system > endif > endif > > +# Remove this error after QEMU 8.1 has been released. > +if not get_option('slirp').disabled() and not slirp.found() > + error('libslirp is not explicitely disabled and was not found. ' + > + 'Since qemu 7.2, libslirp is no longer included as a submodule ' + > + 'fallback, you must install it on your system or --disable-slirp.') > +endif > +
I'm still not convinced we should be making this a fatal error, as opposed to treating it as a warning we display at the end of meson execution, which is what we do in other cases where we want to alert users to something important about their build environment. We have this for example: message() warning('SUPPORT FOR THIS HOST CPU WILL GO AWAY IN FUTURE RELEASES!') message() message('CPU host architecture ' + cpu + ' support is not currently maintained.') message('The QEMU project intends to remove support for this host CPU in') message('a future release if nobody volunteers to maintain it and to') message('provide a build host for our continuous integration setup.') message('configure has succeeded and you can continue to build, but') message('if you care about QEMU on this platform you should contact') message('us upstream at qemu-devel@nongnu.org.') This is just as important to show users as the slirp case IMHO, so it isn't clear why this approach is insufficient for slirp too. One irritation though, is that there's no way to get this text to display *after* meson prints the summary() data, so it is likely scrolled off the screen. I think 'summary()' ought to have a way to register warning messages that are guaranteed to be the last thing printed, with boldness. In absence of that, we can partially mitigate this by using a custom summary section though. Consider this: @@ -3936,3 +3937,20 @@ if not supported_oses.contains(targetos) message('if you care about QEMU on this platform you should contact') message('us upstream at qemu-devel@nongnu.org.') endif + +warning_info = {} + +# Remove this warning after QEMU 8.1 has been released. +if not get_option('slirp').disabled() and not slirp.found() + warning_info += {'SLIRP': 'libslirp not present, "user" network backend will not be available'} + message() + warning('libslirp not present, "user" network backend will not be available') + message() + message('Since qemu 7.2, libslirp is no longer included as a submodule') + message('fallback, you must install it on your system if you require') + message('-netdev user / -net user to be a supported network backend') + message() +endif + +summary(warning_info, bool_yn: true, + section: 'WARNINGS 💥 WARNINGS 💥 WARNINGS 💥 WARNINGS 💥 WARNINGS') Would mean that meson/configures ends with: Message: ../meson.build:3946: WARNING: libslirp not present, "user" network backend will not be available Message: Message: Since qemu 7.2, libslirp is no longer included as a submodule Message: fallback, you must install it on your system if you require Message: -netdev user / -net user to be a supported network backend Message: Build targets in project: 576 qemu 7.1.50 Directories Install prefix : /usr/local BIOS directory : share/qemu firmware path : share/qemu-firmware ...snip a page or two more summary... zstd support : YES 1.5.2 NUMA host support : YES capstone : YES 4.0.2 libpmem support : YES 1.11.1 libdaxctl support : YES 74 libudev : YES 250 FUSE lseek : YES selinux : YES 3.3 WARNINGS 💥 WARNINGS 💥 WARNINGS 💥 WARNINGS 💥 WARNINGS SLIRP : libslirp not present, "user" network backend will not be available Subprojects libvduse : YES libvhost-user : YES User defined options Native files : config-meson.cross prefix : /usr/local werror : true vfio_user_server : disabled Found ninja-1.10.2 at /usr/bin/ninja Running postconf script '/usr/bin/python3 /home/berrange/src/virt/qemu/scripts/symlink-install-tree.py' Is that really not sufficiently alerting to users that they might be loosing the 'user' network feature ? With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|