buildout/buildout — pull request #22 by benoitbryon (2012-10-04 08:57:45+00:00)
Title: Issue 1060236: Multi extends which set the same option, and += behaviour

This pull-request is related to https://bugs.launchpad.net/zc.buildout/+bug/1060236

This is an implementation of the proposal described as first example of the ticket above:

* when using multiple inheritance...
* bases are merged with each other
* distinct sections and options are preserved as is
* duplicate sections and options are combined

```
.. code-block:: cfg
:filename: buildout.cfg

[buildout]
extends = base1.cfg base2.cfg
parts += foo

.. code-block:: cfg
:filename: base1.cfg

[buildout]
parts = base1

.. code-block:: cfg
:filename: base2.cfg

[buildout]
parts = base2
```

We get ``parts = base1 base2 foo`` (in fact: "base1\nbase2\nfoo").

If the feature is accepted, I'm ok to add more documentation if you like.