Huh?? sbuild fails and pbuilder succeeds in building a Fortran-containing Python package

[Julian Gilbey <jdg@debian.org>]

I wonder if anyone has an idea about this thorny problem.  I'm trying
to create a package and thought I'd got something wrong, but have
found the same behaviour happens with the "amp" package (version
0.6.1-1) and the "spherepack" package (version 3.3~a1-4), which
suggests to me that the problem lies outside of the package itself.
But I have very little idea how to track this bug down.


If I run sbuild:
  sbuild -s -A -d unstable spherepack_3.3~a1-4.dsc
then the build starts OK, but when it comes to compiling the C sources
(or maybe it's actually the Fortran sources - I don't know), I get the
following:

[...]
building 'spherepack' extension
compiling C sources
C compiler: x86_64-linux-gnu-gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O2 -Wall -g -ffile-prefix-map=/build/python3.9-euU3fN/python3.9-3.9.1=. -fstack-protector-strong -Wformat -Werror=format-security -g -fwrapv -O2 -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC

creating build/temp.linux-x86_64-3.9/build
creating build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9
creating build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src
creating build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/build
creating build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/build/src.linux-x86_64-3.9
creating build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src
compile options: '-Ibuild/src.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src -I/usr/lib/python3/dist-packages/numpy/core/include -I/usr/include/python3.9 -c'
error: [Errno 13] Permission denied

An identical "Permission denied" error happens with the "amp" package
as well, and also with the new package that I'm working on.

However, with pbuilder:
  pbuilder build spherepack_3.3~a1-4.dsc
I get a successful build, and the similar part of the output reads:

[...]
building 'spherepack' extension
compiling C sources
C compiler: x86_64-linux-gnu-gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O2 -Wall -g -ffile-prefix-map=/build/python3.9-euU3fN/python3.9-3.9.1=. -fstack-protector-strong -Wformat -Werror=format-security -g -fwrapv -O2 -g -O2 -ffile-prefix-map=/build/spherepack-3.3~a1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC

compile options: '-Ibuild/src.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src -I/usr/lib/python3/dist-packages/numpy/core/include -I/usr/include/python3.9 -c'
x86_64-linux-gnu-gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro -g -fwrapv -O2 -Wl,-z,relro -g -O2 -ffile-prefix-map=/build/spherepack-3.3~a1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src/spherepackmodule.o build/temp.linux-x86_64-3.9/build/src.linux-x86_64-3.9/build/src.linux-x86_64-3.9/Src/fortranobject.o -L/build/spherepack-3.3~a1/Src -lsphere -o build/lib.linux-x86_64-3.9/spherepack.cpython-39-x86_64-linux-gnu.so
running install_lib
[...]

They are so different, yet supposedly using essentially identical
build environments.  (They are also both using sid repositories.)


If you have any idea why I might be seeing this behaviour, and what I
might be able to do about it, that would be fantastic!

Thanks!

   Julian