add experimental git worktree support

This provides initial support for using git worktrees internally
instead of our own ad-hoc symlink tree.  It's been lightly tested
which is why it's not currently exposed via --help.

When people opt-in to worktrees in an existing repo client checkout,
no projects are migrated.  Instead, only new projects will use the
worktree method.  This allows for limited testing/opting in without
having to completely blow things away or get a second checkout.

Bug: https://crbug.com/gerrit/11486
Change-Id: Ic3ff891b30940a6ba497b406b2a387e0a8517ed8
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254075
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/repo b/repo
index 77e7fe90..743c28b3 100755
--- a/repo
+++ b/repo
@@ -302,6 +302,8 @@ def GetParser(gitc_init=False):
   group.add_option('--clone-filter', action='store', default='blob:none',
                    help='filter for use with --partial-clone '
                         '[default: %default]')
+  group.add_option('--worktree', action='store_true',
+                   help=optparse.SUPPRESS_HELP)
   group.add_option('--archive', action='store_true',
                    help='checkout an archive instead of a git repository for '
                         'each project. See git archive.')