Mixed source Fortran C project fails to build with 0.57

[awvwgk]

Describe the bug

Meson 0.57 fails to build mixed source Fortran/C projects.

To Reproduce

Minimal project producing the error: mwe.tar.gz

> meson setup _build
The Meson build system
Version: 0.57.0
Source dir: /home/awvwgk/projects/src/git/bugs/meson-0.57
Build dir: /home/awvwgk/projects/src/git/bugs/meson-0.57/_build
Build type: native build
Project name: mwe
Project version: undefined
Fortran compiler for the host machine: gfortran (gcc 10.2.0 "GNU Fortran (GCC) 10.2.0")
Fortran linker for the host machine: gfortran ld.bfd 2.36
C compiler for the host machine: cc (gcc 10.2.0 "cc (GCC) 10.2.0")
C linker for the host machine: cc ld.bfd 2.36
Host machine cpu family: x86_64
Host machine cpu: x86_64
Build targets in project: 1

Found ninja-1.10.2 at /home/awvwgk/miniforge3/envs/mesonbuild/bin/ninja
> ninja -C _build
ninja: Entering directory `_build'
[1/4] Module scanner.
ninja: build stopped: 'mwe.p/file.c.o' not mentioned in its dyndep file 'mwe.p/depscan.dd'.

Meson log file: meson-log.txt

Let me know if you need any additional information.

Expected behavior

Correctly build mixed Fortran/C project.

system parameters

• Is this a cross build or just a plain native build (for the same computer)?
  native build
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.)

> conda info
conda info

     active environment : mesonbuild
    active env location : /home/awvwgk/miniforge3/envs/mesonbuild
            shell level : 2
       user config file : /home/awvwgk/.condarc
 populated config files : /home/awvwgk/miniforge3/.condarc
          conda version : 4.9.2
    conda-build version : not installed
         python version : 3.7.8.final.0
       virtual packages : __glibc=2.33=0
                          __unix=0=0
                          __archspec=1=x86_64
       base environment : /home/awvwgk/miniforge3  (writable)
           channel URLs : https://conda.anaconda.org/conda-forge/linux-64
                          https://conda.anaconda.org/conda-forge/noarch
          package cache : /home/awvwgk/miniforge3/pkgs
                          /home/awvwgk/.conda/pkgs
       envs directories : /home/awvwgk/miniforge3/envs
                          /home/awvwgk/.conda/envs
               platform : linux-64
             user-agent : conda/4.9.2 requests/2.24.0 CPython/3.7.8 Linux/5.9.16-1-MANJARO manjaro/20.2.1 glibc/2.33
                UID:GID : 1000:1000
             netrc file : None
           offline mode : False
> uname -a
Linux saw8203 5.9.16-1-MANJARO #1 SMP PREEMPT Mon Dec 21 22:00:46 UTC 2020 x86_64 GNU/Linux

• what Python version are you using e.g. 3.8.0
• what meson --version
• what ninja --version if it's a Ninja build

> conda list
# packages in environment at /home/awvwgk/miniforge3/envs/mesonbuild:
#
# Name                    Version                   Build  Channel
_libgcc_mutex             0.1                 conda_forge    conda-forge
_openmp_mutex             4.5                       1_gnu    conda-forge
ca-certificates           2020.12.5            ha878542_0    conda-forge
certifi                   2020.12.5        py37h89c1867_1    conda-forge
ld_impl_linux-64          2.35.1               hea4e1c9_2    conda-forge
libffi                    3.2.1             he1b5a44_1007    conda-forge
libgcc-ng                 9.3.0               h2828fa1_18    conda-forge
libgomp                   9.3.0               h2828fa1_18    conda-forge
libstdcxx-ng              9.3.0               h6de172a_18    conda-forge
meson                     0.57.0             pyhd8ed1ab_0    conda-forge
ncurses                   6.2                  h58526e2_4    conda-forge
ninja                     1.10.2               h4bd325d_0    conda-forge
openssl                   1.1.1j               h7f98852_0    conda-forge
pip                       21.0.1             pyhd8ed1ab_0    conda-forge
python                    3.7.8           h6f2ec95_0_cpython    conda-forge
python_abi                3.7                     1_cp37m    conda-forge
readline                  8.0                  he28a2e2_2    conda-forge
setuptools                49.6.0           py37h89c1867_3    conda-forge
sqlite                    3.34.0               h74cdb3f_0    conda-forge
tk                        8.6.10               hed695b0_1    conda-forge
wheel                     0.36.2             pyhd3deb0d_0    conda-forge
xz                        5.2.5                h516909a_1    conda-forge
zlib                      1.2.11            h516909a_1010    conda-forge
> python --version
Python 3.7.8
> meson --version
0.57.0
> ninja --version
1.10.2

[jpakkane]

Can you test if the linked MR fixes it for you? Thanks.

[awvwgk]

Thanks, fixes the example above. I'm still seeing a failure in the original project (module dependencies are built in wrong order), but this might be unrelated. I'll try to isolate it and report back.

[awvwgk]

I get with e2dabe1 into situation where source code is compiled before the dependency scan is done. Trying to build https://github.com/grimme-lab/xtb with the build files generated by the fixed version I get the following compilation order:

> ninja -C _build_fix -n -j 1 | cat
ninja: Entering directory `_build_fix'
[1/332] Compiling Fortran object lib_xtb.a.p/src_disp_dftd4.F90.o
[2/332] Compiling Fortran object lib_xtb.a.p/src_main_property.F90.o
[3/332] Compiling Fortran object lib_xtb.a.p/src_mctc_blas_level1.F90.o
[4/332] Compiling Fortran object lib_xtb.a.p/src_mctc_blas_level2.F90.o
[5/332] Compiling Fortran object lib_xtb.a.p/src_mctc_blas_level3.F90.o
[6/332] Compiling Fortran object lib_xtb.a.p/src_mctc_lapack_eigensolve.F90.o
[7/332] Compiling Fortran object lib_xtb.a.p/src_mctc_systools.F90.o
[8/332] Compiling Fortran object lib_xtb.a.p/src_mctc_mctc_global.F90.o
[9/332] Compiling Fortran object lib_xtb.a.p/src_mctc_mctc_init.F90.o
[10/332] Compiling C object lib_xtb.a.p/src_mctc_signal.c.o
[11/332] Compiling Fortran object lib_xtb.a.p/src_type_reader.F90.o
[12/332] Compiling Fortran object lib_xtb.a.p/src_solv_input.F90.o
[13/332] Compiling Fortran object lib_xtb.a.p/src_xtb_repulsion.F90.o
[14/332] Compiling Fortran object lib_xtb.a.p/src_filetools.F90.o
[15/332] Compiling Fortran object lib_xtb.a.p/src_hessian.F90.o
[16/332] Compiling Fortran object lib_xtb.a.p/src_scf_module.F90.o
[17/332] Compiling C object lib_xtb.a.p/symmetry_symmetry_i.c.o
[18/332] Module scanner.

All Fortran objects seem to be compiled without any knowledge of module dependencies before step 18 and will therefore fail in a normal build. I'll try to create a reduced example to reproduce this behaviour.