Bug#1100319: simgrid: FTBFS: /usr/include/ns3/attribute-accessor-helper.h:125:25: error: 'remove_cvref_t' in namespace 'std' does not name a template type

[Santiago Vila]

Package: src:simgrid
Version: 3.36-2
Severity: serious
Tags: ftbfs trixie sid

Dear maintainer:

During a rebuild of all packages in unstable, your package failed to build:

--------------------------------------------------------------------------------
[...]
[ 78%] Building CXX object 
CMakeFiles/simgrid.dir/src/kernel/resource/models/ns3/ns3_simulator.cpp.o
/usr/bin/c++ -DBOOST_CONTEXT_DYN_LINK -DBOOST_CONTEXT_NO_LIB 
-DBOOST_STACKTRACE_BACKTRACE_DYN_LINK -DBOOST_STACKTRACE_BACKTRACE_NO_LIB 
-Dsimgrid_EXPORTS -I/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/include 
-I/<<PKGBUILDDIR>>/include -I/usr -I/usr/include/libxml2 
-I/usr/include/python3.12 -I/usr/include/eigen3 
-I/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu -I/<<PKGBUILDDIR>> 
-I/<<PKGBUILDDIR>>/src/smpi/include -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. 
-fstack-protector-strong -fstack-clash-protection -Wformat 
-Werror=format-security -fcf-protection -Wdate-time -D_FORTIFY_SOURCE=2 -g3 
-Wundef -O3 -funroll-loops -fno-strict-aliasing  -finline-functions  
-ffile-prefix-map="/<<PKGBUILDDIR>>=.." -g -O2 
-ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong 
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection 
-Wdate-time -D_FORTIFY_SOURCE=2 -std=gnu++17 -flto=auto -fno-fat-lto-objects 
-fPIC -MD -MT 
CMakeFiles/simgrid.dir/src/kernel/resource/models/ns3/ns3_simulator.cpp.o -
 MF CMakeFiles/simgrid.dir/src/kernel/resource/models/ns3/ns3_simulator.cpp.o.d 
-o CMakeFiles/simgrid.dir/src/kernel/resource/models/ns3/ns3_simulator.cpp.o -c 
/<<PKGBUILDDIR>>/src/kernel/resource/models/ns3/ns3_simulator.cpp
In file included from /usr/include/ns3/attribute-helper.h:12,
                 from /usr/include/ns3/address.h:14,
                 from /usr/include/ns3/net-device.h:12,
                 from /usr/include/ns3/node.h:12,
                 from 
/<<PKGBUILDDIR>>/src/kernel/resource/models/ns3/ns3_simulator.hpp:12,
                 from 
/<<PKGBUILDDIR>>/src/kernel/resource/models/ns3/ns3_simulator.cpp:6:
/usr/include/ns3/attribute-accessor-helper.h:125:25: error: 
‘remove_cvref_t’ in namespace ‘std’ does not name a template type
  125 |     using Result = std::remove_cvref_t<T>;
      |                         ^~~~~~~~~~~~~~
/usr/include/ns3/attribute-accessor-helper.h:125:20: note: 
‘std::remove_cvref_t’ is only available from C++20 onwards
  125 |     using Result = std::remove_cvref_t<T>;
      |                    ^~~
In file included from /usr/include/ns3/wifi-phy.h:14,
                 from /usr/include/ns3/wifi-helper.h:19,
                 from /usr/include/ns3/spectrum-wifi-helper.h:12,
                 from /usr/include/ns3/wifi-module.h:7,
                 from 
/<<PKGBUILDDIR>>/src/kernel/resource/models/ns3/ns3_simulator.hpp:15:
/usr/include/ns3/wifi-phy-operating-channel.h:39:10: error: declaration of 
‘operator<=’ as non-function
   39 |     auto operator<=>(const FrequencyChannelInfo& info) const = default;
      |          ^~~~~~~~
/usr/include/ns3/wifi-phy-operating-channel.h:39:18: error: expected ‘;’ at 
end of member declaration
   39 |     auto operator<=>(const FrequencyChannelInfo& info) const = default;
      |                  ^~
      |                    ;
/usr/include/ns3/wifi-phy-operating-channel.h:39:20: error: expected 
unqualified-id before ‘>’ token
   39 |     auto operator<=>(const FrequencyChannelInfo& info) const = default;
      |                    ^
make[4]: *** [CMakeFiles/simgrid.dir/build.make:4884: 
CMakeFiles/simgrid.dir/src/kernel/resource/models/ns3/ns3_simulator.cpp.o] 
Error 1
make[4]: Leaving directory '/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu'
make[3]: *** [CMakeFiles/Makefile2:3804: CMakeFiles/simgrid.dir/all] Error 2
make[3]: Leaving directory '/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu'
make[2]: *** [Makefile:169: all] Error 2
make[2]: Leaving directory '/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu'
dh_auto_build: error: cd obj-x86_64-linux-gnu && make -j1 "INSTALL=install 
--strip-program=true" all tests manpages VERBOSE=1 returned exit code 2
make[1]: *** [debian/rules:50: override_dh_auto_build] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:33: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2
--------------------------------------------------------------------------------

The above is just how the build ends and not necessarily the most relevant part.
If required, the full build log is available here:

https://people.debian.org/~sanvila/build-logs/202503/

About the archive rebuild: The build was made on virtual machines from AWS,
using sbuild and a reduced chroot with only build-essential packages.

If you could not reproduce the bug please contact me privately, as I
am willing to provide ssh access to a virtual machine where the bug is
fully reproducible.

If this is really a bug in one of the build-depends, please use
reassign and add an affects on src:simgrid, so that this is still
visible in the BTS web page for this package.

Thanks.