1 files changed, 52 insertions, 19 deletions

diff --git a/builtin-branch.c b/builtin-branch.c
index 020ed6be7b..d0e7209368 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -275,7 +275,7 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 	}
 }
 
-static void print_ref_list(int kinds, int verbose, int abbrev)
+static void print_ref_list(int kinds, int detached, int verbose, int abbrev)
 {
 	int i;
 	struct ref_list ref_list;
@@ -286,8 +286,20 @@ static void print_ref_list(int kinds, int verbose, int abbrev)
 
 	qsort(ref_list.list, ref_list.index, sizeof(struct ref_item), ref_cmp);
 
+	detached = (detached && (kinds & REF_LOCAL_BRANCH));
+	if (detached) {
+		struct ref_item item;
+		item.name = "(no branch)";
+		item.kind = REF_LOCAL_BRANCH;
+		hashcpy(item.sha1, head_sha1);
+		if (strlen(item.name) > ref_list.maxwidth)
+			      ref_list.maxwidth = strlen(item.name);
+		print_ref_item(&item, ref_list.maxwidth, verbose, abbrev, 1);
+	}
+
 	for (i = 0; i < ref_list.index; i++) {
-		int current = (ref_list.list[i].kind == REF_LOCAL_BRANCH) &&
+		int current = !detached &&
+			(ref_list.list[i].kind == REF_LOCAL_BRANCH) &&
 			!strcmp(ref_list.list[i].name, head);
 		print_ref_item(&ref_list.list[i], ref_list.maxwidth, verbose,
 			       abbrev, current);
@@ -296,13 +308,15 @@ static void print_ref_list(int kinds, int verbose, int abbrev)
 	free_ref_list(&ref_list);
 }
 
-static void create_branch(const char *name, const char *start,
+static void create_branch(const char *name, const char *start_name,
+			  unsigned char *start_sha1,
 			  int force, int reflog)
 {
 	struct ref_lock *lock;
 	struct commit *commit;
 	unsigned char sha1[20];
 	char ref[PATH_MAX], msg[PATH_MAX + 20];
+	int forcing = 0;
 
 	snprintf(ref, sizeof ref, "refs/heads/%s", name);
 	if (check_ref_format(ref))
@@ -311,23 +325,34 @@ static void create_branch(const char *name, const char *start,
 	if (resolve_ref(ref, sha1, 1, NULL)) {
 		if (!force)
 			die("A branch named '%s' already exists.", name);
-		else if (!strcmp(head, name))
+		else if (!is_bare_repository() && !strcmp(head, name))
 			die("Cannot force update the current branch.");
+		forcing = 1;
 	}
 
-	if (get_sha1(start, sha1) ||
-	    (commit = lookup_commit_reference(sha1)) == NULL)
-		die("Not a valid branch point: '%s'.", start);
+	if (start_sha1)
+		/* detached HEAD */
+		hashcpy(sha1, start_sha1);
+	else if (get_sha1(start_name, sha1))
+		die("Not a valid object name: '%s'.", start_name);
+
+	if ((commit = lookup_commit_reference(sha1)) == NULL)
+		die("Not a valid branch point: '%s'.", start_name);
 	hashcpy(sha1, commit->object.sha1);
 
 	lock = lock_any_ref_for_update(ref, NULL);
 	if (!lock)
 		die("Failed to lock ref for update: %s.", strerror(errno));
 
-	if (reflog) {
+	if (reflog)
 		log_all_ref_updates = 1;
-		snprintf(msg, sizeof msg, "branch: Created from %s", start);
-	}
+
+	if (forcing)
+		snprintf(msg, sizeof msg, "branch: Reset from %s",
+			 start_name);
+	else
+		snprintf(msg, sizeof msg, "branch: Created from %s",
+			 start_name);
 
 	if (write_ref_sha1(lock, sha1, msg) < 0)
 		die("Failed to write ref: %s.", strerror(errno));
@@ -338,6 +363,9 @@ static void rename_branch(const char *oldname, const char *newname, int force)
 	char oldref[PATH_MAX], newref[PATH_MAX], logmsg[PATH_MAX*2 + 100];
 	unsigned char sha1[20];
 
+	if (!oldname)
+		die("cannot rename the current branch while not on any.");
+
 	if (snprintf(oldref, sizeof(oldref), "refs/heads/%s", oldname) > sizeof(oldref))
 		die("Old branchname too long");
 
@@ -359,7 +387,8 @@ static void rename_branch(const char *oldname, const char *newname, int force)
 	if (rename_ref(oldref, newref, logmsg))
 		die("Branch rename failed");
 
-	if (!strcmp(oldname, head) && create_symref("HEAD", newref))
+	/* no need to pass logmsg here as HEAD didn't really move */
+	if (!strcmp(oldname, head) && create_symref("HEAD", newref, NULL))
 		die("Branch renamed to %s, but HEAD is not updated!", newname);
 }
 
@@ -367,12 +396,11 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 {
 	int delete = 0, force_delete = 0, force_create = 0;
 	int rename = 0, force_rename = 0;
-	int verbose = 0, abbrev = DEFAULT_ABBREV;
+	int verbose = 0, abbrev = DEFAULT_ABBREV, detached = 0;
 	int reflog = 0;
 	int kinds = REF_LOCAL_BRANCH;
 	int i;
 
-	setup_ident();
 	git_config(git_branch_config);
 
 	for (i = 1; i < argc; i++) {
@@ -444,22 +472,27 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	head = xstrdup(resolve_ref("HEAD", head_sha1, 0, NULL));
 	if (!head)
 		die("Failed to resolve HEAD as a valid ref.");
-	if (strncmp(head, "refs/heads/", 11))
-		die("HEAD not found below refs/heads!");
-	head += 11;
+	if (!strcmp(head, "HEAD")) {
+		detached = 1;
+	}
+	else {
+		if (strncmp(head, "refs/heads/", 11))
+			die("HEAD not found below refs/heads!");
+		head += 11;
+	}
 
 	if (delete)
 		return delete_branches(argc - i, argv + i, force_delete, kinds);
 	else if (i == argc)
-		print_ref_list(kinds, verbose, abbrev);
+		print_ref_list(kinds, detached, verbose, abbrev);
 	else if (rename && (i == argc - 1))
 		rename_branch(head, argv[i], force_rename);
 	else if (rename && (i == argc - 2))
 		rename_branch(argv[i], argv[i + 1], force_rename);
 	else if (i == argc - 1)
-		create_branch(argv[i], head, force_create, reflog);
+		create_branch(argv[i], head, head_sha1, force_create, reflog);
 	else if (i == argc - 2)
-		create_branch(argv[i], argv[i + 1], force_create, reflog);
+		create_branch(argv[i], argv[i+1], NULL, force_create, reflog);
 	else
 		usage(builtin_branch_usage);