Merge branch 'em/checkout-orphan'

* em/checkout-orphan:
  git checkout: create unparented branch by --orphan

1 files changed, 13 insertions, 2 deletions

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 88b1f43..c382521 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -33,6 +33,7 @@ struct checkout_opts {
 	int writeout_error;
 
 	const char *new_branch;
+	const char *new_orphan_branch;
 	int new_branch_log;
 	enum branch_track track;
 };
@@ -492,8 +493,9 @@ static void update_refs_for_switch(struct checkout_opts *opts,
 	struct strbuf msg = STRBUF_INIT;
 	const char *old_desc;
 	if (opts->new_branch) {
-		create_branch(old->name, opts->new_branch, new->name, 0,
-			      opts->new_branch_log, opts->track);
+		if (!opts->new_orphan_branch)
+			create_branch(old->name, opts->new_branch, new->name, 0,
+				      opts->new_branch_log, opts->track);
 		new->name = opts->new_branch;
 		setup_branch_path(new);
 	}
@@ -633,6 +635,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 		OPT_SET_INT('t', "track",  &opts.track, "track",
 			BRANCH_TRACK_EXPLICIT),
+		OPT_STRING(0, "orphan", &opts.new_orphan_branch, "new branch", "new unparented branch"),
 		OPT_SET_INT('2', "ours", &opts.writeout_stage, "stage",
 			    2),
 		OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
@@ -678,6 +681,14 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		opts.new_branch = argv0 + 1;
 	}
 
+	if (opts.new_orphan_branch) {
+		if (opts.new_branch)
+			die("--orphan and -b are mutually exclusive");
+		if (opts.track > 0 || opts.new_branch_log)
+			die("--orphan cannot be used with -t or -l");
+		opts.new_branch = opts.new_orphan_branch;
+	}
+
 	if (conflict_style) {
 		opts.merge = 1; /* implied */
 		git_xmerge_config("merge.conflictstyle", conflict_style, NULL);