Walking children commits?

[Mike Hommey <mh@glandium.org>]

Hi,

I am trying to get all the children commits of a set of commits. To do
that, I'm using this:

  git rev-list --topo-order --ancestry-path --boundary <all heads> ^A ^B ...

where A, B, and following are those commits I want the children of. From
the gitrevisions documentation, it seems that should get me what I want,
but if I build a dag manually (from the output of rev-list --parents)
and get all the children of those commits, I get more results than what
the command above returns (and that command also gives false positives).

Am I doing something wrong, or am I hitting a bug in --ancestry-path
walking? In the latter case, I'll try to find a reduced test case,
because currently, this involves a 260k commit, 1.5GB repository with
close to 2k heads and a set of 153 commits to find the children of.

Cheers,

Mike