[PATCH 4/4] nmbug: Add an 'init' command

["W. Trevor King" <wking@tremily.us>]

For folks that want to start versioning a new tag-space, instead of
cloning one that someone else has already started.

The empty-blob hash-object call avoids errors like:

  $ nmbug commit
  error: invalid object 100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 for 'tags/...'
  fatal: git-write-tree: error building trees
  'git HASH(0x9ef3eb8) write-tree' exited with nonzero value
---
 devel/nmbug/nmbug | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/devel/nmbug/nmbug b/devel/nmbug/nmbug
index c9ac046..b64dab9 100755
--- a/devel/nmbug/nmbug
+++ b/devel/nmbug/nmbug
@@ -30,6 +30,7 @@ my %command = (
 	     commit	=> \&do_commit,
 	     fetch	=> \&do_fetch,
 	     help	=> \&do_help,
+	     init	=> \&do_init,
 	     log	=> \&do_log,
 	     merge	=> \&do_merge,
 	     pull	=> \&do_pull,
@@ -152,6 +153,18 @@ sub do_clone {
   git ('config', 'core.bare', 'true');
 }
 
+sub do_init {
+  my $tempwork = tempdir ('/tmp/nmbug-init.XXXXXX', CLEANUP => 1);
+  system ('git', 'init', '--separate-git-dir', $NMBGIT, $tempwork) == 0
+    or die "'git init' exited with nonzero value\n";
+  git ('config', '--unset', 'core.worktree');
+  git ('config', 'core.bare', 'true');
+  # create an empty blob (e69de29bb2d1d6434b8b29ae775ad8c2e48c5391)
+  git ('hash-object', '-w', '--stdin');
+  git ( { GIT_WORK_TREE => $tempwork }, 'commit', '--allow-empty',
+        '-m', 'Start a new nmbug repository' );
+}
+
 sub is_committed {
   my $status = shift;
   return scalar (@{$status->{added}} ) + scalar (@{$status->{deleted}} ) == 0;
@@ -610,6 +623,12 @@ Create a local nmbug repository from a remote source.  This wraps
 C<git clone>, adding some options to avoid creating a working tree
 while preserving remote-tracking branches and upstreams.
 
+=item B<init>
+
+Create a local nmbug repository from scratch.  This wraps C<git init>
+and performs other setup to support subsequent status and commit
+commands.
+
 =item B<checkout>
 
 Update the notmuch database from git. This is mainly useful to discard
-- 
1.9.1.353.gc66d89d