Bug#377964: [Build-common-hackers] Bug#377964: cdbs should use the unversioned interpreter for the default python version

[Matthias Klose]

Peter Eisentraut writes:
> Matthias Klose wrote:
> > the interpreter is used by installation scripts to set the
> > interpreter name in scripts, leading to hash lines
> > /usr/bin/python2.3, which dh_python then turns into a python2.3
> > dependency. Please call the unversioned interpreter for the default
> > python version.
> 
> I have implemented a fix for this -- see attached patch -- but it breaks 
> the python-numpy build, which you nominated as example, so I'm unsure 
> what to do.

I'll have a look. In which ways does it break?

> On further consideration, I think packages that rely on this behavior 
> either way are in error.  The policy says that if programs can run with 
> any version, they must use /usr/bin/python as interpreter, so this must 
> be a fixed value, no matter how the build script is called or whether 
> the version being used for building is the default one at build time.  
> If, on the other hand, a program really needs a specific version 
> because of the way it is written, that version should be hard-wired 
> into the program, no matter what version you use to run the build 
> script.

I agree that the version should be hard-wired, if a non-default python
version is used/needed. I just want to have the maintainer to have to
do nothing else for common cases, i.e. if the package is built for the
'current' version, no upload should be required if the default version
changes. files which are installed into the common
pycentral/python-support area should always use the unversioned
interpreter, but maybe these tools should enforce that themself.

  Matthias