init: --dissociate option to copy objects borrowed with --reference

"repo init --reference" has two purposes: to decrease bandwidth used
at clone time, and to decrease disk usage afterward, by using the
reference repositories as an alternate store of objects even after
the clone. The downside is that it makes the borrowing repositories
dependent on the reference repositories, so it is easy to end up
with missing objects by mistake after a cleanup operation like "git
gc".

To prevent that, v2.3.0-rc0~30^2 (clone: --dissociate option to mark
that reference is only temporary, 2014-10-14), "git clone" gained a
--dissociate option that makes --reference reuse objects from the
reference repository at clone time but copy them over instead of
using the reference as an alternate. This is more straightforward to
use than plain --reference, at the cost of higher disk usage.

Introduce a --dissociate to "repo init" that brings the same benefits
to repo. The option is simply passed on to "git clone".

Change-Id: Ib50a549eb71e0a2b3e234aea57537923962a80d4

1 files changed, 10 insertions, 0 deletions

diff --git a/project.py b/project.py
index d551351b..a7001b01 100755
--- a/project.py
+++ b/project.py
@@ -1310,6 +1310,16 @@ class Project(object):
                               submodules=submodules)):
       return False
 
+    mp = self.manifest.manifestProject
+    dissociate = mp.config.GetBoolean('repo.dissociate')
+    if dissociate:
+      alternates_file = os.path.join(self.gitdir, 'objects/info/alternates')
+      if os.path.exists(alternates_file):
+        cmd = ['repack', '-a', '-d']
+        if GitCommand(self, cmd, bare=True).Wait() != 0:
+          return False
+        platform_utils.remove(alternates_file)
+
     if self.worktree:
       self._InitMRef()
     else: