Error when compiling Hana according to "How to contribute"

[Aster89]

I've followed steps 1, 2, and 4 (not 3) from How to contribute, but I get this error:

Scanning dependencies of target test.string.zero
[  2%] Building CXX object test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o
In file included from /home/enrico/hana/include/boost/hana/string.hpp:13,
                 from /home/enrico/hana/test/string/zero.cpp:7:
/home/enrico/hana/include/boost/hana/fwd/string.hpp:268:24: error: ISO C++ did not adopt string literal operator templates taking an argument pack of characters [-Werror=pedantic]
  268 |         constexpr auto operator"" _s();
      |                        ^~~~~~~~
In file included from /home/enrico/hana/test/string/zero.cpp:7:
/home/enrico/hana/include/boost/hana/string.hpp:117:24: error: ISO C++ did not adopt string literal operator templates taking an argument pack of characters [-Werror=pedantic]
  117 |         constexpr auto operator"" _s() {
      |                        ^~~~~~~~
cc1plus: note: unrecognized command-line option ‘-Wno-self-assign-overloaded’ may have been intended to silence earlier diagnostics
cc1plus: all warnings being treated as errors
make[3]: *** [test/CMakeFiles/test.string.zero.dir/build.make:82: test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o] Error 1
make[2]: *** [CMakeFiles/Makefile2:13422: test/CMakeFiles/test.string.zero.dir/all] Error 2
make[1]: *** [CMakeFiles/Makefile2:1622: CMakeFiles/check.dir/rule] Error 2
make: *** [Makefile:337: check] Error 2

My compiler is

$ g++ --version 
g++ (GCC) 10.2.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

which looks ok, based on General notes on compiler support.

[ricejasonf]

The compile-time string user defined literal is a GNU extension. It appears the -pedantic flag is causing this to be an error.

BOOST_HANA_CONFIG_ENABLE_STRING_UDL should probably not be set if BOOST_HANA_HAS_PEDANTIC is set.

Are you manually defining either of those?

EDIT: The input cli command would be helpful (via VERBOSE=1 make test.string.zero).

[Aster89]

No, I'm not setting those. Both the commands below print does not exist in Bash:

echo ${BOOST_HANA_HAS_PEDANTIC-does not exist}
echo ${BOOST_HANA_CONFIG_ENABLE_STRING_UDL-does not exist}

Here's the output of VERBOSE=1 make test.string.zero:

/usr/bin/cmake -S/home/enrico/hana -B/home/enrico/hana/build --check-build-system CMakeFiles/Makefile.cmake 0
make  -f CMakeFiles/Makefile2 test.string.zero
make[1]: Entering directory '/home/enrico/hana/build'
/usr/bin/cmake -S/home/enrico/hana -B/home/enrico/hana/build --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/cmake -E cmake_progress_start /home/enrico/hana/build/CMakeFiles 0
make  -f CMakeFiles/Makefile2 test/CMakeFiles/test.string.zero.dir/all
make[2]: Entering directory '/home/enrico/hana/build'
make  -f test/CMakeFiles/test.string.zero.dir/build.make test/CMakeFiles/test.string.zero.dir/depend
make[3]: Entering directory '/home/enrico/hana/build'
cd /home/enrico/hana/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/enrico/hana /home/enrico/hana/test /home/enrico/hana/build /home/enrico/hana/build/test /home/enrico/hana/build/test/CMakeFiles/test.string.zero.dir/DependInfo.cmake --color=
Dependencies file "test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o.d" is newer than depends file "/home/enrico/hana/build/test/CMakeFiles/test.string.zero.dir/compiler_depend.internal".
Consolidate compiler generated dependencies of target test.string.zero
make[3]: Leaving directory '/home/enrico/hana/build'
make  -f test/CMakeFiles/test.string.zero.dir/build.make test/CMakeFiles/test.string.zero.dir/build
make[3]: Entering directory '/home/enrico/hana/build'
Building CXX object test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o
cd /home/enrico/hana/build/test && /usr/bin/c++ -DBOOST_HANA_CONFIG_ENABLE_STRING_UDL -I/home/enrico/hana/test/_include -I/home/enrico/hana/include -fdiagnostics-color -ftemplate-backtrace-limit=0 -pedantic -Wall -Werror -Wextra -Wno-self-assign-overloaded -Wno-unused-local-typedefs -Wwrite-strings -MD -MT test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o -MF CMakeFiles/test.string.zero.dir/string/zero.cpp.o.d -o CMakeFiles/test.string.zero.dir/string/zero.cpp.o -c /home/enrico/hana/test/string/zero.cpp
In file included from /home/enrico/hana/include/boost/hana/string.hpp:13,
                 from /home/enrico/hana/test/string/zero.cpp:7:
/home/enrico/hana/include/boost/hana/fwd/string.hpp:268:24: error: ISO C++ did not adopt string literal operator templates taking an argument pack of characters [-Werror=pedantic]
  268 |         constexpr auto operator"" _s();
      |                        ^~~~~~~~
In file included from /home/enrico/hana/test/string/zero.cpp:7:
/home/enrico/hana/include/boost/hana/string.hpp:117:24: error: ISO C++ did not adopt string literal operator templates taking an argument pack of characters [-Werror=pedantic]
  117 |         constexpr auto operator"" _s() {
      |                        ^~~~~~~~
cc1plus: note: unrecognized command-line option ‘-Wno-self-assign-overloaded’ may have been intended to silence earlier diagnostics
cc1plus: all warnings being treated as errors
make[3]: *** [test/CMakeFiles/test.string.zero.dir/build.make:76: test/CMakeFiles/test.string.zero.dir/string/zero.cpp.o] Error 1
make[3]: Leaving directory '/home/enrico/hana/build'
make[2]: *** [CMakeFiles/Makefile2:12963: test/CMakeFiles/test.string.zero.dir/all] Error 2
make[2]: Leaving directory '/home/enrico/hana/build'
make[1]: *** [CMakeFiles/Makefile2:12970: test/CMakeFiles/test.string.zero.dir/rule] Error 2
make[1]: Leaving directory '/home/enrico/hana/build'
make: *** [Makefile:5834: test.string.zero] Error 2

[ricejasonf]

I guess GCC just changed their policy, and we are not up to date with that.

For the tests there is only test.string.udl that actually requires BOOST_HANA_CONFIG_ENABLE_STRING_UDL.

We should disable it by default and add it only for the pertinent test/examples. Looking at tests/CMakeLists.txt there is an example of handling a set of tests differently. github_75 is added to the list of excluded tests and then has special rules applied to it. We should do something similar for test.string.udl, perhaps having the boost_hana_set_test_properties cmake function handle tests that require it such that -pedantic is not set only when necessary.

[Aster89]

And how do I go about it? Sorry, but I know very little about makefiles and build systems 😢