1 files changed, 56 insertions, 22 deletions

diff --git a/branch.c b/branch.c
index b0024353f4..c50ea42172 100644
--- a/branch.c
+++ b/branch.c
@@ -4,6 +4,7 @@
 #include "refs.h"
 #include "remote.h"
 #include "commit.h"
+#include "worktree.h"
 
 struct tracking {
 	struct refspec spec;
@@ -48,7 +49,13 @@ static int should_setup_rebase(const char *origin)
 	return 0;
 }
 
-void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
+static const char tracking_advice[] =
+N_("\n"
+"After fixing the error cause you may try to fix up\n"
+"the remote tracking information by invoking\n"
+"\"git branch --set-upstream-to=%s%s%s\".");
+
+int install_branch_config(int flag, const char *local, const char *origin, const char *remote)
 {
 	const char *shortname = NULL;
 	struct strbuf key = STRBUF_INIT;
@@ -59,20 +66,23 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 	    && !origin) {
 		warning(_("Not setting branch %s as its own upstream."),
 			local);
-		return;
+		return 0;
 	}
 
 	strbuf_addf(&key, "branch.%s.remote", local);
-	git_config_set(key.buf, origin ? origin : ".");
+	if (git_config_set_gently(key.buf, origin ? origin : ".") < 0)
+		goto out_err;
 
 	strbuf_reset(&key);
 	strbuf_addf(&key, "branch.%s.merge", local);
-	git_config_set(key.buf, remote);
+	if (git_config_set_gently(key.buf, remote) < 0)
+		goto out_err;
 
 	if (rebasing) {
 		strbuf_reset(&key);
 		strbuf_addf(&key, "branch.%s.rebase", local);
-		git_config_set(key.buf, "true");
+		if (git_config_set_gently(key.buf, "true") < 0)
+			goto out_err;
 	}
 	strbuf_release(&key);
 
@@ -101,6 +111,19 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 					  local, remote);
 		}
 	}
+
+	return 0;
+
+out_err:
+	strbuf_release(&key);
+	error(_("Unable to write upstream branch configuration"));
+
+	advise(_(tracking_advice),
+	       origin ? origin : "",
+	       origin ? "/" : "",
+	       shortname ? shortname : remote);
+
+	return -1;
 }
 
 /*
@@ -108,8 +131,8 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
  * to infer the settings for branch.<new_ref>.{remote,merge} from the
  * config.
  */
-static int setup_tracking(const char *new_ref, const char *orig_ref,
-			  enum branch_track track, int quiet)
+static void setup_tracking(const char *new_ref, const char *orig_ref,
+			   enum branch_track track, int quiet)
 {
 	struct tracking tracking;
 	int config_flags = quiet ? 0 : BRANCH_CONFIG_VERBOSE;
@@ -117,7 +140,7 @@ static int setup_tracking(const char *new_ref, const char *orig_ref,
 	memset(&tracking, 0, sizeof(tracking));
 	tracking.spec.dst = (char *)orig_ref;
 	if (for_each_remote(find_tracked_branch, &tracking))
-		return 1;
+		return;
 
 	if (!tracking.matches)
 		switch (track) {
@@ -126,18 +149,18 @@ static int setup_tracking(const char *new_ref, const char *orig_ref,
 		case BRANCH_TRACK_OVERRIDE:
 			break;
 		default:
-			return 1;
+			return;
 		}
 
 	if (tracking.matches > 1)
-		return error(_("Not tracking: ambiguous information for ref %s"),
-				orig_ref);
+		die(_("Not tracking: ambiguous information for ref %s"),
+		    orig_ref);
 
-	install_branch_config(config_flags, new_ref, tracking.remote,
-			      tracking.src ? tracking.src : orig_ref);
+	if (install_branch_config(config_flags, new_ref, tracking.remote,
+			      tracking.src ? tracking.src : orig_ref) < 0)
+		exit(-1);
 
 	free(tracking.src);
-	return 0;
 }
 
 int read_branch_desc(struct strbuf *buf, const char *branch_name)
@@ -266,7 +289,7 @@ void create_branch(const char *head,
 
 	if ((commit = lookup_commit_reference(sha1)) == NULL)
 		die(_("Not a valid branch point: '%s'."), start_name);
-	hashcpy(sha1, commit->object.sha1);
+	hashcpy(sha1, commit->object.oid.hash);
 
 	if (forcing)
 		snprintf(msg, sizeof msg, "branch: Reset to %s",
@@ -302,11 +325,22 @@ void create_branch(const char *head,
 
 void remove_branch_state(void)
 {
-	unlink(git_path("CHERRY_PICK_HEAD"));
-	unlink(git_path("REVERT_HEAD"));
-	unlink(git_path("MERGE_HEAD"));
-	unlink(git_path("MERGE_RR"));
-	unlink(git_path("MERGE_MSG"));
-	unlink(git_path("MERGE_MODE"));
-	unlink(git_path("SQUASH_MSG"));
+	unlink(git_path_cherry_pick_head());
+	unlink(git_path_revert_head());
+	unlink(git_path_merge_head());
+	unlink(git_path_merge_rr());
+	unlink(git_path_merge_msg());
+	unlink(git_path_merge_mode());
+	unlink(git_path_squash_msg());
+}
+
+void die_if_checked_out(const char *branch)
+{
+	char *existing;
+
+	existing = find_shared_symref("HEAD", branch);
+	if (existing) {
+		skip_prefix(branch, "refs/heads/", &branch);
+		die(_("'%s' is already checked out at '%s'"), branch, existing);
+	}
 }