increment in base buildout causes unexpected results

[Dylan Jay]

If you have
base.cfp >
[buildout]
parts += blah

buildout.cfg >
parts += something

This will result in parts = blah which is unexpected and painful to debug.

The bug is in the function

def _update(d1, d2):
    for section in d2:
        if section in d1:
            d1[section] = _update_section(d1[section], d2[section])
        else:
            d1[section] = d2[section]
    return d1

when parsing base you'd end up with both "parts" and "parts+" in the section. Then in _update_section, one of the 'parts' will be lost.

[Dylan Jay (t-launchpad-dylanjay-com)]

sorry that should be

base.cfg
------------------------------
[buildout]
parts += blah

buildout.cfg
------------------------------
[buildout]
extends = base.cfg
parts += something