Bug 928608 – kde-plasma/plasma-workspace-6.0.3 w/ -fno-delete-null-pointer-checks: /usr/include/qt6/QtWaylandClient/qwaylandclientextension.h:57:32: error: ‘(QtWayland::kde_output_order_v1::destroy != 0)’ is not a constant expression

• Status: UNCONFIRMED
• Product: Gentoo Linux

[Description jms 2024-04-05 00:54:28 UTC]

Created attachment 889475 [details]
build log

hi,
testing plasma 6 on a laptop,
using gentoo repository
unmasked using kde overlay keywords from
/var/db/repos/kde/Documentation/package.accept_keywords/kde-frameworks-6.0.keywords
/var/db/repos/kde/Documentation/package.accept_keywords/kde-plasma-6.0.keywords
/var/db/repos/kde/Documentation/package.accept_keywords/kde-gear-24.02.keywords
added -kf6compat /etc/portage/profile/use.mask 
kf6compat to global use

I can't get past kde-plasma/plasma-workspace-6.0.3

[Comment 1 jms 2024-04-05 00:55:53 UTC]

Created attachment 889476 [details]
emerge --info

[Comment 2 jms 2024-04-05 01:27:56 UTC]

I had done an emerge -pvuND @ world prior attempting to test plasma6.
I had plasma 5
emerge @world fail when trying to emerge plasma-workspace.

emerge -pvq =kde-plasma/plasma-workspace-6.0.3::gentoo 

[ebuild  NS   ] kde-plasma/plasma-workspace-6.0.3 [5.27.11] USE="calendar fontconfig (policykit) semantic-desktop wallpaper-metadata -appstream -debug -geolocation -gps -handbook -screencast* -systemd% -telemetry -test" 
[blocks B     ] kde-plasma/plasma-workspace:5 ("kde-plasma/plasma-workspace:5" is soft blocking kde-plasma/plasma-workspace-6.0.3)
[blocks B     ] kde-plasma/libkworkspace:5 ("kde-plasma/libkworkspace:5" is soft blocking kde-plasma/plasma-workspace-6.0.3)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (kde-plasma/plasma-workspace-5.27.11:5/5::gentoo, installed) pulled in by
    >=kde-plasma/plasma-workspace-5.27.11:5 required by (kde-plasma/plasma-meta-5.27.11:5/5::gentoo, installed) USE="bluetooth browser-integration crash-handler crypt cups desktop-portal display-manager elogind grub gtk kwallet legacy-systray networkmanager pulseaudio sddm smart wallpapers -accessibility -colord -discover (-firewall) -flatpak -handbook -plymouth -sdk -systemd -thunderbolt" ABI_X86="(64)"
    >=kde-plasma/plasma-workspace-5.27.11:5 required by (kde-plasma/plasma-browser-integration-5.27.11:5/5::gentoo, installed) USE="-debug" ABI_X86="(64)"
    >=kde-plasma/plasma-workspace-5.27.11:5[screencast?] (>=kde-plasma/plasma-workspace-5.27.11:5[screencast]) required by (kde-plasma/plasma-desktop-5.27.11:5/5::gentoo, installed) USE="kaccounts screencast semantic-desktop -debug -handbook -ibus -scim -test" ABI_X86="(64)"

  (kde-plasma/plasma-workspace-6.0.3:6/6::gentoo, ebuild scheduled for merge) pulled in by
    kde-plasma/plasma-workspace required by (virtual/notification-daemon-0:0/0::gentoo, installed) USE="kde -gnome" ABI_X86="(64)"
    =kde-plasma/plasma-workspace-6.0.3::gentoo

  (kde-plasma/libkworkspace-5.27.11:5/5::gentoo, installed) pulled in by
    >=kde-plasma/libkworkspace-5.27.11:5 required by (kde-plasma/khotkeys-5.27.11:5/5::gentoo, installed) USE="-debug -handbook" ABI_X86="(64)"
    >=kde-plasma/libkworkspace-5.27.11:5 required by (kde-plasma/plasma-desktop-5.27.11:5/5::gentoo, installed) USE="kaccounts screencast semantic-desktop -debug -handbook -ibus -scim -test" ABI_X86="(64)"
    >=kde-plasma/libkworkspace-5.27.11:5 required by (kde-plasma/powerdevil-5.27.11:5/5::gentoo, installed) USE="brightness-control wireless -caps -debug -handbook" ABI_X86="(64)"
    >=kde-plasma/libkworkspace-5.27.11:5 required by (kde-plasma/plasma-workspace-5.27.11:5/5::gentoo, installed) USE="calendar fontconfig (policykit) screencast semantic-desktop wallpaper-metadata -appstream -debug -geolocation -gps -handbook -telemetry -test" ABI_X86="(64)"

[Comment 3 jms 2024-04-05 03:03:35 UTC]

I wonder how I can have this;
In file included from [01m[K/usr/include/qt6/QtWaylandClient/QWaylandClientExtension:1[m[K,
                 from [01m[K/home/data/portagebuild/portage/kde-plasma/plasma-workspace-6.0.3/work/plasma-workspace-6.0.3/libkworkspace/outputorderwatcher.cpp

K/usr ?
K/home/ ?

[Comment 4 Andreas Sturmlechner 2024-04-06 17:22:28 UTC]

Hint:

> 57 |         if constexpr (destruct != nullptr) {
>    |                       ~~~~~~~~~^~~~~~~~~~

[Comment 5 Sam James 2024-04-06 17:26:09 UTC]

Please don't use options like -fno-delete-null-pointer-checks unless you're comfortable at least starting to debug failures that result (and able to identify they're related).

Now, as for the actual issue: this is curious because I wouldn't expect -fno-delete-null-pointer-checks to work like this, but I'm not an expert on how constexpr is evaluated. Arsen?

[Comment 6 jms 2024-04-06 21:59:24 UTC]

Many thanks 
to Andreas Sturmlechner and  Sam James 

I removed the  -fno-delete-null-pointer-checks and -mabm  so compile fine now.
I can not find a valid reason why I did put that here (quite  anold set-up).
As it's not something I should do.

[Comment 7 Arsen Arsenović 2024-04-07 11:23:44 UTC]

(In reply to Sam James from comment #5)
> Please don't use options like -fno-delete-null-pointer-checks unless you're
> comfortable at least starting to debug failures that result (and able to
> identify they're related).
> 
> Now, as for the actual issue: this is curious because I wouldn't expect
> -fno-delete-null-pointer-checks to work like this, but I'm not an expert on
> how constexpr is evaluated. Arsen?

hmm, this is odd, that value should be constexpr I think (given that its a template parameter and that it seems to be a function pointer).  a preprocessed unit would be nice because I couldn't hand-craft a reproducer

[Comment 8 Sam James 2024-04-07 16:30:03 UTC]

jms, could you run the failing gcc command manually in the build Dir but append -save-temps? Then upload outputorderwatcher.ii

[Comment 9 jms 2024-04-12 13:29:38 UTC]

Created attachment 890489 [details]
from portagebuild/portage/kde-plasma/plasma-workspace-6.0.3/work/plasma-workspace-6.0.3/libkworkspace

[Comment 10 jms 2024-04-12 13:30:49 UTC]

Created attachment 890490 [details]
from portagebuild/portage/kde-plasma/plasma-workspace-6.0.3/work/plasma-workspace-6.0.3/libkworkspace

[Comment 11 jms 2024-04-12 13:47:04 UTC]

Hi,
I changed in make.conf CFLAGS to:
CFLAGS="-march=skylake -O2 -pipe -fno-delete-null-pointer-checks -mabm -save-temps"
then did 
emerge -v1 =kde-plasma/plasma-workspace-6.0.3
and uploaded here files
outputorderwatcher.cpp
outputorderwatcher.h
found in 
portagebuild/portage/kde-plasma/plasma-workspace-6.0.3/work/plasma-workspace-6.0.3/libkworkspace/
Will that do?
Otherwise I am afraid you will have to be a bit more specific in your instructions.
the only experience I had of gcc was to try compiling a hello world ages ago...

[Comment 12 Sam James 2024-04-12 13:48:39 UTC]

I think the .i may be in portagebuild/portage/kde-plasma/plasma-workspace-6.0.3_build?

[Comment 13 jms 2024-04-12 14:09:20 UTC]

Created attachment 890492 [details]
outputorderwatcher.cpp.ii

found in portagebuild/portage/kde-plasma/plasma-workspace-6.0.3/work/plasma-workspace-6.0.3_build/libkworkspace/CMakeFiles/kworkspace.dir/

[Comment 14 Arsen Arsenović 2024-04-12 19:04:26 UTC]

thanks.  minimal reproducer:

template<auto foo = nullptr>
void
f()
{ if constexpr (foo != nullptr); }

struct some_class
{ void member(); };

void
g()
{
  f<&some_class::member>();
}

[Comment 15 Arsen Arsenović 2024-04-12 19:09:07 UTC]

seems to be https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100313 (thanks, andrew :-) )