Refine groups functionality

Every project is in group "default".  "-default" does not remove
it from this project.  All group names specified in the manifest
are positive names as opposed to a mix of negative and positive.

Specified groups are resolved in order.  If init is supplied with
--groups="group1,-group2", the following describes the project
selection when syncing:

  * all projects in "group1" will be added, and
  * all projects in "group2" will be removed.

Change-Id: I1df3dcdb64bbd4cd80d675f9b2d3becbf721f661

1 files changed, 8 insertions, 2 deletions

diff --git a/subcmds/init.py b/subcmds/init.py
index 6cf39d14..d1c497c1 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import os
+import re
 import shutil
 import sys
 
@@ -87,7 +88,7 @@ to update the working directory files.
                  dest='depth',
                  help='create a shallow clone with given depth; see git clone')
     g.add_option('-g', '--groups',
-                 dest='groups', default="",
+                 dest='groups', default='default',
                  help='restrict manifest projects to ones with a specified group',
                  metavar='GROUP')
 
@@ -139,7 +140,12 @@ to update the working directory files.
       r.ResetFetch()
       r.Save()
 
-    m.config.SetString('manifest.groups', opt.groups)
+    groups = re.split('[,\s]+', opt.groups)
+    groups = [x for x in groups if x]
+    groupstr = ','.join(groups)
+    if groupstr == 'default':
+      groupstr = None
+    m.config.SetString('manifest.groups', groupstr)
 
     if opt.reference:
       m.config.SetString('repo.reference', opt.reference)