3 files changed, 216 insertions, 40 deletions
diff --git a/Documentation/config/init.txt b/Documentation/config/init.txt
index af03acdbcb..e45b2a8121 100644
--- a/Documentation/config/init.txt
+++ b/Documentation/config/init.txt
@@ -8,3 +8,13 @@ endif::[]
 `init.defaultBranch`::
 	Allows overriding the default branch name e.g. when initializing
 	a new repository.
+`init.defaultObjectFormat`::
+	Allows overriding the default object format for new repositories. See
+	`--object-format=` in linkgit:git-init[1]. Both the command line option
+	and the `GIT_DEFAULT_HASH` environment variable take precedence over
+	this config.
+`init.defaultRefFormat`::
+	Allows overriding the default ref storage format for new repositories.
+	See `--ref-format=` in linkgit:git-init[1]. Both the command line
+	option and the `GIT_DEFAULT_REF_FORMAT` environment variable take
+	precedence over this config.
diff --git a/setup.c b/setup.c
index 5f81d9fac0..2e11542a1f 100644
--- a/setup.c
+++ b/setup.c
@@ -2320,14 +2320,67 @@ static void separate_git_dir(const char *git_dir, const char *git_link)
 	write_file(git_link, "gitdir: %s", git_dir);
 }
 
-static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash)
+struct default_format_config {
+	int hash;
+	enum ref_storage_format ref_format;
+};
+
+static int read_default_format_config(const char *key, const char *value,
+				      const struct config_context *ctx UNUSED,
+				      void *payload)
 {
-	const char *env = getenv(GIT_DEFAULT_HASH_ENVIRONMENT);
+	struct default_format_config *cfg = payload;
+	char *str = NULL;
+	int ret;
+
+	if (!strcmp(key, "init.defaultobjectformat")) {
+		ret = git_config_string(&str, key, value);
+		if (ret)
+			goto out;
+		cfg->hash = hash_algo_by_name(str);
+		if (cfg->hash == GIT_HASH_UNKNOWN)
+			warning(_("unknown hash algorithm '%s'"), str);
+		goto out;
+	}
+
+	if (!strcmp(key, "init.defaultrefformat")) {
+		ret = git_config_string(&str, key, value);
+		if (ret)
+			goto out;
+		cfg->ref_format = ref_storage_format_by_name(str);
+		if (cfg->ref_format == REF_STORAGE_FORMAT_UNKNOWN)
+			warning(_("unknown ref storage format '%s'"), str);
+		goto out;
+	}
+
+	ret = 0;
+out:
+	free(str);
+	return ret;
+}
+
+static void repository_format_configure(struct repository_format *repo_fmt,
+					int hash, enum ref_storage_format ref_format)
+{
+	struct default_format_config cfg = {
+		.hash = GIT_HASH_UNKNOWN,
+		.ref_format = REF_STORAGE_FORMAT_UNKNOWN,
+	};
+	struct config_options opts = {
+		.respect_includes = 1,
+		.ignore_repo = 1,
+		.ignore_worktree = 1,
+	};
+	const char *env;
+
+	config_with_options(read_default_format_config, &cfg, NULL, NULL, &opts);
+
 	/*
 	 * If we already have an initialized repo, don't allow the user to
 	 * specify a different algorithm, as that could cause corruption.
 	 * Otherwise, if the user has specified one on the command line, use it.
 	 */
+	env = getenv(GIT_DEFAULT_HASH_ENVIRONMENT);
 	if (repo_fmt->version >= 0 && hash != GIT_HASH_UNKNOWN && hash != repo_fmt->hash_algo)
 		die(_("attempt to reinitialize repository with different hash"));
 	else if (hash != GIT_HASH_UNKNOWN)
@@ -2337,26 +2390,27 @@ static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash
 		if (env_algo == GIT_HASH_UNKNOWN)
 			die(_("unknown hash algorithm '%s'"), env);
 		repo_fmt->hash_algo = env_algo;
+	} else if (cfg.hash != GIT_HASH_UNKNOWN) {
+		repo_fmt->hash_algo = cfg.hash;
 	}
-}
-
-static void validate_ref_storage_format(struct repository_format *repo_fmt,
-					enum ref_storage_format format)
-{
-	const char *name = getenv("GIT_DEFAULT_REF_FORMAT");
+	repo_set_hash_algo(the_repository, repo_fmt->hash_algo);
 
+	env = getenv("GIT_DEFAULT_REF_FORMAT");
 	if (repo_fmt->version >= 0 &&
-	    format != REF_STORAGE_FORMAT_UNKNOWN &&
-	    format != repo_fmt->ref_storage_format) {
+	    ref_format != REF_STORAGE_FORMAT_UNKNOWN &&
+	    ref_format != repo_fmt->ref_storage_format) {
 		die(_("attempt to reinitialize repository with different reference storage format"));
-	} else if (format != REF_STORAGE_FORMAT_UNKNOWN) {
-		repo_fmt->ref_storage_format = format;
-	} else if (name) {
-		format = ref_storage_format_by_name(name);
-		if (format == REF_STORAGE_FORMAT_UNKNOWN)
-			die(_("unknown ref storage format '%s'"), name);
-		repo_fmt->ref_storage_format = format;
+	} else if (ref_format != REF_STORAGE_FORMAT_UNKNOWN) {
+		repo_fmt->ref_storage_format = ref_format;
+	} else if (env) {
+		ref_format = ref_storage_format_by_name(env);
+		if (ref_format == REF_STORAGE_FORMAT_UNKNOWN)
+			die(_("unknown ref storage format '%s'"), env);
+		repo_fmt->ref_storage_format = ref_format;
+	} else if (cfg.ref_format != REF_STORAGE_FORMAT_UNKNOWN) {
+		repo_fmt->ref_storage_format = cfg.ref_format;
 	}
+	repo_set_ref_storage_format(the_repository, repo_fmt->ref_storage_format);
 }
 
 int init_db(const char *git_dir, const char *real_git_dir,
@@ -2389,22 +2443,15 @@ int init_db(const char *git_dir, const char *real_git_dir,
 	}
 	startup_info->have_repository = 1;
 
-	/* Check to see if the repository version is right.
+	/*
+	 * Check to see if the repository version is right.
 	 * Note that a newly created repository does not have
 	 * config file, so this will not fail.  What we are catching
 	 * is an attempt to reinitialize new repository with an old tool.
 	 */
 	check_repository_format(&repo_fmt);
 
-	validate_hash_algorithm(&repo_fmt, hash);
-	validate_ref_storage_format(&repo_fmt, ref_storage_format);
-
-	/*
-	 * Now that we have set up both the hash algorithm and the ref storage
-	 * format we can update the repository's settings accordingly.
-	 */
-	repo_set_hash_algo(the_repository, repo_fmt.hash_algo);
-	repo_set_ref_storage_format(the_repository, repo_fmt.ref_storage_format);
+	repository_format_configure(&repo_fmt, hash, ref_storage_format);
 
 	/*
 	 * Ensure `core.hidedotfiles` is processed. This must happen after we
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 49e9bf77c6..0178aa62a4 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -500,6 +500,7 @@ test_expect_success 're-init from a linked worktree' '
 '
 
 test_expect_success 'init honors GIT_DEFAULT_HASH' '
+	test_when_finished "rm -rf sha1 sha256" &&
 	GIT_DEFAULT_HASH=sha1 git init sha1 &&
 	git -C sha1 rev-parse --show-object-format >actual &&
 	echo sha1 >expected &&
@@ -511,6 +512,7 @@ test_expect_success 'init honors GIT_DEFAULT_HASH' '
 '
 
 test_expect_success 'init honors --object-format' '
+	test_when_finished "rm -rf explicit-sha1 explicit-sha256" &&
 	git init --object-format=sha1 explicit-sha1 &&
 	git -C explicit-sha1 rev-parse --show-object-format >actual &&
 	echo sha1 >expected &&
@@ -521,7 +523,58 @@ test_expect_success 'init honors --object-format' '
 	test_cmp expected actual
 '
 
+test_expect_success 'init honors init.defaultObjectFormat' '
+	test_when_finished "rm -rf sha1 sha256" &&
+
+	test_config_global init.defaultObjectFormat sha1 &&
+	(
+		sane_unset GIT_DEFAULT_HASH &&
+		git init sha1 &&
+		git -C sha1 rev-parse --show-object-format >actual &&
+		echo sha1 >expected &&
+		test_cmp expected actual
+	) &&
+
+	test_config_global init.defaultObjectFormat sha256 &&
+	(
+		sane_unset GIT_DEFAULT_HASH &&
+		git init sha256 &&
+		git -C sha256 rev-parse --show-object-format >actual &&
+		echo sha256 >expected &&
+		test_cmp expected actual
+	)
+'
+
+test_expect_success 'init warns about invalid init.defaultObjectFormat' '
+	test_when_finished "rm -rf repo" &&
+	test_config_global init.defaultObjectFormat garbage &&
+
+	echo "warning: unknown hash algorithm ${SQ}garbage${SQ}" >expect &&
+	git init repo 2>err &&
+	test_cmp expect err &&
+
+	git -C repo rev-parse --show-object-format >actual &&
+	echo $GIT_DEFAULT_HASH >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success '--object-format overrides GIT_DEFAULT_HASH' '
+	test_when_finished "rm -rf repo" &&
+	GIT_DEFAULT_HASH=sha1 git init --object-format=sha256 repo &&
+	git -C repo rev-parse --show-object-format >actual &&
+	echo sha256 >expected
+'
+
+test_expect_success 'GIT_DEFAULT_HASH overrides init.defaultObjectFormat' '
+	test_when_finished "rm -rf repo" &&
+	test_config_global init.defaultObjectFormat sha1 &&
+	GIT_DEFAULT_HASH=sha256 git init repo &&
+	git -C repo rev-parse --show-object-format >actual &&
+	echo sha256 >expected
+'
+
 test_expect_success 'extensions.objectFormat is not allowed with repo version 0' '
+	test_when_finished "rm -rf explicit-v0" &&
 	git init --object-format=sha256 explicit-v0 &&
 	git -C explicit-v0 config core.repositoryformatversion 0 &&
 	test_must_fail git -C explicit-v0 rev-parse --show-object-format
@@ -558,15 +611,6 @@ test_expect_success DEFAULT_REPO_FORMAT 'extensions.refStorage with unknown back
 	grep "invalid value for ${SQ}extensions.refstorage${SQ}: ${SQ}garbage${SQ}" err
 '
 
-test_expect_success DEFAULT_REPO_FORMAT 'init with GIT_DEFAULT_REF_FORMAT=files' '
-	test_when_finished "rm -rf refformat" &&
-	GIT_DEFAULT_REF_FORMAT=files git init refformat &&
-	echo 0 >expect &&
-	git -C refformat config core.repositoryformatversion >actual &&
-	test_cmp expect actual &&
-	test_must_fail git -C refformat config extensions.refstorage
-'
-
 test_expect_success 'init with GIT_DEFAULT_REF_FORMAT=garbage' '
 	test_when_finished "rm -rf refformat" &&
 	cat >expect <<-EOF &&
@@ -576,15 +620,90 @@ test_expect_success 'init with GIT_DEFAULT_REF_FORMAT=garbage' '
 	test_cmp expect err
 '
 
-test_expect_success 'init with --ref-format=files' '
+test_expect_success 'init warns about invalid init.defaultRefFormat' '
+	test_when_finished "rm -rf repo" &&
+	test_config_global init.defaultRefFormat garbage &&
+
+	echo "warning: unknown ref storage format ${SQ}garbage${SQ}" >expect &&
+	git init repo 2>err &&
+	test_cmp expect err &&
+
+	git -C repo rev-parse --show-ref-format >actual &&
+	echo $GIT_DEFAULT_REF_FORMAT >expected &&
+	test_cmp expected actual
+'
+
+backends="files reftable"
+for format in $backends
+do
+	test_expect_success DEFAULT_REPO_FORMAT "init with GIT_DEFAULT_REF_FORMAT=$format" '
+		test_when_finished "rm -rf refformat" &&
+		GIT_DEFAULT_REF_FORMAT=$format git init refformat &&
+
+		if test $format = files
+		then
+			test_must_fail git -C refformat config extensions.refstorage &&
+			echo 0 >expect
+		else
+			git -C refformat config extensions.refstorage &&
+			echo 1 >expect
+		fi &&
+		git -C refformat config core.repositoryformatversion >actual &&
+		test_cmp expect actual &&
+
+		echo $format >expect &&
+		git -C refformat rev-parse --show-ref-format >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "init with --ref-format=$format" '
+		test_when_finished "rm -rf refformat" &&
+		git init --ref-format=$format refformat &&
+		echo $format >expect &&
+		git -C refformat rev-parse --show-ref-format >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "init with init.defaultRefFormat=$format" '
+		test_when_finished "rm -rf refformat" &&
+		test_config_global init.defaultRefFormat $format &&
+		(
+			sane_unset GIT_DEFAULT_REF_FORMAT &&
+			git init refformat
+		) &&
+
+		echo $format >expect &&
+		git -C refformat rev-parse --show-ref-format >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "--ref-format=$format overrides GIT_DEFAULT_REF_FORMAT" '
+		test_when_finished "rm -rf refformat" &&
+		GIT_DEFAULT_REF_FORMAT=garbage git init --ref-format=$format refformat &&
+		echo $format >expect &&
+		git -C refformat rev-parse --show-ref-format >actual &&
+		test_cmp expect actual
+	'
+done
+
+test_expect_success "--ref-format= overrides GIT_DEFAULT_REF_FORMAT" '
 	test_when_finished "rm -rf refformat" &&
-	git init --ref-format=files refformat &&
-	echo files >expect &&
+	GIT_DEFAULT_REF_FORMAT=files git init --ref-format=reftable refformat &&
+	echo reftable >expect &&
+	git -C refformat rev-parse --show-ref-format >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success "GIT_DEFAULT_REF_FORMAT= overrides init.defaultRefFormat" '
+	test_when_finished "rm -rf refformat" &&
+	test_config_global init.defaultRefFormat files &&
+
+	GIT_DEFAULT_REF_FORMAT=reftable git init refformat &&
+	echo reftable >expect &&
 	git -C refformat rev-parse --show-ref-format >actual &&
 	test_cmp expect actual
 '
 
-backends="files reftable"
 for from_format in $backends
 do
 	test_expect_success "re-init with same format ($from_format)" '