parse_layout_conf: comment on masters fallback

diff --git a/pym/portage/repository/config.py b/pym/portage/repository/config.py
index d64ad4f2fbd80abe3df1c7bcb11b5bfd1e02a635..19c1aeb86a5a0fe1fa90446c9b212eb8cd55a931 100644 (file)
--- a/pym/portage/repository/config.py
+++ b/pym/portage/repository/config.py
@@ -622,8 +622,11 @@ def parse_layout_conf(repo_location, repo_name=None):
 
        data = {}
 
-       # allow None to slip through; later code spots that as an indication
-       # that an explicit nulling of the overlaying is desired.
+       # None indicates abscence of a masters setting, which later code uses
+       # to trigger a backward compatibility fallback that sets an implicit
+       # master. In order to avoid this fallback behavior, layout.conf can
+       # explicitly set masters to an empty value, which will result in an
+       # empty tuple here instead of None.
        masters = layout_data.get('masters')
        if masters is not None:
                masters = tuple(masters.split())