Build error of met@11.0.2 with clang@13.1.6 on macOS

[climbfuji]

Trying to build met@11.0.2 with clang@13.1.6 on my macOS in spack-stack. We are currently building met@10.1.1 and metplus@4.1.1 in spack-stack on many different platforms, including my macOS, using these recipes:

https://github.com/NOAA-EMC/spack/tree/4bc1363413325c2ee2f288eecce1134f8c89af58/var/spack/repos/builtin/packages/met/
https://github.com/NOAA-EMC/spack/tree/4bc1363413325c2ee2f288eecce1134f8c89af58/var/spack/repos/builtin/packages/metplus/

The error I am getting is:

Making all in vx_seeps
/Users/heinzell/work/spack-stack/spack-stack-1.3.1/spack/lib/spack/env/clang/clang++ -DHAVE_CONFIG_H -I. -I../../..  -I../../../src/basic/vx_cal -I../../../src/basic/vx_config -I../../../src/basic/vx_log -I../../../src/basic/vx_math -I../../../src/basic/vx_util -I../../../src/basic/vx_util_math -I../../../src/libcode/vx_afm -I../../../src/libcode/vx_analysis_util -I../../../src/libcode/vx_color -I../../../src/libcode/vx_data2d -I../../../src/libcode/vx_data2d_factory -I../../../src/libcode/vx_data2d_grib -I../../../src/libcode/vx_data2d_grib2 -I../../../src/libcode/vx_data2d_nccf -I../../../src/libcode/vx_data2d_nc_met -I../../../src/libcode/vx_data2d_nc_pinterp -I../../../src/libcode/vx_data2d_python -I../../../src/libcode/vx_python3_utils -I../../../src/libcode/vx_geodesy -I../../../src/libcode/vx_gis -I../../../src/libcode/vx_gnomon -I../../../src/libcode/vx_grid -I../../../src/libcode/vx_gsl_prob -I../../../src/libcode/vx_nav -I../../../src/libcode/vx_nc_obs -I../../../src/libcode/vx_nc_util -I../../../src/libcode/vx_pb_util -I../../../src/libcode/vx_plot_util -I../../../src/libcode/vx_pointdata_python -I../../../src/libcode/vx_ps -I../../../src/libcode/vx_pxm -I../../../src/libcode/vx_render -I../../../src/libcode/vx_regrid -I../../../src/libcode/vx_shapedata -I../../../src/libcode/vx_solar -I../../../src/libcode/vx_statistics -I../../../src/libcode/vx_stat_out -I../../../src/libcode/vx_bool_calc -I../../../src/libcode/vx_summary -I../../../src/libcode/vx_time_series -I../../../src/libcode/vx_series_data -I../../../src/libcode/vx_seeps -I../../../src/libcode/vx_tc_util -I/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/netcdf-c-4.9.2-dj7rkty/include -I/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/netcdf-cxx4-4.3.1-qbvrrsj/include -D__64BIT__  -I/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/g2c-1.6.4-py3e6gl/include -I../../basic/vx_log -I../../basic/vx_util -I/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/python-3.10.8-kyolkyg/include/python3.10 -I/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/gsl-2.7.1-pmqafof/include -DBLOCK4 -DWITH_GRIB2 -DWITH_PYTHON -DMET_BASE="\"/Users/heinzell/work/spack-stack/spack-stack-1.3.1/envs/unified-env/install/apple-clang/13.1.6/met-11.0.2-wqygltz/share/met\""   -MT libvx_seeps_a-seeps.o -MD -MP -MF .deps/libvx_seeps_a-seeps.Tpo -c -o libvx_seeps_a-seeps.o `test -f 'seeps.cc' || echo './'`seeps.cc
seeps.cc:6:17: warning: using directive refers to implicitly-defined namespace 'std'
using namespace std;
                ^
seeps.cc:340:20: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
       ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
seeps.cc:340:20: note: place parentheses around the assignment to silence this warning
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
                   ^
       (                                                )
seeps.cc:340:20: note: use '==' to turn this assignment into an equality comparison
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
                   ^
                   ==
seeps.cc:651:60: error: expected '('
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                           ^
seeps.cc:651:66: error: expected ';' after expression
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                                 ^
                                                                 ;
seeps.cc:651:61: warning: expression result unused [-Wunused-value]
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                            ^~~~~
seeps.cc:651:67: error: expected unqualified-id
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                                  ^
seeps.cc:787:20: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
       ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
seeps.cc:787:20: note: place parentheses around the assignment to silence this warning
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
                   ^
       (                                                )
seeps.cc:787:20: note: use '==' to turn this assignment into an equality comparison
   if (seeps_ready = file_exists(seeps_filename.c_str())) {
                   ^
                   ==
4 warnings and 3 errors generated.
make[4]: *** [libvx_seeps_a-seeps.o] Error 1
make[3]: *** [all-recursive] Error 1
make[2]: *** [all-recursive] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

I'd like to be able to build the latest met version on all systems we currently support, but if that's not possible in the short term then my question is whether metplus@5.x.y works with met@10.1.1?

[JohnHalleyGotway]

Hi Dom,

While I routinely compile/run MET on my Mac, I do so using GNU compilers installed via MacPorts or HomeBrew. As you've found, we have not ported MET over to the Clang compiler on Mac. It would be very easy to work around those specific compiler errors you list...

Replacing...

if (seeps_ready = file_exists(seeps_filename.c_str())) {

With...

seeps_ready = file_exists(seeps_filename.c_str());
if (seeps_ready) {

But the trouble is that once you start pulling on that thread, you don't know how long or difficult it'll end up being.

@jprestop and @TaraJensen, any input, perspective, or advice on porting MET over to the Clang compiler, which is very widely used on Mac?

[climbfuji]

Hi Dom,

While I routinely compile/run MET on my Mac, I do so using GNU compilers installed via MacPorts or HomeBrew. As you've found, we have not ported MET over to the Clang compiler on Mac. It would be very easy to work around those specific compiler errors you list...

Replacing...

if (seeps_ready = file_exists(seeps_filename.c_str())) {

With...

seeps_ready = file_exists(seeps_filename.c_str());
if (seeps_ready) {

But the trouble is that once you start pulling on that thread, you don't know how long or difficult it'll end up being.

@jprestop and @TaraJensen, any input, perspective, or advice on porting MET over to the Clang compiler, which is very widely used on Mac?

@JohnHalleyGotway These four are just warnings, the three real errors are here:

seeps.cc:651:60: error: expected '('
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                           ^
seeps.cc:651:66: error: expected ';' after expression
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                                 ^
                                                                 ;
seeps.cc:651:61: warning: expression result unused [-Wunused-value]
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}
                                                            ^~~~~
seeps.cc:651:67: error: expected unqualified-id
SeepsClimoGrid::SeepsClimoGrid(int month, int hour) : month{month}, hour{hour}

Regarding gnu vs clang. If you talk to the spack developers (and to us spack-stack developers), you'll get the answer that gcc/g++ are not the recommended compilers and in fact don't build a large fraction of the entire software stack (especially all the Python utilities). You need clang for that. And, in fact, we are building met@10.1.1 and metplus@4.1.1 without problems with clang (after I provided back one bug fix a year ago or so).

[JohnHalleyGotway]

@climbfuji thanks for the reminder of the fix you provided and your success with 10.1.1. With that in mind, the next steps seem pretty clear to me.

1. We should fix the main_v11.0 and develop branches in MET to get it compiling with Clang again.
2. Create an 11.0.3 bugfix release to provide that bugfix.
3. Setup a GitHub action to test the compilation of MET via Clang for each Pull Request to ensure that it remains fixed.

Does that match what you're thinking as well?

[climbfuji]

That sounds great! Willing to help if I can. Thanks!

[climbfuji]

I am closing this discussion, given that the code was fixed recently and an issue was created to add clang to the CI tests. Thanks for everyone who worked on this.