[Python-modules-team] Bug#957780: scipy: ftbfs with GCC-10

[Matthias Klose]

Package: src:scipy
Version: 1.3.3-3
Severity: normal
Tags: sid bullseye
User: debian-gcc at lists.debian.org
Usertags: ftbfs-gcc-10

Please keep this issue open in the bug tracker for the package it
was filed for.  If a fix in another package is required, please
file a bug for the other package (or clone), and add a block in this
package. Please keep the issue open until the package can be built in
a follow-up test rebuild.

The package fails to build in a test rebuild on at least amd64 with
gcc-10/g++-10, but succeeds to build with gcc-9/g++-9. The
severity of this report will be raised before the bullseye release,
so nothing has to be done for the buster release.

The full build log can be found at:
http://people.debian.org/~doko/logs/gcc10-20200225/scipy_1.3.3-3_unstable_gcc10.log
The last lines of the build log are at the end of this report.

To build with GCC 10, either set CC=gcc-10 CXX=g++-10 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t=experimental install g++ 

Common build failures are new warnings resulting in build failures with
-Werror turned on, or new/dropped symbols in Debian symbols files.
For other C/C++ related build failures see the porting guide at
http://gcc.gnu.org/gcc-10/porting_to.html

[...]
stat.h:8:35:

Warning: Unused variable ‘t4’ declared at (1) [-Wunused-variable]
stat.h:8:39:

Warning: Unused variable ‘t5’ declared at (1) [-Wunused-variable]
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/zmout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/second_NONE.f
scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/second_NONE.f:17:27:

   17 |       REAL               T1
      |                           1
Warning: Unused variable ‘t1’ declared at (1) [-Wunused-variable]
scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/second_NONE.f:20:36:

   20 |       REAL               TARRAY( 2 )
      |                                    1
Warning: Unused variable ‘tarray’ declared at (1) [-Wunused-variable]
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/smout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/cvout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/ssortr.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/sstatn.f
stat.h:8:19:

Warning: Unused variable ‘t0’ declared at (1) [-Wunused-variable]
stat.h:8:23:

Warning: Unused variable ‘t1’ declared at (1) [-Wunused-variable]
stat.h:8:27:

Warning: Unused variable ‘t2’ declared at (1) [-Wunused-variable]
stat.h:8:31:

Warning: Unused variable ‘t3’ declared at (1) [-Wunused-variable]
stat.h:8:35:

Warning: Unused variable ‘t4’ declared at (1) [-Wunused-variable]
stat.h:8:39:

Warning: Unused variable ‘t5’ declared at (1) [-Wunused-variable]
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/dmout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/zvout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/svout.f
gfortran:f77: /<<PKGBUILDDIR>>/scipy/_build_utils/src/wrap_dummy_g77_abi.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/dvout.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/icnteq.f
gfortran:f77: scipy/sparse/linalg/eigen/arpack/ARPACK/UTIL/icopy.f
Running from scipy source directory.
/usr/lib/python3/dist-packages/numpy/distutils/system_info.py:690: UserWarning: 
    Optimized (vendor) Blas libraries are not found.
    Falls back to netlib Blas library which has worse performance.
    A better performance should be easily gained by switching
    Blas library.
  self.calc_info()
/usr/lib/python3/dist-packages/numpy/distutils/system_info.py:782: UserWarning: Specified path /usr/local/include/python3.8 is invalid.
  return self.get_paths(self.section, key)
/usr/lib/python3/dist-packages/numpy/distutils/system_info.py:782: UserWarning: Specified path /usr/include/suitesparse/python3.8 is invalid.
  return self.get_paths(self.section, key)
/usr/lib/python3/dist-packages/numpy/distutils/fcompiler/__init__.py:517: UserWarning: FFLAGS is used as is, not appended to flags already defined by numpy.distutils! Use NPY_DISTUTILS_APPEND_FLAGS=1 to obtain appending behavior instead (this behavior will become default in a future release).
  fflags = self.flag_vars.flags + dflags + oflags + aflags
/usr/lib/python3/dist-packages/numpy/distutils/fcompiler/__init__.py:517: UserWarning: FFLAGS is used as is, not appended to flags already defined by numpy.distutils! Use NPY_DISTUTILS_APPEND_FLAGS=1 to obtain appending behavior instead (this behavior will become default in a future release).
  fflags = self.flag_vars.flags + dflags + oflags + aflags
/usr/lib/python3/dist-packages/numpy/distutils/fcompiler/__init__.py:517: UserWarning: FFLAGS is used as is, not appended to flags already defined by numpy.distutils! Use NPY_DISTUTILS_APPEND_FLAGS=1 to obtain appending behavior instead (this behavior will become default in a future release).
  fflags = self.flag_vars.flags + dflags + oflags + aflags
error: Command "/usr/bin/gfortran -Wall -g -ffixed-form -fno-second-underscore -fPIC -O3 -funroll-loops -Iscipy/sparse/linalg/eigen/arpack/ARPACK/SRC -I/usr/lib/python3/dist-packages/numpy/core/include -c -c scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/dsaitr.f -o build/temp.linux-amd64-3.8/scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/dsaitr.o" failed with exit status 1
E: pybuild pybuild:341: configure: plugin distutils failed with: exit code=1: python3.8 setup.py config config_fc --noarch build
make[1]: *** [debian/rules:38: build-python3.8] Error 13
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:22: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2