1 files changed, 259 insertions, 101 deletions

diff --git a/builtin/branch.c b/builtin/branch.c
index 0e060f2e4a..083689063f 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -17,12 +17,14 @@
 #include "revision.h"
 #include "string-list.h"
 #include "column.h"
+#include "utf8.h"
+#include "wt-status.h"
 
 static const char * const builtin_branch_usage[] = {
-	"git branch [options] [-r | -a] [--merged | --no-merged]",
-	"git branch [options] [-l] [-f] <branchname> [<start-point>]",
-	"git branch [options] [-r] (-d | -D) <branchname>...",
-	"git branch [options] (-m | -M) [<oldbranch>] <newbranch>",
+	N_("git branch [options] [-r | -a] [--merged | --no-merged]"),
+	N_("git branch [options] [-l] [-f] <branchname> [<start-point>]"),
+	N_("git branch [options] [-r] (-d | -D) <branchname>..."),
+	N_("git branch [options] (-m | -M) [<oldbranch>] <newbranch>"),
 	NULL
 };
 
@@ -39,13 +41,15 @@ static char branch_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RED,		/* REMOTE */
 	GIT_COLOR_NORMAL,	/* LOCAL */
 	GIT_COLOR_GREEN,	/* CURRENT */
+	GIT_COLOR_BLUE,		/* UPSTREAM */
 };
 enum color_branch {
 	BRANCH_COLOR_RESET = 0,
 	BRANCH_COLOR_PLAIN = 1,
 	BRANCH_COLOR_REMOTE = 2,
 	BRANCH_COLOR_LOCAL = 3,
-	BRANCH_COLOR_CURRENT = 4
+	BRANCH_COLOR_CURRENT = 4,
+	BRANCH_COLOR_UPSTREAM = 5
 };
 
 static enum merge_filter {
@@ -70,6 +74,8 @@ static int parse_branch_color_slot(const char *var, int ofs)
 		return BRANCH_COLOR_LOCAL;
 	if (!strcasecmp(var+ofs, "current"))
 		return BRANCH_COLOR_CURRENT;
+	if (!strcasecmp(var+ofs, "upstream"))
+		return BRANCH_COLOR_UPSTREAM;
 	return -1;
 }
 
@@ -129,7 +135,7 @@ static int branch_merged(int kind, const char *name,
 	if (!reference_rev)
 		reference_rev = head_rev;
 
-	merged = in_merge_bases(rev, &reference_rev, 1);
+	merged = in_merge_bases(rev, reference_rev);
 
 	/*
 	 * After the safety valve is fully redefined to "check with
@@ -139,7 +145,7 @@ static int branch_merged(int kind, const char *name,
 	 * a gentle reminder is in order.
 	 */
 	if ((head_rev != reference_rev) &&
-	    in_merge_bases(rev, &head_rev, 1) != merged) {
+	    in_merge_bases(rev, head_rev) != merged) {
 		if (merged)
 			warning(_("deleting branch '%s' that has been merged to\n"
 				"         '%s', but not yet merged to HEAD."),
@@ -153,10 +159,37 @@ static int branch_merged(int kind, const char *name,
 	return merged;
 }
 
+static int check_branch_commit(const char *branchname, const char *refname,
+			       unsigned char *sha1, struct commit *head_rev,
+			       int kinds, int force)
+{
+	struct commit *rev = lookup_commit_reference(sha1);
+	if (!rev) {
+		error(_("Couldn't look up commit object for '%s'"), refname);
+		return -1;
+	}
+	if (!force && !branch_merged(kinds, branchname, rev, head_rev)) {
+		error(_("The branch '%s' is not fully merged.\n"
+		      "If you are sure you want to delete it, "
+		      "run 'git branch -D %s'."), branchname, branchname);
+		return -1;
+	}
+	return 0;
+}
+
+static void delete_branch_config(const char *branchname)
+{
+	struct strbuf buf = STRBUF_INIT;
+	strbuf_addf(&buf, "branch.%s", branchname);
+	if (git_config_rename_section(buf.buf, NULL) < 0)
+		warning(_("Update of config-file failed"));
+	strbuf_release(&buf);
+}
+
 static int delete_branches(int argc, const char **argv, int force, int kinds,
 			   int quiet)
 {
-	struct commit *rev, *head_rev = NULL;
+	struct commit *head_rev = NULL;
 	unsigned char sha1[20];
 	char *name = NULL;
 	const char *fmt;
@@ -186,6 +219,9 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			die(_("Couldn't look up commit object for HEAD"));
 	}
 	for (i = 0; i < argc; i++, strbuf_release(&bname)) {
+		const char *target;
+		int flags = 0;
+
 		strbuf_branchname(&bname, argv[i]);
 		if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {
 			error(_("Cannot delete the branch '%s' "
@@ -196,8 +232,10 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 
 		free(name);
 
-		name = xstrdup(mkpath(fmt, bname.buf));
-		if (read_ref(name, sha1)) {
+		name = mkpathdup(fmt, bname.buf);
+		target = resolve_ref_unsafe(name, sha1, 0, &flags);
+		if (!target ||
+		    (!(flags & REF_ISSYMREF) && is_null_sha1(sha1))) {
 			error(remote_branch
 			      ? _("remote branch '%s' not found.")
 			      : _("branch '%s' not found."), bname.buf);
@@ -205,40 +243,31 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			continue;
 		}
 
-		rev = lookup_commit_reference(sha1);
-		if (!rev) {
-			error(_("Couldn't look up commit object for '%s'"), name);
+		if (!(flags & REF_ISSYMREF) &&
+		    check_branch_commit(bname.buf, name, sha1, head_rev, kinds,
+					force)) {
 			ret = 1;
 			continue;
 		}
 
-		if (!force && !branch_merged(kinds, bname.buf, rev, head_rev)) {
-			error(_("The branch '%s' is not fully merged.\n"
-			      "If you are sure you want to delete it, "
-			      "run 'git branch -D %s'."), bname.buf, bname.buf);
-			ret = 1;
-			continue;
-		}
-
-		if (delete_ref(name, sha1, 0)) {
+		if (delete_ref(name, sha1, REF_NODEREF)) {
 			error(remote_branch
 			      ? _("Error deleting remote branch '%s'")
 			      : _("Error deleting branch '%s'"),
 			      bname.buf);
 			ret = 1;
-		} else {
-			struct strbuf buf = STRBUF_INIT;
-			if (!quiet)
-				printf(remote_branch
-				       ? _("Deleted remote branch %s (was %s).\n")
-				       : _("Deleted branch %s (was %s).\n"),
-				       bname.buf,
-				       find_unique_abbrev(sha1, DEFAULT_ABBREV));
-			strbuf_addf(&buf, "branch.%s", bname.buf);
-			if (git_config_rename_section(buf.buf, NULL) < 0)
-				warning(_("Update of config-file failed"));
-			strbuf_release(&buf);
+			continue;
+		}
+		if (!quiet) {
+			printf(remote_branch
+			       ? _("Deleted remote branch %s (was %s).\n")
+			       : _("Deleted branch %s (was %s).\n"),
+			       bname.buf,
+			       (flags & REF_ISSYMREF)
+			       ? target
+			       : find_unique_abbrev(sha1, DEFAULT_ABBREV));
 		}
+		delete_branch_config(bname.buf);
 	}
 
 	free(name);
@@ -249,7 +278,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 struct ref_item {
 	char *name;
 	char *dest;
-	unsigned int kind, len;
+	unsigned int kind, width;
 	struct commit *commit;
 };
 
@@ -354,14 +383,14 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	newitem->name = xstrdup(refname);
 	newitem->kind = kind;
 	newitem->commit = commit;
-	newitem->len = strlen(refname);
+	newitem->width = utf8_strwidth(refname);
 	newitem->dest = resolve_symref(orig_refname, prefix);
 	/* adjust for "remotes/" */
 	if (newitem->kind == REF_REMOTE_BRANCH &&
 	    ref_list->kinds != REF_REMOTE_BRANCH)
-		newitem->len += 8;
-	if (newitem->len > ref_list->maxwidth)
-		ref_list->maxwidth = newitem->len;
+		newitem->width += 8;
+	if (newitem->width > ref_list->maxwidth)
+		ref_list->maxwidth = newitem->width;
 
 	return 0;
 }
@@ -393,36 +422,52 @@ static void fill_tracking_info(struct strbuf *stat, const char *branch_name,
 	int ours, theirs;
 	char *ref = NULL;
 	struct branch *branch = branch_get(branch_name);
+	struct strbuf fancy = STRBUF_INIT;
 
 	if (!stat_tracking_info(branch, &ours, &theirs)) {
 		if (branch && branch->merge && branch->merge[0]->dst &&
-		    show_upstream_ref)
-			strbuf_addf(stat, "[%s] ",
-			    shorten_unambiguous_ref(branch->merge[0]->dst, 0));
+		    show_upstream_ref) {
+			ref = shorten_unambiguous_ref(branch->merge[0]->dst, 0);
+			if (want_color(branch_use_color))
+				strbuf_addf(stat, "[%s%s%s] ",
+						branch_get_color(BRANCH_COLOR_UPSTREAM),
+						ref, branch_get_color(BRANCH_COLOR_RESET));
+			else
+				strbuf_addf(stat, "[%s] ", ref);
+		}
 		return;
 	}
 
-	if (show_upstream_ref)
+	if (show_upstream_ref) {
 		ref = shorten_unambiguous_ref(branch->merge[0]->dst, 0);
+		if (want_color(branch_use_color))
+			strbuf_addf(&fancy, "%s%s%s",
+					branch_get_color(BRANCH_COLOR_UPSTREAM),
+					ref, branch_get_color(BRANCH_COLOR_RESET));
+		else
+			strbuf_addstr(&fancy, ref);
+	}
+
 	if (!ours) {
 		if (ref)
-			strbuf_addf(stat, _("[%s: behind %d]"), ref, theirs);
+			strbuf_addf(stat, _("[%s: behind %d]"), fancy.buf, theirs);
 		else
 			strbuf_addf(stat, _("[behind %d]"), theirs);
 
 	} else if (!theirs) {
 		if (ref)
-			strbuf_addf(stat, _("[%s: ahead %d]"), ref, ours);
+			strbuf_addf(stat, _("[%s: ahead %d]"), fancy.buf, ours);
 		else
 			strbuf_addf(stat, _("[ahead %d]"), ours);
 	} else {
 		if (ref)
 			strbuf_addf(stat, _("[%s: ahead %d, behind %d]"),
-				    ref, ours, theirs);
+				    fancy.buf, ours, theirs);
 		else
 			strbuf_addf(stat, _("[ahead %d, behind %d]"),
 				    ours, theirs);
 	}
+	strbuf_release(&fancy);
 	strbuf_addch(stat, ' ');
 	free(ref);
 }
@@ -442,7 +487,7 @@ static void add_verbose_info(struct strbuf *out, struct ref_item *item,
 			     int verbose, int abbrev)
 {
 	struct strbuf subject = STRBUF_INIT, stat = STRBUF_INIT;
-	const char *sub = " **** invalid ref ****";
+	const char *sub = _(" **** invalid ref ****");
 	struct commit *commit = item->commit;
 
 	if (commit && !parse_commit(commit)) {
@@ -490,11 +535,12 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 	}
 
 	strbuf_addf(&name, "%s%s", prefix, item->name);
-	if (verbose)
+	if (verbose) {
+		int utf8_compensation = strlen(name.buf) - utf8_strwidth(name.buf);
 		strbuf_addf(&out, "%c %s%-*s%s", c, branch_get_color(color),
-			    maxwidth, name.buf,
+			    maxwidth + utf8_compensation, name.buf,
 			    branch_get_color(BRANCH_COLOR_RESET));
-	else
+	} else
 		strbuf_addf(&out, "%c %s%s%s", c, branch_get_color(color),
 			    name.buf, branch_get_color(BRANCH_COLOR_RESET));
 
@@ -519,12 +565,35 @@ static int calc_maxwidth(struct ref_list *refs)
 	for (i = 0; i < refs->index; i++) {
 		if (!matches_merge_filter(refs->list[i].commit))
 			continue;
-		if (refs->list[i].len > w)
-			w = refs->list[i].len;
+		if (refs->list[i].width > w)
+			w = refs->list[i].width;
 	}
 	return w;
 }
 
+static char *get_head_description(void)
+{
+	struct strbuf desc = STRBUF_INIT;
+	struct wt_status_state state;
+	memset(&state, 0, sizeof(state));
+	wt_status_get_state(&state, 1);
+	if (state.rebase_in_progress ||
+	    state.rebase_interactive_in_progress)
+		strbuf_addf(&desc, _("(no branch, rebasing %s)"),
+			    state.branch);
+	else if (state.bisect_in_progress)
+		strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
+			    state.branch);
+	else if (state.detached_from)
+		strbuf_addf(&desc, _("(detached from %s)"),
+			    state.detached_from);
+	else
+		strbuf_addstr(&desc, _("(no branch)"));
+	free(state.branch);
+	free(state.onto);
+	free(state.detached_from);
+	return strbuf_detach(&desc, NULL);
+}
 
 static void show_detached(struct ref_list *ref_list)
 {
@@ -532,13 +601,13 @@ static void show_detached(struct ref_list *ref_list)
 
 	if (head_commit && is_descendant_of(head_commit, ref_list->with_commit)) {
 		struct ref_item item;
-		item.name = xstrdup(_("(no branch)"));
-		item.len = strlen(item.name);
+		item.name = get_head_description();
+		item.width = utf8_strwidth(item.name);
 		item.kind = REF_LOCAL_BRANCH;
 		item.dest = NULL;
 		item.commit = head_commit;
-		if (item.len > ref_list->maxwidth)
-			ref_list->maxwidth = item.len;
+		if (item.width > ref_list->maxwidth)
+			ref_list->maxwidth = item.width;
 		print_ref_item(&item, ref_list->maxwidth, ref_list->verbose, ref_list->abbrev, 1, "");
 		free(item.name);
 	}
@@ -565,7 +634,7 @@ static int print_ref_list(int kinds, int detached, int verbose, int abbrev, stru
 		struct commit *filter;
 		filter = lookup_commit_reference_gently(merge_filter_ref, 0);
 		if (!filter)
-			die("object '%s' does not point to a commit",
+			die(_("object '%s' does not point to a commit"),
 			    sha1_to_hex(merge_filter_ref));
 
 		filter->object.flags |= UNINTERESTING;
@@ -681,11 +750,11 @@ static int edit_branch_description(const char *branch_name)
 	read_branch_desc(&buf, branch_name);
 	if (!buf.len || buf.buf[buf.len-1] != '\n')
 		strbuf_addch(&buf, '\n');
-	strbuf_addf(&buf,
-		    "# Please edit the description for the branch\n"
-		    "#   %s\n"
-		    "# Lines starting with '#' will be stripped.\n",
-		    branch_name);
+	strbuf_commented_addf(&buf,
+		    "Please edit the description for the branch\n"
+		    "  %s\n"
+		    "Lines starting with '%c' will be stripped.\n",
+		    branch_name, comment_line_char);
 	fp = fopen(git_path(edit_description), "w");
 	if ((fwrite(buf.buf, 1, buf.len, fp) < buf.len) || fclose(fp)) {
 		strbuf_release(&buf);
@@ -700,7 +769,7 @@ static int edit_branch_description(const char *branch_name)
 	stripspace(&buf, 1);
 
 	strbuf_addf(&name, "branch.%s.description", branch_name);
-	status = git_config_set(name.buf, buf.buf);
+	status = git_config_set(name.buf, buf.len ? buf.buf : NULL);
 	strbuf_release(&name);
 	strbuf_release(&buf);
 
@@ -712,62 +781,65 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	int delete = 0, rename = 0, force_create = 0, list = 0;
 	int verbose = 0, abbrev = -1, detached = 0;
 	int reflog = 0, edit_description = 0;
-	int quiet = 0;
+	int quiet = 0, unset_upstream = 0;
+	const char *new_upstream = NULL;
 	enum branch_track track;
 	int kinds = REF_LOCAL_BRANCH;
 	struct commit_list *with_commit = NULL;
 
 	struct option options[] = {
-		OPT_GROUP("Generic options"),
+		OPT_GROUP(N_("Generic options")),
 		OPT__VERBOSE(&verbose,
-			"show hash and subject, give twice for upstream branch"),
-		OPT__QUIET(&quiet, "suppress informational messages"),
-		OPT_SET_INT('t', "track",  &track, "set up tracking mode (see git-pull(1))",
+			N_("show hash and subject, give twice for upstream branch")),
+		OPT__QUIET(&quiet, N_("suppress informational messages")),
+		OPT_SET_INT('t', "track",  &track, N_("set up tracking mode (see git-pull(1))"),
 			BRANCH_TRACK_EXPLICIT),
-		OPT_SET_INT( 0, "set-upstream",  &track, "change upstream info",
+		OPT_SET_INT( 0, "set-upstream",  &track, N_("change upstream info"),
 			BRANCH_TRACK_OVERRIDE),
-		OPT__COLOR(&branch_use_color, "use colored output"),
-		OPT_SET_INT('r', "remotes",     &kinds, "act on remote-tracking branches",
+		OPT_STRING('u', "set-upstream-to", &new_upstream, "upstream", "change the upstream info"),
+		OPT_BOOLEAN(0, "unset-upstream", &unset_upstream, "Unset the upstream info"),
+		OPT__COLOR(&branch_use_color, N_("use colored output")),
+		OPT_SET_INT('r', "remotes",     &kinds, N_("act on remote-tracking branches"),
 			REF_REMOTE_BRANCH),
 		{
-			OPTION_CALLBACK, 0, "contains", &with_commit, "commit",
-			"print only branches that contain the commit",
+			OPTION_CALLBACK, 0, "contains", &with_commit, N_("commit"),
+			N_("print only branches that contain the commit"),
 			PARSE_OPT_LASTARG_DEFAULT,
 			parse_opt_with_commit, (intptr_t)"HEAD",
 		},
 		{
-			OPTION_CALLBACK, 0, "with", &with_commit, "commit",
-			"print only branches that contain the commit",
+			OPTION_CALLBACK, 0, "with", &with_commit, N_("commit"),
+			N_("print only branches that contain the commit"),
 			PARSE_OPT_HIDDEN | PARSE_OPT_LASTARG_DEFAULT,
 			parse_opt_with_commit, (intptr_t) "HEAD",
 		},
 		OPT__ABBREV(&abbrev),
 
-		OPT_GROUP("Specific git-branch actions:"),
-		OPT_SET_INT('a', "all", &kinds, "list both remote-tracking and local branches",
+		OPT_GROUP(N_("Specific git-branch actions:")),
+		OPT_SET_INT('a', "all", &kinds, N_("list both remote-tracking and local branches"),
 			REF_REMOTE_BRANCH | REF_LOCAL_BRANCH),
-		OPT_BIT('d', "delete", &delete, "delete fully merged branch", 1),
-		OPT_BIT('D', NULL, &delete, "delete branch (even if not merged)", 2),
-		OPT_BIT('m', "move", &rename, "move/rename a branch and its reflog", 1),
-		OPT_BIT('M', NULL, &rename, "move/rename a branch, even if target exists", 2),
-		OPT_BOOLEAN(0, "list", &list, "list branch names"),
-		OPT_BOOLEAN('l', "create-reflog", &reflog, "create the branch's reflog"),
+		OPT_BIT('d', "delete", &delete, N_("delete fully merged branch"), 1),
+		OPT_BIT('D', NULL, &delete, N_("delete branch (even if not merged)"), 2),
+		OPT_BIT('m', "move", &rename, N_("move/rename a branch and its reflog"), 1),
+		OPT_BIT('M', NULL, &rename, N_("move/rename a branch, even if target exists"), 2),
+		OPT_BOOLEAN(0, "list", &list, N_("list branch names")),
+		OPT_BOOLEAN('l', "create-reflog", &reflog, N_("create the branch's reflog")),
 		OPT_BOOLEAN(0, "edit-description", &edit_description,
-			    "edit the description for the branch"),
-		OPT__FORCE(&force_create, "force creation (when already exists)"),
+			    N_("edit the description for the branch")),
+		OPT__FORCE(&force_create, N_("force creation (when already exists)")),
 		{
 			OPTION_CALLBACK, 0, "no-merged", &merge_filter_ref,
-			"commit", "print only not merged branches",
+			N_("commit"), N_("print only not merged branches"),
 			PARSE_OPT_LASTARG_DEFAULT | PARSE_OPT_NONEG,
 			opt_parse_merge_filter, (intptr_t) "HEAD",
 		},
 		{
 			OPTION_CALLBACK, 0, "merged", &merge_filter_ref,
-			"commit", "print only merged branches",
+			N_("commit"), N_("print only merged branches"),
 			PARSE_OPT_LASTARG_DEFAULT | PARSE_OPT_NONEG,
 			opt_parse_merge_filter, (intptr_t) "HEAD",
 		},
-		OPT_COLUMN(0, "column", &colopts, "list branches in columns"),
+		OPT_COLUMN(0, "column", &colopts, N_("list branches in columns")),
 		OPT_END(),
 	};
 
@@ -794,10 +866,13 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, builtin_branch_usage,
 			     0);
 
-	if (!delete && !rename && !edit_description && argc == 0)
+	if (!delete && !rename && !edit_description && !new_upstream && !unset_upstream && argc == 0)
 		list = 1;
 
-	if (!!delete + !!rename + !!force_create + !!list > 1)
+	if (with_commit || merge_filter != NO_FILTER)
+		list = 1;
+
+	if (!!delete + !!rename + !!force_create + !!list + !!new_upstream + !!unset_upstream > 1)
 		usage_with_options(builtin_branch_usage, options);
 
 	if (abbrev == -1)
@@ -809,9 +884,11 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		colopts = 0;
 	}
 
-	if (delete)
+	if (delete) {
+		if (!argc)
+			die(_("branch name required"));
 		return delete_branches(argc, argv, delete > 1, kinds, quiet);
-	else if (list) {
+	} else if (list) {
 		int ret = print_ref_list(kinds, detached, verbose, abbrev,
 					 with_commit, argv);
 		print_columns(&output, colopts, NULL);
@@ -822,41 +899,122 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		const char *branch_name;
 		struct strbuf branch_ref = STRBUF_INIT;
 
-		if (detached)
-			die("Cannot give description to detached HEAD");
-		if (!argc)
+		if (!argc) {
+			if (detached)
+				die(_("Cannot give description to detached HEAD"));
 			branch_name = head;
-		else if (argc == 1)
+		} else if (argc == 1)
 			branch_name = argv[0];
 		else
-			usage_with_options(builtin_branch_usage, options);
+			die(_("cannot edit description of more than one branch"));
 
 		strbuf_addf(&branch_ref, "refs/heads/%s", branch_name);
 		if (!ref_exists(branch_ref.buf)) {
 			strbuf_release(&branch_ref);
 
 			if (!argc)
-				return error("No commit on branch '%s' yet.",
+				return error(_("No commit on branch '%s' yet."),
 					     branch_name);
 			else
-				return error("No such branch '%s'.", branch_name);
+				return error(_("No branch named '%s'."),
+					     branch_name);
 		}
 		strbuf_release(&branch_ref);
 
 		if (edit_branch_description(branch_name))
 			return 1;
 	} else if (rename) {
-		if (argc == 1)
+		if (!argc)
+			die(_("branch name required"));
+		else if (argc == 1)
 			rename_branch(head, argv[0], rename > 1);
 		else if (argc == 2)
 			rename_branch(argv[0], argv[1], rename > 1);
 		else
-			usage_with_options(builtin_branch_usage, options);
+			die(_("too many branches for a rename operation"));
+	} else if (new_upstream) {
+		struct branch *branch = branch_get(argv[0]);
+
+		if (argc > 1)
+			die(_("too many branches to set new upstream"));
+
+		if (!branch) {
+			if (!argc || !strcmp(argv[0], "HEAD"))
+				die(_("could not set upstream of HEAD to %s when "
+				      "it does not point to any branch."),
+				    new_upstream);
+			die(_("no such branch '%s'"), argv[0]);
+		}
+
+		if (!ref_exists(branch->refname))
+			die(_("branch '%s' does not exist"), branch->name);
+
+		/*
+		 * create_branch takes care of setting up the tracking
+		 * info and making sure new_upstream is correct
+		 */
+		create_branch(head, branch->name, new_upstream, 0, 0, 0, quiet, BRANCH_TRACK_OVERRIDE);
+	} else if (unset_upstream) {
+		struct branch *branch = branch_get(argv[0]);
+		struct strbuf buf = STRBUF_INIT;
+
+		if (argc > 1)
+			die(_("too many branches to unset upstream"));
+
+		if (!branch) {
+			if (!argc || !strcmp(argv[0], "HEAD"))
+				die(_("could not unset upstream of HEAD when "
+				      "it does not point to any branch."));
+			die(_("no such branch '%s'"), argv[0]);
+		}
+
+		if (!branch_has_merge_config(branch)) {
+			die(_("Branch '%s' has no upstream information"), branch->name);
+		}
+
+		strbuf_addf(&buf, "branch.%s.remote", branch->name);
+		git_config_set_multivar(buf.buf, NULL, NULL, 1);
+		strbuf_reset(&buf);
+		strbuf_addf(&buf, "branch.%s.merge", branch->name);
+		git_config_set_multivar(buf.buf, NULL, NULL, 1);
+		strbuf_release(&buf);
 	} else if (argc > 0 && argc <= 2) {
+		struct branch *branch = branch_get(argv[0]);
+		int branch_existed = 0, remote_tracking = 0;
+		struct strbuf buf = STRBUF_INIT;
+
+		if (!strcmp(argv[0], "HEAD"))
+			die(_("it does not make sense to create 'HEAD' manually"));
+
+		if (!branch)
+			die(_("no such branch '%s'"), argv[0]);
+
 		if (kinds != REF_LOCAL_BRANCH)
 			die(_("-a and -r options to 'git branch' do not make sense with a branch name"));
+
+		if (track == BRANCH_TRACK_OVERRIDE)
+			fprintf(stderr, _("The --set-upstream flag is deprecated and will be removed. Consider using --track or --set-upstream-to\n"));
+
+		strbuf_addf(&buf, "refs/remotes/%s", branch->name);
+		remote_tracking = ref_exists(buf.buf);
+		strbuf_release(&buf);
+
+		branch_existed = ref_exists(branch->refname);
 		create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
 			      force_create, reflog, 0, quiet, track);
+
+		/*
+		 * We only show the instructions if the user gave us
+		 * one branch which doesn't exist locally, but is the
+		 * name of a remote-tracking branch.
+		 */
+		if (argc == 1 && track == BRANCH_TRACK_OVERRIDE &&
+		    !branch_existed && remote_tracking) {
+			fprintf(stderr, _("\nIf you wanted to make '%s' track '%s', do this:\n\n"), head, branch->name);
+			fprintf(stderr, _("    git branch -d %s\n"), branch->name);
+			fprintf(stderr, _("    git branch --set-upstream-to %s\n"), branch->name);
+		}
+
 	} else
 		usage_with_options(builtin_branch_usage, options);