startup script uses PYTHONPATH instead of sys.path

[Georges Racinet]

The openerp startup script created by the recipe sets the path through the PYTHONPATH environment variable.

This is less robust than the sys.path hacking done by other recipes : IIRC PYTHONPATH is interpreted in site.py, and some linux distros (I've seen it on Debian Etch, don't know if it's still current) may ignore it or have the global site-packages (dist-packages for Debian) take precedence over it, which breaks the reproducibility of the buildout.

Also, creating python startups open the road to more flexibility. An example : a startup scripts for tests may want to load a cheatable datetime implementation.

[Georges Racinet (gracinet)]

update: I made the PYTHONPATH test on Debian Squeeze, and PYTHONPATH now has precedence.
That doesn't change the fact that sys.path setting is a better warranty and the above mentionned flexibility

[Georges Racinet (gracinet)]

After a bit of investigation, I conclude that the best is to use a custom interpreter to launch openerp.
Reasons:

 - the startup script of openerp 6.1 is not modular enough yet (the if __name__ part does not relay to a single callable). Therefore, simply doing as for console_scripts would not work right away (or would lead us to unwanted code duplication) ;
- we want to support from 6.0 up anyway, and the custom interpreter can bring the kind of uniformity we need.

This can be done by giving the 'interpreter' option a default value.

[Georges Racinet (gracinet)]

pushed experiment following the above lines in this issue's related branch

[Georges Racinet (gracinet)]

For OpenERP >= 6.1, the work done in this branch is now deprecated by the better solution done for #1019886

[Georges Racinet (gracinet)]

Now obsolete in all supported cases, unlinked the experimental branch