Merge branch 'js/default-branch-name' into seen

The name of the primary branch in existing repositories, and the
default name used for the first branch in newly created
repositories, is made configurable, so that we can eventually wean
ourselves off of the hardcoded 'master'.

* js/default-branch-name:
  testsvn: respect `init.defaultBranch`
  remote: use the configured default branch name when appropriate
  clone: use configured default branch name when appropriate
  init: allow setting the default for the initial branch name via the config
  init: allow specifying the initial branch name for the new repository
  submodule: use a better fall-back for missing remote.<name>.branch
  send-pack/transport-helper: avoid mentioning a particular branch
  fmt-merge-msg: stop treating `master` specially

Author: gitster

Documentation/config/init.txt

@@ -1,3 +1,7 @@
 init.templateDir::
 	Specify the directory from which templates will be copied.
 	(See the "TEMPLATE DIRECTORY" section of linkgit:git-init[1].)
+
+init.defaultBranch::
+	Allows overriding the default branch name e.g. when initializing
+	a new repository or when cloning an empty repository.

Documentation/git-init.txt

@@ -11,6 +11,7 @@ SYNOPSIS
 [verse]
 'git init' [-q | --quiet] [--bare] [--template=<template_directory>]
 	  [--separate-git-dir <git dir>] [--object-format=<format]
+	  [-b <branch-name> | --initial-branch=<branch-name>]
 	  [--shared[=<permissions>]] [directory]
 
 
@@ -67,6 +68,12 @@ repository.
 +
 If this is reinitialization, the repository will be moved to the specified path.
 
+-b <branch-name::
+--initial-branch=<branch-name>::
+
+Use the specified name for the initial branch in the newly created repository.
+If not specified, fall back to the default name: `master`.
+
 --shared[=(false|true|umask|group|all|world|everybody|0xxx)]::
 
 Specify that the Git repository is to be shared amongst several users.  This

Documentation/git-submodule.txt

@@ -284,7 +284,7 @@ OPTIONS
 	`.gitmodules` for `update --remote`.  A special value of `.` is used to
 	indicate that the name of the branch in the submodule should be the
 	same name as the current branch in the current repository.  If the
-	option is not specified, it defaults to 'master'.
+	option is not specified, it defaults to 'HEAD'.
 
 -f::
 --force::
@@ -322,7 +322,7 @@ OPTIONS
 	the superproject's recorded SHA-1 to update the submodule, use the
 	status of the submodule's remote-tracking branch.  The remote used
 	is branch's remote (`branch.<name>.remote`), defaulting to `origin`.
-	The remote branch used defaults to `master`, but the branch name may
+	The remote branch used defaults to `HEAD`, but the branch name may
 	be overridden by setting the `submodule.<name>.branch` option in
 	either `.gitmodules` or `.git/config` (with `.git/config` taking
 	precedence).

builtin/clone.c

@@ -1111,7 +1111,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		}
 	}
 
-	init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, INIT_DB_QUIET);
+	init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, NULL,
+		INIT_DB_QUIET);
 
 	if (real_git_dir)
 		git_dir = real_git_dir;
@@ -1275,9 +1276,13 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		remote_head_points_at = NULL;
 		remote_head = NULL;
 		option_no_checkout = 1;
-		if (!option_bare)
-			install_branch_config(0, "master", option_origin,
-					      "refs/heads/master");
+		if (!option_bare) {
+			const char *branch = git_default_branch_name();
+			char *ref = xstrfmt("refs/heads/%s", branch);
+
+			install_branch_config(0, branch, option_origin, ref);
+			free(ref);
+		}
 	}
 
 	write_refspec_config(src_ref_prefix, our_head_points_at,

builtin/init-db.c

@@ -203,6 +203,7 @@ void initialize_repository_version(int hash_algo)
 
 static int create_default_files(const char *template_path,
 				const char *original_git_dir,
+				const char *initial_branch,
 				const struct repository_format *fmt)
 {
 	struct stat st1;
@@ -258,16 +259,29 @@ static int create_default_files(const char *template_path,
 		die("failed to set up refs db: %s", err.buf);
 
 	/*
-	 * Create the default symlink from ".git/HEAD" to the "master"
-	 * branch, if it does not exist yet.
+	 * Create the default symlink from ".git/HEAD" to the default
+	 * branch name, if it does not exist yet.
 	 */
 	path = git_path_buf(&buf, "HEAD");
 	reinit = (!access(path, R_OK)
 		  || readlink(path, junk, sizeof(junk)-1) != -1);
 	if (!reinit) {
-		if (create_symref("HEAD", "refs/heads/master", NULL) < 0)
+		char *ref;
+
+		if (!initial_branch)
+			initial_branch = git_default_branch_name();
+
+		ref = xstrfmt("refs/heads/%s", initial_branch);
+		if (check_refname_format(ref, 0) < 0)
+			die(_("invalid initial branch name: '%s'"),
+			    initial_branch);
+
+		if (create_symref("HEAD", ref, NULL) < 0)
 			exit(1);
-	}
+		free(ref);
+	} else if (initial_branch)
+		warning(_("re-init: ignoring --initial-branch=%s"),
+			initial_branch);
 
 	initialize_repository_version(fmt->hash_algo);
 
@@ -383,7 +397,8 @@ static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash
 }
 
 int init_db(const char *git_dir, const char *real_git_dir,
-	    const char *template_dir, int hash, unsigned int flags)
+	    const char *template_dir, int hash, const char *initial_branch,
+	    unsigned int flags)
 {
 	int reinit;
 	int exist_ok = flags & INIT_DB_EXIST_OK;
@@ -425,7 +440,8 @@ int init_db(const char *git_dir, const char *real_git_dir,
 
 	validate_hash_algorithm(&repo_fmt, hash);
 
-	reinit = create_default_files(template_dir, original_git_dir, &repo_fmt);
+	reinit = create_default_files(template_dir, original_git_dir,
+				      initial_branch, &repo_fmt);
 
 	create_object_directory();
 
@@ -528,6 +544,7 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 	const char *template_dir = NULL;
 	unsigned int flags = 0;
 	const char *object_format = NULL;
+	const char *initial_branch = NULL;
 	int hash_algo = GIT_HASH_UNKNOWN;
 	const struct option init_db_options[] = {
 		OPT_STRING(0, "template", &template_dir, N_("template-directory"),
@@ -541,6 +558,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 		OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
 		OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
 			   N_("separate git dir from working tree")),
+		OPT_STRING('b', "initial-branch", &initial_branch, N_("name"),
+			   N_("override the name of the initial branch")),
 		OPT_STRING(0, "object-format", &object_format, N_("hash"),
 			   N_("specify the hash algorithm to use")),
 		OPT_END()
@@ -652,5 +671,6 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 	UNLEAK(work_tree);
 
 	flags |= INIT_DB_EXIST_OK;
-	return init_db(git_dir, real_git_dir, template_dir, hash_algo, flags);
+	return init_db(git_dir, real_git_dir, template_dir, hash_algo,
+		       initial_branch, flags);
 }

builtin/submodule--helper.c

@@ -1981,7 +1981,7 @@ static const char *remote_submodule_branch(const char *path)
 	free(key);
 
 	if (!branch)
-		return "master";
+		return "HEAD";
 
 	if (!strcmp(branch, ".")) {
 		const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, NULL);

cache.h

@@ -628,7 +628,7 @@ int path_inside_repo(const char *prefix, const char *path);
 
 int init_db(const char *git_dir, const char *real_git_dir,
 	    const char *template_dir, int hash_algo,
-	    unsigned int flags);
+	    const char *initial_branch, unsigned int flags);
 void initialize_repository_version(int hash_algo);
 
 void sanitize_stdfds(void);

fmt-merge-msg.c

@@ -451,10 +451,7 @@ static void fmt_merge_msg_title(struct strbuf *out,
 			strbuf_addf(out, " of %s", srcs.items[i].string);
 	}
 
-	if (!strcmp("master", current_branch))
-		strbuf_addch(out, '\n');
-	else
-		strbuf_addf(out, " into %s\n", current_branch);
+	strbuf_addf(out, " into %s\n", current_branch);
 }
 
 static void fmt_tag_signature(struct strbuf *tagbuf,

refs.c

@@ -562,6 +562,36 @@ void expand_ref_prefix(struct argv_array *prefixes, const char *prefix)
 		argv_array_pushf(prefixes, *p, len, prefix);
 }
 
+char *repo_default_branch_name(struct repository *r)
+{
+	const char *config_key = "init.defaultbranch";
+	const char *config_display_key = "init.defaultBranch";
+	char *ret = NULL, *full_ref;
+
+	if (repo_config_get_string(r, config_key, &ret) < 0)
+		die(_("could not retrieve `%s`"), config_display_key);
+
+	if (!ret)
+		ret = xstrdup("master");
+
+	full_ref = xstrfmt("refs/heads/%s", ret);
+	if (check_refname_format(full_ref, 0))
+		die(_("invalid branch name: %s = %s"), config_display_key, ret);
+	free(full_ref);
+
+	return ret;
+}
+
+const char *git_default_branch_name(void)
+{
+	static char *ret;
+
+	if (!ret)
+		ret = repo_default_branch_name(the_repository);
+
+	return ret;
+}
+
 /*
  * *string and *len will only be substituted, and *string returned (for
  * later free()ing) if the string passed in is a magic short-hand form

refs.h

@@ -154,6 +154,15 @@ int repo_dwim_log(struct repository *r, const char *str, int len, struct object_
 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_log(const char *str, int len, struct object_id *oid, char **ref);
 
+/*
+ * Retrieves the default branch name for newly-initialized repositories.
+ *
+ * The return value of `repo_default_branch_name()` is an allocated string. The
+ * return value of `git_default_branch_name()` is a singleton.
+ */
+const char *git_default_branch_name(void);
+char *repo_default_branch_name(struct repository *r);
+
 /*
  * A ref_transaction represents a collection of reference updates that
  * should succeed or fail together.

remote-testsvn.c

@@ -13,7 +13,7 @@
 static const char *url;
 static int dump_from_file;
 static const char *private_ref;
-static const char *remote_ref = "refs/heads/master";
+static char *remote_ref;
 static const char *marksfilename, *notes_ref;
 struct rev_note { unsigned int rev_nr; };
 
@@ -286,14 +286,17 @@ int cmd_main(int argc, const char **argv)
 			private_ref_sb = STRBUF_INIT, marksfilename_sb = STRBUF_INIT,
 			notes_ref_sb = STRBUF_INIT;
 	static struct remote *remote;
-	const char *url_in;
+	const char *url_in, *remote_ref_short;
 
 	setup_git_directory();
 	if (argc < 2 || argc > 3) {
 		usage("git-remote-svn <remote-name> [<url>]");
 		return 1;
 	}
 
+	remote_ref_short = git_default_branch_name();
+	remote_ref = xstrfmt("refs/heads/%s", remote_ref_short);
+
 	remote = remote_get(argv[1]);
 	url_in = (argc == 3) ? argv[2] : remote->url[0];
 
@@ -306,7 +309,8 @@ int cmd_main(int argc, const char **argv)
 		url = url_sb.buf;
 	}
 
-	strbuf_addf(&private_ref_sb, "refs/svn/%s/master", remote->name);
+	strbuf_addf(&private_ref_sb, "refs/svn/%s/%s",
+		    remote->name, remote_ref_short);
 	private_ref = private_ref_sb.buf;
 
 	strbuf_addf(&notes_ref_sb, "refs/notes/%s/revs", remote->name);

remote.c

@@ -276,15 +276,15 @@ static void read_branches_file(struct remote *remote)
 
 	/*
 	 * The branches file would have URL and optionally
-	 * #branch specified.  The "master" (or specified) branch is
+	 * #branch specified.  The main (or specified) branch is
 	 * fetched and stored in the local branch matching the
 	 * remote name.
 	 */
 	frag = strchr(buf.buf, '#');
 	if (frag)
 		*(frag++) = '\0';
 	else
-		frag = "master";
+		frag = (char *)git_default_branch_name();
 
 	add_url_alias(remote, strbuf_detach(&buf, NULL));
 	strbuf_addf(&buf, "refs/heads/%s:refs/heads/%s",
@@ -2147,8 +2147,16 @@ struct ref *guess_remote_head(const struct ref *head,
 	if (head->symref)
 		return copy_ref(find_ref_by_name(refs, head->symref));
 
-	/* If refs/heads/master could be right, it is. */
+	/* If a remote branch exists with the default branch name, let's use it. */
 	if (!all) {
+		char *ref = xstrfmt("refs/heads/%s", git_default_branch_name());
+
+		r = find_ref_by_name(refs, ref);
+		free(ref);
+		if (r && oideq(&r->old_oid, &head->old_oid))
+			return copy_ref(r);
+
+		/* Fall back to the hard-coded historical default */
 		r = find_ref_by_name(refs, "refs/heads/master");
 		if (r && oideq(&r->old_oid, &head->old_oid))
 			return copy_ref(r);

send-pack.c

@@ -471,7 +471,7 @@ int send_pack(struct send_pack_args *args,
 
 	if (!remote_refs) {
 		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
-			"Perhaps you should specify a branch such as 'master'.\n");
+			"Perhaps you should specify a specific branch.\n");
 		return 0;
 	}
 	if (args->atomic && !atomic_supported)

t/t0001-init.sh

@@ -464,4 +464,30 @@ test_expect_success MINGW 'redirect std handles' '
 	grep "Needed a single revision" output.txt
 '
 
+test_expect_success '--initial-branch' '
+	git init --initial-branch=hello initial-branch-option &&
+	git -C initial-branch-option symbolic-ref HEAD >actual &&
+	echo refs/heads/hello >expect &&
+	test_cmp expect actual &&
+
+	: re-initializing should not change the branch name &&
+	git init --initial-branch=ignore initial-branch-option 2>err &&
+	test_i18ngrep "ignoring --initial-branch" err &&
+	git -C initial-branch-option symbolic-ref HEAD >actual &&
+	grep hello actual
+'
+
+test_expect_success 'overridden default initial branch name (config)' '
+	test_config_global init.defaultBranch nmb &&
+	git init initial-branch-config &&
+	git -C initial-branch-config symbolic-ref HEAD >actual &&
+	grep nmb actual
+'
+
+test_expect_success 'invalid default branch name' '
+	test_config_global init.defaultBranch "with space" &&
+	test_must_fail git init initial-branch-invalid 2>err &&
+	test_i18ngrep "invalid branch name" err
+'
+
 test_done

t/t1507-rev-parse-upstream.sh

@@ -137,7 +137,7 @@ test_expect_success 'merge my-side@{u} records the correct name' '
 	git branch -t new my-side@{u} &&
 	git merge -s ours new@{u} &&
 	git show -s --pretty=tformat:%s >actual &&
-	echo "Merge remote-tracking branch ${SQ}origin/side${SQ}" >expect &&
+	echo "Merge remote-tracking branch ${SQ}origin/side${SQ} into master" >expect &&
 	test_cmp expect actual
 )
 '

t/t4013-diff-various.sh

@@ -117,12 +117,12 @@ test_expect_success setup '
 
 : <<\EOF
 ! [initial] Initial
- * [master] Merge branch 'side'
+ * [master] Merge branch 'side' into master
   ! [rearrange] Rearranged lines in dir/sub
    ! [side] Side
 ----
   +  [rearrange] Rearranged lines in dir/sub
- -   [master] Merge branch 'side'
+ -   [master] Merge branch 'side' into master
  * + [side] Side
  *   [master^] Third
  *   [master~2] Second

t/t4013/diff.log_--decorate=full_--all

@@ -31,7 +31,7 @@ Merge: 9a6d494 c7a2ab9
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:04:00 2006 +0000
 
-    Merge branch 'side'
+    Merge branch 'side' into master
 
 commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (refs/heads/side)
 Author: A U Thor <author@example.com>

t/t4013/diff.log_--decorate_--all

@@ -31,7 +31,7 @@ Merge: 9a6d494 c7a2ab9
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:04:00 2006 +0000
 
-    Merge branch 'side'
+    Merge branch 'side' into master
 
 commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (side)
 Author: A U Thor <author@example.com>