Merge branch 'jc/branch-previous'

* jc/branch-previous:
  Teach @{-1} to git merge
  Teach the "@{-1} syntax to "git branch"

branch.c

@@ -103,14 +103,22 @@ void create_branch(const char *head,
 	struct ref_lock *lock;
 	struct commit *commit;
 	unsigned char sha1[20];
-	char *real_ref, ref[PATH_MAX], msg[PATH_MAX + 20];
+	char *real_ref, msg[PATH_MAX + 20];
+	struct strbuf ref = STRBUF_INIT;
 	int forcing = 0;
+	int len;
 
-	snprintf(ref, sizeof ref, "refs/heads/%s", name);
+	len = strlen(name);
-	if (check_ref_format(ref))
+	if (interpret_nth_last_branch(name, &ref) != len) {
+		strbuf_reset(&ref);
+		strbuf_add(&ref, name, len);
+	}
+	strbuf_splice(&ref, 0, 0, "refs/heads/", 11);
+
+	if (check_ref_format(ref.buf))
 		die("'%s' is not a valid branch name.", name);
 
-	if (resolve_ref(ref, sha1, 1, NULL)) {
+	if (resolve_ref(ref.buf, sha1, 1, NULL)) {
 		if (!force)
 			die("A branch named '%s' already exists.", name);
 		else if (!is_bare_repository() && !strcmp(head, name))
@@ -142,7 +150,7 @@ void create_branch(const char *head,
 		die("Not a valid branch point: '%s'.", start_name);
 	hashcpy(sha1, commit->object.sha1);
 
-	lock = lock_any_ref_for_update(ref, NULL, 0);
+	lock = lock_any_ref_for_update(ref.buf, NULL, 0);
 	if (!lock)
 		die("Failed to lock ref for update: %s.", strerror(errno));
 
@@ -162,6 +170,7 @@ void create_branch(const char *head,
 	if (write_ref_sha1(lock, sha1, msg) < 0)
 		die("Failed to write ref: %s.", strerror(errno));
 
+	strbuf_release(&ref);
 	free(real_ref);
 }
 

builtin-branch.c

@@ -99,6 +99,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 	const char *fmt, *remote;
 	int i;
 	int ret = 0;
+	struct strbuf bname = STRBUF_INIT;
 
 	switch (kinds) {
 	case REF_REMOTE_BRANCH:
@@ -119,20 +120,25 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 		if (!head_rev)
 			die("Couldn't look up commit object for HEAD");
 	}
-	for (i = 0; i < argc; i++) {
+	for (i = 0; i < argc; i++, strbuf_release(&bname)) {
-		if (kinds == REF_LOCAL_BRANCH && !strcmp(head, argv[i])) {
+		int len = strlen(argv[i]);
+
+		if (interpret_nth_last_branch(argv[i], &bname) != len)
+			strbuf_add(&bname, argv[i], len);
+
+		if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {
 			error("Cannot delete the branch '%s' "
-				"which you are currently on.", argv[i]);
+			      "which you are currently on.", bname.buf);
 			ret = 1;
 			continue;
 		}
 
 		free(name);
 
-		name = xstrdup(mkpath(fmt, argv[i]));
+		name = xstrdup(mkpath(fmt, bname.buf));
 		if (!resolve_ref(name, sha1, 1, NULL)) {
 			error("%sbranch '%s' not found.",
-					remote, argv[i]);
+					remote, bname.buf);
 			ret = 1;
 			continue;
 		}
@@ -154,20 +160,21 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 			error("The branch '%s' is not an ancestor of "
 			      "your current HEAD.\n"
 			      "If you are sure you want to delete it, "
-				"run 'git branch -D %s'.", argv[i], argv[i]);
+			      "run 'git branch -D %s'.", bname.buf, bname.buf);
 			ret = 1;
 			continue;
 		}
 
 		if (delete_ref(name, sha1, 0)) {
 			error("Error deleting %sbranch '%s'", remote,
-			       argv[i]);
+			      bname.buf);
 			ret = 1;
 		} else {
 			struct strbuf buf = STRBUF_INIT;
-			printf("Deleted %sbranch %s (%s).\n", remote, argv[i],
+			printf("Deleted %sbranch %s (%s).\n", remote,
+			       bname.buf,
 			       find_unique_abbrev(sha1, DEFAULT_ABBREV));
-			strbuf_addf(&buf, "branch.%s", argv[i]);
+			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);

builtin-merge.c

@@ -356,9 +356,14 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	struct object *remote_head;
 	unsigned char branch_head[20], buf_sha[20];
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf bname = STRBUF_INIT;
 	const char *ptr;
 	int len, early;
 
+	len = strlen(remote);
+	if (interpret_nth_last_branch(remote, &bname) == len)
+		remote = bname.buf;
+
 	memset(branch_head, 0, sizeof(branch_head));
 	remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
 	if (!remote_head)
@@ -371,7 +376,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	if (!hashcmp(remote_head->sha1, branch_head)) {
 		strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
 			sha1_to_hex(branch_head), remote);
-		return;
+		goto cleanup;
 	}
 
 	/* See if remote matches <name>^^^.. or <name>~<number> */
@@ -411,7 +416,8 @@ static void merge_name(const char *remote, struct strbuf *msg)
 				    sha1_to_hex(remote_head->sha1),
 				    truname.buf + 11,
 				    (early ? " (early part)" : ""));
-			return;
+			strbuf_release(&truname);
+			goto cleanup;
 		}
 	}
 
@@ -432,10 +438,13 @@ static void merge_name(const char *remote, struct strbuf *msg)
 			strbuf_remove(&line, ptr-line.buf+1, 13);
 		strbuf_addbuf(msg, &line);
 		strbuf_release(&line);
-		return;
+		goto cleanup;
 	}
 	strbuf_addf(msg, "%s\t\tcommit '%s'\n",
 		sha1_to_hex(remote_head->sha1), remote);
+cleanup:
+	strbuf_release(&buf);
+	strbuf_release(&bname);
 }
 
 static int git_merge_config(const char *k, const char *v, void *cb)

t/t0100-previous.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+
+test_description='previous branch syntax @{-n}'
+
+. ./test-lib.sh
+
+test_expect_success 'branch -d @{-1}' '
+	test_commit A &&
+	git checkout -b junk &&
+	git checkout - &&
+	test "$(git symbolic-ref HEAD)" = refs/heads/master &&
+	git branch -d @{-1} &&
+	test_must_fail git rev-parse --verify refs/heads/junk
+'
+
+test_expect_success 'branch -d @{-12} when there is not enough switches yet' '
+	git reflog expire --expire=now &&
+	git checkout -b junk2 &&
+	git checkout - &&
+	test "$(git symbolic-ref HEAD)" = refs/heads/master &&
+	test_must_fail git branch -d @{-12} &&
+	git rev-parse --verify refs/heads/master
+'
+
+test_expect_success 'merge @{-1}' '
+	git checkout A &&
+	test_commit B &&
+	git checkout A &&
+	test_commit C &&
+	git branch -f master B &&
+	git branch -f other &&
+	git checkout other &&
+	git checkout master &&
+	git merge @{-1} &&
+	git cat-file commit HEAD | grep "Merge branch '\''other'\''"
+'
+
+test_expect_success 'merge @{-1} when there is not enough switches yet' '
+	git reflog expire --expire=now &&
+	git checkout -f master &&
+	git reset --hard B &&
+	git branch -f other C &&
+	git checkout other &&
+	git checkout master &&
+	test_must_fail git merge @{-12}
+'
+
+test_done
+