Comment 1 for bug 684120

I have a hint what may cause this.

It seems that buildout (not sure if always, or just in some cases, or just recently) tries to force its own PYTHONPATH to any python executable run from it, this even has an effect if - like bzr - we want to run a separately installed application that brings its own python and libs.

This is clearly a problem in the case of any application like bzr, that needs to import modules, which won't be present if buildout forces its path.

Could you please put a pdb breakpoint before the import statement that fails, and print out sys.path? Then, run bzr by hand and print out sys.path in that case?

If there is a difference than buildout's behaviour is the problem. In this case we could probably solve this problem by resetting PYTHONPATH before running bzr (and we don't have to raise an argument with the buildout developers about the issue)

-S _may_ also be a problem, as you mention.