Re: [gpsd-dev] Python Shebang Lines

[Gary E. Miller]

Yo Fred!

On Tue, 27 Dec 2016 15:02:07 -0800 (PST)
Fred Wright <address@hidden> wrote:

> On Tue, 27 Dec 2016, Gary E. Miller wrote:
> > On Tue, 27 Dec 2016 14:14:38 -0800 (PST)
> > Fred Wright <address@hidden> wrote:
> >  
> > > At one point, Eric said that he thought that it was rare for
> > > people to have multiple Python versions installed, but I think
> > > that's likely to become a lot less true with the advent of Python
> > > 3.  
> >
> > Gentoo by default installs Python 2 and Python 2.  The eselect
> > commmand the configures which one /usr/bin/python goes to.  
> 
> Presumably you mean Python2 and Python 3.

Sorry, yes.

> Yes, and changing that selection after you've installed any required
> third-party add-ons will break anything that depends on those add-ons
> and doesn't have a shebang line tying it to the proper version.

Actually, on Gentoo, that would be a negatory.

> > OTOH, gpsd should not care at all which is the running Python.
> > ntpsec has no issuses with that.  
> 
> I think I explained in quite a bit of detail why multi-version
> compatibility is not the same thing as not caring which version is
> *currently* in use.

Yes, and I did not bother tpo answert point by point since IMHO you
overcomplicated it.  As I said, ntpsec has zero issues with mulit-versions
of python, no matter how you want to permute the issue.

> > It runs on everything we have tried it on.  gpsd should do the
> > same.  
> 
> Unless it uses nothing but standard Python libraries, I think you'll
> find that "runs on everything" just means that you haven't tried
> enough cases. :-) I've been burned two different ways by this issue.

Well, ntpsec gets built on about 2 dozen different distros, including
OS X.  So the corner cases are hidden deep.

> In any case, what I've currently implemented doesn't *require*
> non-generic shhebang lines; it simply provides a mechanism to have
> them without requiring the user or packaging system to know what
> needs to be patched.

Better yet, make it so nothing needs to be patched, ever.

> BTW, I looked at what SCons itself does on a variety of platforms, and
> found that Linux is the *only* platform where it uses generic shebang
> lines, and even that will have to change on any distro where the
> default Python is Python 3.

I have not found that scons needs any change to run on Python 3.

RGDS                                              Veritas liberabit vos 
GARY                                                   Quid est veritas?
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden  Tel:+1 541 382 8588

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