[PATCH 2/2] branch: warn and refuse to set a branch as a tracking branch of itself.

[Matthieu Moy <Matthieu.Moy@imag.fr>]

Previous patch allows commands like "git branch foo foo --track", which
doesn't make much sense. Warn the user and don't change the configuration
in this case. Don't die to let the caller finish its job in such case.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
---
 branch.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/branch.c b/branch.c
index d187891..d769c8a 100644
--- a/branch.c
+++ b/branch.c
@@ -49,9 +49,19 @@ static int should_setup_rebase(const char *origin)
 
 void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
 {
+	const char *shortname = remote + 11;
+	int remote_is_branch = !prefixcmp(remote, "refs/heads/");
 	struct strbuf key = STRBUF_INIT;
 	int rebasing = should_setup_rebase(origin);
 
+	if (remote_is_branch
+	    && !strcmp(local, shortname)
+	    && !origin) {
+		warning("Not setting branch %s as its own upstream.",
+			local);
+		return;
+	}
+
 	strbuf_addf(&key, "branch.%s.remote", local);
 	git_config_set(key.buf, origin ? origin : ".");
 
@@ -71,8 +81,8 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 		strbuf_addstr(&key, origin ? "remote" : "local");
 
 		/* Are we tracking a proper "branch"? */
-		if (!prefixcmp(remote, "refs/heads/")) {
-			strbuf_addf(&key, " branch %s", remote + 11);
+		if (remote_is_branch) {
+			strbuf_addf(&key, " branch %s", shortname);
 			if (origin)
 				strbuf_addf(&key, " from %s", origin);
 		}
-- 
1.6.6.198.gbaea2