fail in recursive extended sections (macros)

[Dylan Jay]

[buildout]
parts = part1 part2

[mypart]
recipe = blah

[part1]
<= mypart

[part2]
<= part1

This will fail with a "no recipe found for part2".

It looks like the reason is in in _do_extend_raw
Line 1060: to_do = data.pop('<', None)

Since the data extension is popped remove from part1 first, part2 will fail extend from just part1 and not mypart.
The work around is

[part2]
<= mypart
     part1

But you wouldn't expect to have to do that.