[Python-modules-team] Bug#976983: sip-build fails to run on some machines when python3-sip is installed

[Julian Gilbey]

Package: python3-sipbuild
Version: 5.5.0+dfsg-1+b1
Severity: important
X-Debbugs-Cc: python3-sip at packages.debian.org

I have both python3-sip (4.19.24+dfsg-1+b2) and python3-sipbuild
(5.5.0+dfsg-1+b1) installed on two different machines running
testing.  On one of the machines, I get the following output (with
sip5-tools installed):

$ sip-build --version
5.5.0

while on the other I get an error message:

$ sip-build --version
Traceback (most recent call last):
  File "/usr/bin/sip-build", line 33, in <module>
    sys.exit(load_entry_point('sip==5.5.0', 'console_scripts', 'sip-build')())
  File "/usr/bin/sip-build", line 25, in importlib_load_entry_point
    return next(matches).load()
StopIteration

I've done a bit of digging, and it turns out that the following gives
different results on the two machines; on one machine I get:

$ python3
Python 3.9.1rc1 (default, Nov 27 2020, 19:38:39) 
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from importlib.metadata import distribution
>>> distribution('sip')._path
PosixPath('/usr/lib/python3/dist-packages/sip-5.5.0.egg-info')
>>> 

whereas on the other, I get the output
PosixPath('/usr/lib/python3/dist-packages/sip-4.19.24.dist-info')

I'm guessing that the order in which the info files are found is
filesystem-dependent or something.  The result, though, is that
sip-build and all of the other binaries in sip5-tools potentially fail
if python3-sip is installed.

One solution might be to install the egg-info file as sipbuild-5.5.0;
another might be to conflict with python3-sip.

Best wishes,

   Julian

-- System Information:
Debian Release: bullseye/sid
  APT prefers stretch
  APT policy: (500, 'stretch'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.9.0-4-amd64 (SMP w/4 CPU threads)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_GB.UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages python3-sipbuild depends on:
ii  libc6              2.31-5
ii  python3            3.9.0-4
ii  python3-packaging  20.4-1
ii  python3-toml       0.10.1-1

python3-sipbuild recommends no packages.

python3-sipbuild suggests no packages.

-- no debconf information