Special handling for manifest group "default"

Change Details:
* Make "default" a special manifest group that matches any project that
  does not have the special project group "notdefault"
* Use "default" instead of "all,-notdefault" when user does not specify
  manifest group
* Expand -g option help to include example usage of manifest groups

Change Benefits:
* Allow a more intuitive and expressive manifest groups specification:
  * "default" instead of "all,-notdefault"
  * "default,foo" instead of "all,-notdefault,foo"
  * "default,-foo" instead of "all,-notdefault,-foo"
  * "foo,-default" which has no equivalent
* Default manifest groups behavior can be restored by the command
  'repo init -g default'. This is significantly more intuitive than the
  current equivalent command 'repo init -g all,-notdefault'.

Change-Id: I6d0673791d64a650110a917c248bcebb23b279d3

1 files changed, 6 insertions, 1 deletions

diff --git a/project.py b/project.py
index 22e4a5d6..901a2831 100644
--- a/project.py
+++ b/project.py
@@ -672,9 +672,14 @@ class Project(object):
        project_groups: "all,group1,group2"
        manifest_groups: "-group1,group2"
        the project will be matched.
+
+       The special manifest group "default" will match any project that
+       does not have the special project group "notdefault"
     """
-    expanded_manifest_groups = manifest_groups or ['all', '-notdefault']
+    expanded_manifest_groups = manifest_groups or ['default']
     expanded_project_groups = ['all'] + (self.groups or [])
+    if not 'notdefault' in expanded_project_groups:
+      expanded_project_groups += ['default']
 
     matched = False
     for group in expanded_manifest_groups: