Merge pull request libgit2#5581 from libgit2/ethomson/mainbranch

Respect `init.defaultBranch` setting

Author: ethomson

src/clone.c

@@ -137,6 +137,31 @@ static int update_head_to_new_branch(
 	return error;
 }
 
+static int update_head_to_default(git_repository *repo)
+{
+	git_buf initialbranch = GIT_BUF_INIT;
+	const char *branch_name;
+	int error = 0;
+
+	if ((error = git_repository_initialbranch(&initialbranch, repo)) < 0)
+		goto done;
+
+	if (git__prefixcmp(initialbranch.ptr, GIT_REFS_HEADS_DIR) != 0) {
+		git_error_set(GIT_ERROR_INVALID, "invalid initial branch '%s'", initialbranch.ptr);
+		error = -1;
+		goto done;
+	}
+
+	branch_name = initialbranch.ptr + strlen(GIT_REFS_HEADS_DIR);
+
+	error = setup_tracking_config(repo, branch_name, GIT_REMOTE_ORIGIN,
+		initialbranch.ptr);
+
+done:
+	git_buf_dispose(&initialbranch);
+	return error;
+}
+
 static int update_head_to_remote(
 		git_repository *repo,
 		git_remote *remote,
@@ -147,16 +172,15 @@ static int update_head_to_remote(
 	git_refspec *refspec;
 	const git_remote_head *remote_head, **refs;
 	const git_oid *remote_head_id;
-	git_buf remote_master_name = GIT_BUF_INIT;
+	git_buf remote_branch_name = GIT_BUF_INIT;
 	git_buf branch = GIT_BUF_INIT;
 
 	if ((error = git_remote_ls(&refs, &refs_len, remote)) < 0)
 		return error;
 
 	/* We cloned an empty repository or one with an unborn HEAD */
 	if (refs_len == 0 || strcmp(refs[0]->name, GIT_HEAD_FILE))
-		return setup_tracking_config(
-			repo, "master", GIT_REMOTE_ORIGIN, GIT_REFS_HEADS_MASTER_FILE);
+		return update_head_to_default(repo);
 
 	/* We know we have HEAD, let's see where it points */
 	remote_head = refs[0];
@@ -179,9 +203,9 @@ static int update_head_to_remote(
 		goto cleanup;
 	}
 
-	/* Determine the remote tracking reference name from the local master */
+	/* Determine the remote tracking ref name from the local branch */
 	if ((error = git_refspec_transform(
-		&remote_master_name,
+		&remote_branch_name,
 		refspec,
 		git_buf_cstr(&branch))) < 0)
 		goto cleanup;
@@ -193,7 +217,7 @@ static int update_head_to_remote(
 		reflog_message);
 
 cleanup:
-	git_buf_dispose(&remote_master_name);
+	git_buf_dispose(&remote_branch_name);
 	git_buf_dispose(&branch);
 
 	return error;

src/refs.h

@@ -45,7 +45,6 @@ extern bool git_reference__enable_symbolic_ref_target_validation;
 #define GIT_REBASE_APPLY_DIR "rebase-apply/"
 #define GIT_REBASE_APPLY_REBASING_FILE GIT_REBASE_APPLY_DIR "rebasing"
 #define GIT_REBASE_APPLY_APPLYING_FILE GIT_REBASE_APPLY_DIR "applying"
-#define GIT_REFS_HEADS_MASTER_FILE GIT_REFS_HEADS_DIR "master"
 
 #define GIT_SEQUENCER_DIR "sequencer/"
 #define GIT_SEQUENCER_HEAD_FILE GIT_SEQUENCER_DIR "head"

src/remote.c

@@ -2375,29 +2375,36 @@ int git_remote_default_branch(git_buf *out, git_remote *remote)
 	const git_remote_head *guess = NULL;
 	const git_oid *head_id;
 	size_t heads_len, i;
+	git_buf local_default = GIT_BUF_INIT;
 	int error;
 
 	assert(out);
 
 	if ((error = git_remote_ls(&heads, &heads_len, remote)) < 0)
-		return error;
-
-	if (heads_len == 0)
-		return GIT_ENOTFOUND;
+		goto done;
 
-	if (strcmp(heads[0]->name, GIT_HEAD_FILE))
-		return GIT_ENOTFOUND;
+	if (heads_len == 0 || strcmp(heads[0]->name, GIT_HEAD_FILE)) {
+		error = GIT_ENOTFOUND;
+		goto done;
+	}
 
 	git_buf_sanitize(out);
+
 	/* the first one must be HEAD so if that has the symref info, we're done */
-	if (heads[0]->symref_target)
-		return git_buf_puts(out, heads[0]->symref_target);
+	if (heads[0]->symref_target) {
+		error = git_buf_puts(out, heads[0]->symref_target);
+		goto done;
+	}
 
 	/*
 	 * If there's no symref information, we have to look over them
-	 * and guess. We return the first match unless the master
-	 * branch is a candidate. Then we return the master branch.
+	 * and guess. We return the first match unless the default
+	 * branch is a candidate. Then we return the default branch.
 	 */
+
+	if ((error = git_repository_initialbranch(&local_default, remote->repo)) < 0)
+		goto done;
+
 	head_id = &heads[0]->oid;
 
 	for (i = 1; i < heads_len; i++) {
@@ -2412,16 +2419,22 @@ int git_remote_default_branch(git_buf *out, git_remote *remote)
 			continue;
 		}
 
-		if (!git__strcmp(GIT_REFS_HEADS_MASTER_FILE, heads[i]->name)) {
+		if (!git__strcmp(local_default.ptr, heads[i]->name)) {
 			guess = heads[i];
 			break;
 		}
 	}
 
-	if (!guess)
-		return GIT_ENOTFOUND;
+	if (!guess) {
+		error = GIT_ENOTFOUND;
+		goto done;
+	}
+
+	error = git_buf_puts(out, guess->name);
 
-	return git_buf_puts(out, guess->name);
+done:
+	git_buf_dispose(&local_default);
+	return error;
 }
 
 int git_remote_upload(git_remote *remote, const git_strarray *refspecs, const git_push_options *opts)

src/repository.c

@@ -70,7 +70,7 @@ static int check_extensions(git_config *config, int version);
 
 #define GIT_FILE_CONTENT_PREFIX "gitdir:"
 
-#define GIT_BRANCH_MASTER "master"
+#define GIT_BRANCH_DEFAULT "master"
 
 #define GIT_REPO_VERSION 0
 #define GIT_REPO_MAX_VERSION 1
@@ -1408,9 +1408,6 @@ int git_repository_create_head(const char *git_dir, const char *ref_name)
 	    (error = git_filebuf_open(&ref, ref_path.ptr, 0, GIT_REFS_FILE_MODE)) < 0)
 		goto out;
 
-	if (!ref_name)
-		ref_name = GIT_BRANCH_MASTER;
-
 	if (git__prefixcmp(ref_name, GIT_REFS_DIR) == 0)
 		fmt = "ref: %s\n";
 	else
@@ -2061,6 +2058,43 @@ static int repo_init_directories(
 	return error;
 }
 
+static int repo_init_head(const char *repo_dir, const char *given)
+{
+	git_config *cfg = NULL;
+	git_buf head_path = GIT_BUF_INIT, cfg_branch = GIT_BUF_INIT;
+	const char *initial_head = NULL;
+	int error;
+
+	if ((error = git_buf_joinpath(&head_path, repo_dir, GIT_HEAD_FILE)) < 0)
+		goto out;
+
+	/*
+	 * A template may have set a HEAD; use that unless it's been
+	 * overridden by the caller's given initial head setting.
+	 */
+	if (git_path_exists(head_path.ptr) && !given)
+		goto out;
+
+	if (given) {
+		initial_head = given;
+	} else if ((error = git_config_open_default(&cfg)) >= 0 &&
+	           (error = git_config_get_string_buf(&cfg_branch, cfg, "init.defaultbranch")) >= 0) {
+		initial_head = cfg_branch.ptr;
+	}
+
+	if (!initial_head)
+		initial_head = GIT_BRANCH_DEFAULT;
+
+	error = git_repository_create_head(repo_dir, initial_head);
+
+out:
+	git_config_free(cfg);
+	git_buf_dispose(&head_path);
+	git_buf_dispose(&cfg_branch);
+
+	return error;
+}
+
 static int repo_init_create_origin(git_repository *repo, const char *url)
 {
 	int error;
@@ -2091,7 +2125,7 @@ int git_repository_init_ext(
 	git_repository_init_options *opts)
 {
 	git_buf repo_path = GIT_BUF_INIT, wd_path = GIT_BUF_INIT,
-		common_path = GIT_BUF_INIT, head_path = GIT_BUF_INIT;
+		common_path = GIT_BUF_INIT;
 	const char *wd;
 	bool is_valid;
 	int error;
@@ -2125,16 +2159,7 @@ int git_repository_init_ext(
 	} else {
 		if ((error = repo_init_structure(repo_path.ptr, wd, opts)) < 0 ||
 		    (error = repo_init_config(repo_path.ptr, wd, opts->flags, opts->mode)) < 0 ||
-		    (error = git_buf_joinpath(&head_path, repo_path.ptr, GIT_HEAD_FILE)) < 0)
-			goto out;
-
-		/*
-		 * Only set the new HEAD if the file does not exist already via
-		 * a template or if the caller has explicitly supplied an
-		 * initial HEAD value.
-		 */
-		if ((!git_path_exists(head_path.ptr) || opts->initial_head) &&
-		    (error = git_repository_create_head(repo_path.ptr, opts->initial_head)) < 0)
+		    (error = repo_init_head(repo_path.ptr, opts->initial_head)) < 0)
 			goto out;
 	}
 
@@ -2146,7 +2171,6 @@ int git_repository_init_ext(
 		goto out;
 
 out:
-	git_buf_dispose(&head_path);
 	git_buf_dispose(&common_path);
 	git_buf_dispose(&repo_path);
 	git_buf_dispose(&wd_path);
@@ -2330,23 +2354,59 @@ static int repo_contains_no_reference(git_repository *repo)
 	return error;
 }
 
+int git_repository_initialbranch(git_buf *out, git_repository *repo)
+{
+	git_config *config;
+	git_config_entry *entry = NULL;
+	const char *branch;
+	int error;
+
+	if ((error = git_repository_config__weakptr(&config, repo)) < 0)
+		return error;
+
+	if ((error = git_config_get_entry(&entry, config, "init.defaultbranch")) == 0) {
+		branch = entry->value;
+	}
+	else if (error == GIT_ENOTFOUND) {
+		branch = GIT_BRANCH_DEFAULT;
+	}
+	else {
+		goto done;
+	}
+
+	if ((error = git_buf_puts(out, GIT_REFS_HEADS_DIR)) < 0 ||
+	    (error = git_buf_puts(out, branch)) < 0)
+	    goto done;
+
+	if (!git_reference_is_valid_name(out->ptr)) {
+		git_error_set(GIT_ERROR_INVALID, "the value of init.defaultBranch is not a valid reference name");
+		error = -1;
+	}
+
+done:
+	git_config_entry_free(entry);
+	return error;
+}
+
 int git_repository_is_empty(git_repository *repo)
 {
 	git_reference *head = NULL;
-	int is_empty = 0;
+	git_buf initialbranch = GIT_BUF_INIT;
+	int result = 0;
 
-	if (git_reference_lookup(&head, repo, GIT_HEAD_FILE) < 0)
-		return -1;
+	if ((result = git_reference_lookup(&head, repo, GIT_HEAD_FILE)) < 0 ||
+	    (result = git_repository_initialbranch(&initialbranch, repo)) < 0)
+		goto done;
 
-	if (git_reference_type(head) == GIT_REFERENCE_SYMBOLIC)
-		is_empty =
-			(strcmp(git_reference_symbolic_target(head),
-					GIT_REFS_HEADS_DIR "master") == 0) &&
-			repo_contains_no_reference(repo);
+	result = (git_reference_type(head) == GIT_REFERENCE_SYMBOLIC &&
+	          strcmp(git_reference_symbolic_target(head), initialbranch.ptr) == 0 &&
+	          repo_contains_no_reference(repo));
 
+done:
 	git_reference_free(head);
+	git_buf_dispose(&initialbranch);
 
-	return is_empty;
+	return result;
 }
 
 static const char *resolved_parent_path(const git_repository *repo, git_repository_item_t item, git_repository_item_t fallback)

src/repository.h

@@ -232,4 +232,10 @@ extern size_t git_repository__reserved_names_posix_len;
 bool git_repository__reserved_names(
 	git_buf **out, size_t *outlen, git_repository *repo, bool include_ntfs);
 
+/*
+ * The default branch for the repository; the `init.defaultBranch`
+ * configuration option, if set, or `master` if it is not.
+ */
+int git_repository_initialbranch(git_buf *out, git_repository *repo);
+
 #endif

tests/clone/empty.c

@@ -2,6 +2,7 @@
 
 #include "git2/clone.h"
 #include "repository.h"
+#include "repo/repo_helpers.h"
 
 static git_clone_options g_options;
 static git_repository *g_repo;
@@ -22,6 +23,7 @@ void test_clone_empty__initialize(void)
 
 void test_clone_empty__cleanup(void)
 {
+	cl_fixture_cleanup("tmp_global_path");
 	cl_git_sandbox_cleanup();
 }
 
@@ -66,6 +68,21 @@ void test_clone_empty__can_clone_an_empty_local_repo_barely(void)
 		expected_tracked_branch_name));
 }
 
+void test_clone_empty__respects_initialbranch_config(void)
+{
+	git_buf buf = GIT_BUF_INIT;
+
+	create_tmp_global_config("tmp_global_path", "init.defaultbranch", "my_default_branch");
+
+	cl_set_cleanup(&cleanup_repository, "./empty");
+
+	g_options.bare = true;
+	cl_git_pass(git_clone(&g_repo_cloned, "./empty_bare.git", "./empty", &g_options));
+	cl_git_pass(git_branch_upstream_name(&buf, g_repo_cloned, "refs/heads/my_default_branch"));
+	cl_assert_equal_s("refs/remotes/origin/my_default_branch", buf.ptr);
+	git_buf_dispose(&buf);
+}
+
 void test_clone_empty__can_clone_an_empty_local_repo(void)
 {
 	cl_set_cleanup(&cleanup_repository, "./empty");

tests/repo/init.c

@@ -665,3 +665,19 @@ void test_repo_init__unwriteable_directory(void)
 	clar__skip();
 #endif
 }
+
+void test_repo_init__defaultbranch_config(void)
+{
+	git_reference *head;
+
+	cl_set_cleanup(&cleanup_repository, "repo");
+
+	create_tmp_global_config("tmp_global_path", "init.defaultbranch", "my_default_branch");
+
+	cl_git_pass(git_repository_init(&_repo, "repo", 0));
+	cl_git_pass(git_reference_lookup(&head, _repo, "HEAD"));
+
+	cl_assert_equal_s("refs/heads/my_default_branch", git_reference_symbolic_target(head));
+
+	git_reference_free(head);
+}