Re: [gpsd-dev] python2 and absolute paths

[Eric S. Raymond]

Greg Troxel <address@hidden>:
> But I'm not talking about API compat.  I'm talking about ABI
> compatibility of what's been built.  gpsd bakes in paths to the python
> version, in library linking, and where files get put.  So it basically
> can't work after changing out the interpreter from 2.6 to 2.7 without a
> rebuild.

Two questions:

(1) Where does it do this?  I see no mention of the Python version in
SConstruct;  I just reread it to check.

(2) Supposing it did do this, how would that be relevant to the desirability
of performing hashbang surgery on scripts, which is what you started out
arguing for?

> Your expectations are reasonable, but that's not how python has been.
> If it were, then packaging systems would not have had python 2.4 through
> 2.7 in parallel.

I think you are looking at the wrong evidence.  It's reasonable to carry
all those extra intermediate versions in repositories, because it costs
very little to do so.  On the other hand, space on distribution CD-ROMs
is at more of a premium and here's what I see:

address@hidden:~/software/ntp-rescue/ntpsec$ ls /usr/bin/python*
/usr/bin/python            /usr/bin/python3        /usr/bin/python_count
/usr/bin/python2           /usr/bin/python3.4      /usr/bin/pythontex
/usr/bin/python2.7         /usr/bin/python3.4m     /usr/bin/pythontex3
/usr/bin/python2.7-config  /usr/bin/python3m
/usr/bin/python2-config    /usr/bin/python-config

That pretty much tells the tale right there.

> Even with perl, updating pkgsrc to 5.22 resulted in a bunch of
> failures.   They were all nits that were easy to fix, the same kind of
> thing that happens with C code with newer compiler versions.    The
> point is that it's easier to fix them all than to maintain two versions
> in parallel, unlike what happened with python.

Sounds like the Perl guys fell down on the job a bit. So far as I am aware
the Python guys have not.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>

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