# [PATCH 2/2] submodule: Port init from shell to C

16 messages from 2016-01-15 to 2016-01-22. Participants: Stefan Beller, Junio C Hamano, Johannes Sixt.
Thread: https://gitlist.dev/t/41205

## Stefan Beller, 2016-01-15 23:37

Subject: [PATCH 0/2] Port `git submodule init` from shell to C
Message-ID: <1452901035-1802-1-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1452901035-1802-1-git-send-email-sbeller%40google.com

```
The first patch is a reroll of "[PATCH] submodule: Port resolve_relative_url
from shell to C" and the second patch is new.

This applies on top of origin/sb/submodule-parallel-update, as it makes use
of the recorded update strategy in the submodule configuration.

Thanks,
Stefan

Stefan Beller (2):
  submodule: Port resolve_relative_url from shell to C
  submodule: Port init from shell to C

 builtin/submodule--helper.c | 330 +++++++++++++++++++++++++++++++++++++++++++-
 git-submodule.sh            | 118 +---------------
 t/t0060-path-utils.sh       |  42 ++++++
 3 files changed, 370 insertions(+), 120 deletions(-)

-- 
2.7.0.rc0.37.gb4a0220.dirty

```

## Stefan Beller, 2016-01-15 23:37

Subject: [PATCH 1/2] submodule: Port resolve_relative_url from shell to C
Message-ID: <1452901035-1802-2-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1452901035-1802-2-git-send-email-sbeller%40google.com
In-Reply-To: <1452901035-1802-1-git-send-email-sbeller@google.com>

```
Later on we want to automatically call `git submodule init`
from other commands, such that the user doesn't have to initialize
the submodule themself. As these other commands are written in C
already, we'd need the init functionality in C, too. The
`resolve_relative_url` function is a large part of that init
functionality, so start by porting this function to C.

To create the tests in t0060, the function `resolve_relative_url`
was temporarily enhanced to write all inputs and output to disk
when running the test suite. The added tests in this patch are
a small selection thereof.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

> ... and ends here can easily be rewritten to become a single strbuf_addf()
> without the xstrdup()s and without the early exit (at the cost of some
> additional ?: conditionals in the arguments).

I did not go that route, as I could not find a viable solution there.
It looks easy, but it is not, because we have a starts_with_dot_slash
check which is either applied to remoteurl alone or a combination of all of the inputs
(remoteurl=".", colonsep = "/", url + ./....)
 
 builtin/submodule--helper.c | 215 +++++++++++++++++++++++++++++++++++++++++++-
 git-submodule.sh            |  81 +----------------
 t/t0060-path-utils.sh       |  42 +++++++++
 3 files changed, 260 insertions(+), 78 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 8002187..1484b36 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -9,6 +9,217 @@
 #include "submodule-config.h"
 #include "string-list.h"
 #include "run-command.h"
+#include "remote.h"
+#include "refs.h"
+#include "connect.h"
+
+static char *get_default_remote(void)
+{
+	char *dest = NULL, *ret;
+	unsigned char sha1[20];
+	int flag = 0;
+	struct strbuf sb = STRBUF_INIT;
+	const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, &flag);
+
+	if (!refname)
+		die("No such ref: HEAD");
+
+	/* detached HEAD */
+	if (!strcmp(refname, "HEAD"))
+		return xstrdup("origin");
+
+	if (!skip_prefix(refname, "refs/heads/", &refname))
+		die(_("Expecting a full ref name, got %s"), refname);
+
+	strbuf_addf(&sb, "branch.%s.remote", refname);
+	if (git_config_get_string(sb.buf, &dest))
+		ret = xstrdup("origin");
+	else
+		ret = xstrdup(dest);
+
+	strbuf_release(&sb);
+	return ret;
+}
+
+static int starts_with_dot_slash(const char *str)
+{
+	return str[0] == '.' && is_dir_sep(str[1]);
+}
+
+static int starts_with_dot_dot_slash(const char *str)
+{
+	return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]);
+}
+
+static char *last_dir_separator(char *str)
+{
+	char *p = str + strlen(str);
+	while (p-- > str)
+		if (is_dir_sep(*p))
+			return p;
+	return NULL;
+}
+
+/*
+ * Returns 1 if it was the last chop before ':'.
+ */
+static int chop_last_dir(char **remoteurl, int is_relative)
+{
+	char *rfind = last_dir_separator(*remoteurl);
+	if (rfind) {
+		*rfind = '\0';
+		return 0;
+	}
+
+	rfind = strrchr(*remoteurl, ':');
+	if (rfind) {
+		*rfind = '\0';
+		return 1;
+	}
+
+	if (is_relative || !strcmp(".", *remoteurl))
+		die(_("cannot strip one component off url '%s'"),
+			*remoteurl);
+
+	free(*remoteurl);
+	*remoteurl = xstrdup(".");
+	return 0;
+}
+
+/*
+ * The `url` argument is the URL that navigates to the submodule origin
+ * repo. When relative, this URL is relative to the superproject origin
+ * URL repo. The `up_path` argument, if specified, is the relative
+ * path that navigates from the submodule working tree to the superproject
+ * working tree. Returns the origin URL of the submodule.
+ *
+ * Return either an absolute URL or filesystem path (if the superproject
+ * origin URL is an absolute URL or filesystem path, respectively) or a
+ * relative file system path (if the superproject origin URL is a relative
+ * file system path).
+ *
+ * When the output is a relative file system path, the path is either
+ * relative to the submodule working tree, if up_path is specified, or to
+ * the superproject working tree otherwise.
+ *
+ * NEEDSWORK: This works incorrectly on the domain and protocol part.
+ * remote_url      url              outcome          correct
+ * http://a.com/b  ../c             http://a.com/c   yes
+ * http://a.com/b  ../../c          http://c         no (domain should be kept)
+ * http://a.com/b  ../../../c       http:/c          no
+ * http://a.com/b  ../../../../c    http:c           no
+ * http://a.com/b  ../../../../../c    .:c           no
+ */
+static char *relative_url(const char *remote_url,
+				const char *url,
+				const char *up_path)
+{
+	int is_relative = 0;
+	int colonsep = 0;
+	char *out;
+	char *remoteurl = xstrdup(remote_url);
+	struct strbuf sb = STRBUF_INIT;
+	size_t len = strlen(remoteurl);
+
+	if (is_dir_sep(remoteurl[len]))
+		remoteurl[len] = '\0';
+
+	if (!url_is_local_not_ssh(remoteurl) || is_absolute_path(remoteurl))
+		is_relative = 0;
+	else {
+		is_relative = 1;
+		/*
+		 * Prepend a './' to ensure all relative
+		 * remoteurls start with './' or '../'
+		 */
+		if (!starts_with_dot_slash(remoteurl) &&
+		    !starts_with_dot_dot_slash(remoteurl)) {
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "./%s", remoteurl);
+			free(remoteurl);
+			remoteurl = strbuf_detach(&sb, NULL);
+		}
+	}
+	/*
+	 * When the url starts with '../', remove that and the
+	 * last directory in remoteurl.
+	 */
+	while (url) {
+		if (starts_with_dot_dot_slash(url)) {
+			url += 3;
+			colonsep |= chop_last_dir(&remoteurl, is_relative);
+		} else if (starts_with_dot_slash(url))
+			url += 2;
+		else
+			break;
+	}
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s%s%s", remoteurl, colonsep ? ":" : "/", url);
+
+	if (starts_with_dot_slash(sb.buf))
+		out = xstrdup(sb.buf + 2);
+	else
+		out = xstrdup(sb.buf);
+	strbuf_reset(&sb);
+
+	free(remoteurl);
+	if (!up_path || !is_relative)
+		return out;
+
+	strbuf_addf(&sb, "%s%s", up_path, out);
+	free(out);
+	return strbuf_detach(&sb, NULL);
+}
+
+static int resolve_relative_url(int argc, const char **argv, const char *prefix)
+{
+	char *remoteurl = NULL;
+	char *remote = get_default_remote();
+	const char *up_path = NULL;
+	char *res;
+	const char *url;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (argc != 2 && argc != 3)
+		die("resolve-relative-url only accepts one or two arguments");
+
+	url = argv[1];
+	strbuf_addf(&sb, "remote.%s.url", remote);
+	free(remote);
+
+	if (git_config_get_string(sb.buf, &remoteurl))
+		/* the repository is its own authoritative upstream */
+		remoteurl = xgetcwd();
+
+	if (argc == 3)
+		up_path = argv[2];
+
+	res = relative_url(remoteurl, url, up_path);
+	puts(res);
+	free(res);
+	return 0;
+}
+
+static int resolve_relative_url_test(int argc, const char **argv, const char *prefix)
+{
+	char *remoteurl, *res;
+	const char *up_path, *url;
+
+	if (argc != 4)
+		die("resolve-relative-url-test only accepts three arguments: <up_path> <remoteurl> <url>");
+
+	up_path = argv[1];
+	remoteurl = xstrdup(argv[2]);
+	url = argv[3];
+
+	if (!strcmp(up_path, "(null)"))
+		up_path = NULL;
+
+	res = relative_url(remoteurl, url, up_path);
+	puts(res);
+	free(res);
+	return 0;
+}
 
 struct module_list {
 	const struct cache_entry **entries;
@@ -502,7 +713,9 @@ static struct cmd_struct commands[] = {
 	{"list", module_list},
 	{"name", module_name},
 	{"clone", module_clone},
-	{"update-clone", update_clone}
+	{"update-clone", update_clone},
+	{"resolve-relative-url", resolve_relative_url},
+	{"resolve-relative-url-test", resolve_relative_url_test},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 10c5af9..615ef9b 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -46,79 +46,6 @@ prefix=
 custom_name=
 depth=
 
-# The function takes at most 2 arguments. The first argument is the
-# URL that navigates to the submodule origin repo. When relative, this URL
-# is relative to the superproject origin URL repo. The second up_path
-# argument, if specified, is the relative path that navigates
-# from the submodule working tree to the superproject working tree.
-#
-# The output of the function is the origin URL of the submodule.
-#
-# The output will either be an absolute URL or filesystem path (if the
-# superproject origin URL is an absolute URL or filesystem path,
-# respectively) or a relative file system path (if the superproject
-# origin URL is a relative file system path).
-#
-# When the output is a relative file system path, the path is either
-# relative to the submodule working tree, if up_path is specified, or to
-# the superproject working tree otherwise.
-resolve_relative_url ()
-{
-	remote=$(get_default_remote)
-	remoteurl=$(git config "remote.$remote.url") ||
-		remoteurl=$(pwd) # the repository is its own authoritative upstream
-	url="$1"
-	remoteurl=${remoteurl%/}
-	sep=/
-	up_path="$2"
-
-	case "$remoteurl" in
-	*:*|/*)
-		is_relative=
-		;;
-	./*|../*)
-		is_relative=t
-		;;
-	*)
-		is_relative=t
-		remoteurl="./$remoteurl"
-		;;
-	esac
-
-	while test -n "$url"
-	do
-		case "$url" in
-		../*)
-			url="${url#../}"
-			case "$remoteurl" in
-			*/*)
-				remoteurl="${remoteurl%/*}"
-				;;
-			*:*)
-				remoteurl="${remoteurl%:*}"
-				sep=:
-				;;
-			*)
-				if test -z "$is_relative" || test "." = "$remoteurl"
-				then
-					die "$(eval_gettext "cannot strip one component off url '\$remoteurl'")"
-				else
-					remoteurl=.
-				fi
-				;;
-			esac
-			;;
-		./*)
-			url="${url#./}"
-			;;
-		*)
-			break;;
-		esac
-	done
-	remoteurl="$remoteurl$sep${url%/}"
-	echo "${is_relative:+${up_path}}${remoteurl#./}"
-}
-
 # Resolve a path to be relative to another path.  This is intended for
 # converting submodule paths when git-submodule is run in a subdirectory
 # and only handles paths where the directory separator is '/'.
@@ -281,7 +208,7 @@ cmd_add()
 		die "$(gettext "Relative path can only be used from the toplevel of the working tree")"
 
 		# dereference source url relative to parent's url
-		realrepo=$(resolve_relative_url "$repo") || exit
+		realrepo=$(git submodule--helper resolve-relative-url "$repo") || exit
 		;;
 	*:*|/*)
 		# absolute url
@@ -485,7 +412,7 @@ cmd_init()
 			# Possibly a url relative to parent
 			case "$url" in
 			./*|../*)
-				url=$(resolve_relative_url "$url") || exit
+				url=$(git submodule--helper resolve-relative-url "$url") || exit
 				;;
 			esac
 			git config submodule."$name".url "$url" ||
@@ -1176,9 +1103,9 @@ cmd_sync()
 			# guarantee a trailing /
 			up_path=${up_path%/}/ &&
 			# path from submodule work tree to submodule origin repo
-			sub_origin_url=$(resolve_relative_url "$url" "$up_path") &&
+			sub_origin_url=$(git submodule--helper resolve-relative-url "$url" "$up_path") &&
 			# path from superproject work tree to submodule origin repo
-			super_config_url=$(resolve_relative_url "$url") || exit
+			super_config_url=$(git submodule--helper resolve-relative-url "$url") || exit
 			;;
 		*)
 			sub_origin_url="$url"
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index 627ef85..8a1579c 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -19,6 +19,13 @@ relative_path() {
 	"test \"\$(test-path-utils relative_path '$1' '$2')\" = '$expected'"
 }
 
+test_submodule_relative_url() {
+	test_expect_success "test_submodule_relative_url: $1 $2 $3 => $4" "
+		actual=\$(git submodule--helper resolve-relative-url-test '$1' '$2' '$3') &&
+		test \"\$actual\" = '$4'
+	"
+}
+
 test_git_path() {
 	test_expect_success "git-path $1 $2 => $3" "
 		$1 git rev-parse --git-path $2 >actual &&
@@ -286,4 +293,39 @@ test_git_path GIT_COMMON_DIR=bar config                   bar/config
 test_git_path GIT_COMMON_DIR=bar packed-refs              bar/packed-refs
 test_git_path GIT_COMMON_DIR=bar shallow                  bar/shallow
 
+test_submodule_relative_url "(null)" "../foo/bar" "../sub/a/b/c" "../foo/sub/a/b/c"
+test_submodule_relative_url "../../../" "../foo/bar" "../sub/a/b/c" "../../../../foo/sub/a/b/c"
+test_submodule_relative_url "(null)" "../foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "../" "../foo/bar" "../submodule" "../../foo/submodule"
+test_submodule_relative_url "(null)" "../foo/submodule" "../submodule" "../foo/submodule"
+test_submodule_relative_url "../" "../foo/submodule" "../submodule" "../../foo/submodule"
+test_submodule_relative_url "(null)" "../foo" "../submodule" "../submodule"
+test_submodule_relative_url "../" "../foo" "../submodule" "../../submodule"
+test_submodule_relative_url "(null)" "./foo/bar" "../submodule" "foo/submodule"
+test_submodule_relative_url "../" "./foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "(null)" "./foo" "../submodule" "submodule"
+test_submodule_relative_url "../" "./foo" "../submodule" "../submodule"
+test_submodule_relative_url "(null)" "//somewhere else/repo" "../subrepo" "//somewhere else/subrepo"
+test_submodule_relative_url "(null)" "/u//trash directory.t7406-submodule-update/subsuper_update_r" "../subsubsuper_update_r" "/u//trash directory.t7406-submodule-update/subsubsuper_update_r"
+test_submodule_relative_url "(null)" "/u//trash directory.t7406-submodule-update/super_update_r2" "../subsuper_update_r" "/u//trash directory.t7406-submodule-update/subsuper_update_r"
+test_submodule_relative_url "(null)" "/u/trash directory.t3600-rm/." "../." "/u/trash directory.t3600-rm/."
+test_submodule_relative_url "(null)" "/u/trash directory.t3600-rm" "./." "/u/trash directory.t3600-rm/."
+test_submodule_relative_url "(null)" "/u/trash directory.t7400-submodule-basic/addtest" "../repo" "/u/trash directory.t7400-submodule-basic/repo"
+test_submodule_relative_url "../" "/u/trash directory.t7400-submodule-basic/addtest" "../repo" "/u/trash directory.t7400-submodule-basic/repo"
+test_submodule_relative_url "(null)" "/u/trash directory.t7400-submodule-basic" "./å äö" "/u/trash directory.t7400-submodule-basic/å äö"
+test_submodule_relative_url "(null)" "/u/trash directory.t7403-submodule-sync/." "../submodule" "/u/trash directory.t7403-submodule-sync/submodule"
+test_submodule_relative_url "(null)" "/u/trash directory.t7407-submodule-foreach/submodule" "../submodule" "/u/trash directory.t7407-submodule-foreach/submodule"
+test_submodule_relative_url "(null)" "/u/trash directory.t7409-submodule-detached-worktree/home2/../remote" "../bundle1" "/u/trash directory.t7409-submodule-detached-worktree/home2/../bundle1"
+test_submodule_relative_url "(null)" "/u/trash directory.t7613-merge-submodule/submodule_update_repo" "./." "/u/trash directory.t7613-merge-submodule/submodule_update_repo/."
+test_submodule_relative_url "(null)" "file:///tmp/repo" "../subrepo" "file:///tmp/subrepo"
+test_submodule_relative_url "(null)" "foo/bar" "../submodule" "foo/submodule"
+test_submodule_relative_url "../" "foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "(null)" "foo" "../submodule" "submodule"
+test_submodule_relative_url "../" "foo" "../submodule" "../submodule"
+test_submodule_relative_url "(null)" "helper:://hostname/repo" "../subrepo" "helper:://hostname/subrepo"
+test_submodule_relative_url "(null)" "ssh://hostname/repo" "../subrepo" "ssh://hostname/subrepo"
+test_submodule_relative_url "(null)" "ssh://hostname:22/repo" "../subrepo" "ssh://hostname:22/subrepo"
+test_submodule_relative_url "(null)" "user@host:path/to/repo" "../subrepo" "user@host:path/to/subrepo"
+test_submodule_relative_url "(null)" "user@host:repo" "../subrepo" "user@host:subrepo"
+
 test_done
-- 
2.7.0.rc0.37.gb4a0220.dirty

```

## Stefan Beller, 2016-01-15 23:37

Subject: [PATCH 2/2] submodule: Port init from shell to C
Message-ID: <1452901035-1802-3-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1452901035-1802-3-git-send-email-sbeller%40google.com
In-Reply-To: <1452901035-1802-1-git-send-email-sbeller@google.com>

```
By having the `init` functionality in C, we can reference it easier from
other parts in the code.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 builtin/submodule--helper.c | 115 ++++++++++++++++++++++++++++++++++++++++++--
 git-submodule.sh            |  39 +--------------
 2 files changed, 111 insertions(+), 43 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1484b36..c7bd38a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -221,6 +221,115 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static int git_submodule_config(const char *var, const char *value, void *cb)
+{
+	return parse_submodule_config_option(var, value);
+}
+
+static void init_submodule(const char *path, const char *prefix)
+{
+	const struct submodule *sub;
+	struct strbuf sb = STRBUF_INIT;
+	char *url = NULL;
+	const char *upd = NULL;
+	const char *displaypath = relative_path(xgetcwd(), prefix, &sb);;
+
+	/* Only loads from .gitmodules, no overlay with .git/config */
+	gitmodules_config();
+
+	sub = submodule_from_path(null_sha1, path);
+
+	/*
+	 * Copy url setting when it is not set yet.
+	 * To look up the url in .git/config, we must not fall back to
+	 * .gitmodules, so look it up directly.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.url", sub->name);
+	if (git_config_get_string(sb.buf, &url)) {
+		url = xstrdup(sub->url); // as overlayed by .gitmodules
+
+		if (!url)
+			die(_("No url found for submodule path '%s' in .gitmodules"),
+				displaypath);
+
+		/* Possibly a url relative to parent */
+		if (starts_with_dot_dot_slash(url) ||
+		    starts_with_dot_slash(url)) {
+			char *remoteurl;
+			char *remote = get_default_remote();
+			struct strbuf remotesb = STRBUF_INIT;
+			strbuf_addf(&remotesb, "remote.%s.url", remote);
+			free(remote);
+
+			if (git_config_get_string(remotesb.buf, &remoteurl))
+				/*
+				 * The repository is its own
+				 * authoritative upstream
+				 */
+				remoteurl = xgetcwd();
+			url = relative_url(remoteurl, url, NULL);
+			strbuf_release(&remotesb);
+		}
+
+		if (git_config_set(sb.buf, url))
+			die(_("Failed to register url for submodule path '%s'"),
+			    displaypath);
+
+		printf(_("Submodule '%s' (%s) registered for path '%s'\n"),
+			sub->name, url, displaypath);
+		free(url);
+	}
+
+	/* Copy "update" setting when it is not set yet */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.update", sub->name);
+	if (git_config_get_string_const(sb.buf, &upd) && sub->update) {
+		upd = sub->update;
+		if (strcmp(sub->update, "checkout") &&
+		    strcmp(sub->update, "rebase") &&
+		    strcmp(sub->update, "merge") &&
+		    strcmp(sub->update, "none")) {
+			fprintf(stderr, _("warning: unknown update mode '%s' suggested for submodule '%s'\n"),
+				upd, sub->name);
+			upd = "none";
+		}
+		if (git_config_set(sb.buf, upd))
+			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
+	}
+	strbuf_release(&sb);
+}
+
+static int module_init(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	int i;
+
+	struct option module_init_options[] = {
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("alternative anchor for relative paths")),
+		OPT__QUIET(&quiet, "Suppress output for initialzing a submodule"),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper init [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_init_options,
+			     git_submodule_helper_usage, 0);
+
+	if (argc == 0)
+		die(_("Pass at least one submodule"));
+
+	for (i = 0; i < argc; i++)
+		init_submodule(argv[i], prefix);
+
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -466,11 +575,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int git_submodule_config(const char *var, const char *value, void *cb)
-{
-	return parse_submodule_config_option(var, value);
-}
-
 struct submodule_update_clone {
 	/* states */
 	int count;
@@ -716,6 +820,7 @@ static struct cmd_struct commands[] = {
 	{"update-clone", update_clone},
 	{"resolve-relative-url", resolve_relative_url},
 	{"resolve-relative-url-test", resolve_relative_url_test},
+	{"init", module_init}
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 615ef9b..6fce0dc 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -398,45 +398,8 @@ cmd_init()
 	while read mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode"
-		name=$(git submodule--helper name "$sm_path") || exit
-
-		displaypath=$(relative_path "$sm_path")
-
-		# Copy url setting when it is not set yet
-		if test -z "$(git config "submodule.$name.url")"
-		then
-			url=$(git config -f .gitmodules submodule."$name".url)
-			test -z "$url" &&
-			die "$(eval_gettext "No url found for submodule path '\$displaypath' in .gitmodules")"
-
-			# Possibly a url relative to parent
-			case "$url" in
-			./*|../*)
-				url=$(git submodule--helper resolve-relative-url "$url") || exit
-				;;
-			esac
-			git config submodule."$name".url "$url" ||
-			die "$(eval_gettext "Failed to register url for submodule path '\$displaypath'")"
 
-			say "$(eval_gettext "Submodule '\$name' (\$url) registered for path '\$displaypath'")"
-		fi
-
-		# Copy "update" setting when it is not set yet
-		if upd="$(git config -f .gitmodules submodule."$name".update)" &&
-		   test -n "$upd" &&
-		   test -z "$(git config submodule."$name".update)"
-		then
-			case "$upd" in
-			checkout | rebase | merge | none)
-				;; # known modes of updating
-			*)
-				echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
-				upd=none
-				;;
-			esac
-			git config submodule."$name".update "$upd" ||
-			die "$(eval_gettext "Failed to register update mode for submodule path '\$displaypath'")"
-		fi
+		git submodule--helper init ${GIT_QUIET:+--quiet} "$sm_path" || exit
 	done
 }
 
-- 
2.7.0.rc0.37.gb4a0220.dirty

```

## Junio C Hamano, 2016-01-19 23:17

Subject: Re: [PATCH 0/2] Port `git submodule init` from shell to C
Message-ID: <xmqqa8o188i0.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqa8o188i0.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <1452901035-1802-1-git-send-email-sbeller@google.com>

```
I've queued these with a bit of tweak in their log message.

Thanks.

```

## Stefan Beller, 2016-01-20 02:03

Subject: [PATCHv2 0/2] Port `git submodule init` from shell to C
Message-ID: <1453255396-31942-1-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1453255396-31942-1-git-send-email-sbeller%40google.com
In-Reply-To: <xmqqa8o188i0.fsf@gitster.mtv.corp.google.com>

```
This replaces sb/submodule-init.
As I was crafting another series on top of this series I noticed a two bugs,
so I am resending it fixed.

* honor the quiet setting
* print to stderr instead of stdout. (In the next series we want to
  call init_submodule from within update_clone whose stdout is piped into
  git-submodule.sh, so stderr is the only way to talk to the user)

Thanks,
Stefan

The interdiff:

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c7bd38a..fecc9aa 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -226,7 +226,7 @@ static int git_submodule_config(const char *var, const char *value, void *cb)
        return parse_submodule_config_option(var, value);
 }
 
-static void init_submodule(const char *path, const char *prefix)
+static void init_submodule(const char *path, const char *prefix, int quiet)
 {
        const struct submodule *sub;
        struct strbuf sb = STRBUF_INIT;
@@ -275,9 +275,9 @@ static void init_submodule(const char *path, const char *prefix)
                if (git_config_set(sb.buf, url))
                        die(_("Failed to register url for submodule path '%s'"),
                            displaypath);
-
-               printf(_("Submodule '%s' (%s) registered for path '%s'\n"),
-                       sub->name, url, displaypath);
+               if (!quiet)
+                       fprintf(stderr, _("Submodule '%s' (%s) registered for path '%s'\n"),
+                               sub->name, url, displaypath);
                free(url);
        }
 
@@ -325,7 +325,7 @@ static int module_init(int argc, const char **argv, const char *prefix)
                die(_("Pass at least one submodule"));
 
        for (i = 0; i < argc; i++)
-               init_submodule(argv[i], prefix);
+               init_submodule(argv[i], prefix, quiet);
 
        return 0;
 }


Stefan Beller (2):
  submodule: port resolve_relative_url from shell to C
  submodule: port init from shell to C

 builtin/submodule--helper.c | 330 +++++++++++++++++++++++++++++++++++++++++++-
 git-submodule.sh            | 118 +---------------
 t/t0060-path-utils.sh       |  42 ++++++
 3 files changed, 370 insertions(+), 120 deletions(-)

-- 
2.7.0.rc0.44.g6033384.dirty

```

## Stefan Beller, 2016-01-20 02:03

Subject: [PATCHv2 1/2] submodule: port resolve_relative_url from shell to C
Message-ID: <1453255396-31942-2-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1453255396-31942-2-git-send-email-sbeller%40google.com
In-Reply-To: <1453255396-31942-1-git-send-email-sbeller@google.com>

```
Later on we want to automatically call `git submodule init` from
other commands, such that the users don't have to initialize the
submodule themselves.  As these other commands are written in C
already, we'd need the init functionality in C, too.  The
`resolve_relative_url` function is a large part of that init
functionality, so start by porting this function to C.

To create the tests in t0060, the function `resolve_relative_url`
was temporarily enhanced to write all inputs and output to disk
when running the test suite. The added tests in this patch are
a small selection thereof.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/submodule--helper.c | 215 +++++++++++++++++++++++++++++++++++++++++++-
 git-submodule.sh            |  81 +----------------
 t/t0060-path-utils.sh       |  42 +++++++++
 3 files changed, 260 insertions(+), 78 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 8002187..1484b36 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -9,6 +9,217 @@
 #include "submodule-config.h"
 #include "string-list.h"
 #include "run-command.h"
+#include "remote.h"
+#include "refs.h"
+#include "connect.h"
+
+static char *get_default_remote(void)
+{
+	char *dest = NULL, *ret;
+	unsigned char sha1[20];
+	int flag = 0;
+	struct strbuf sb = STRBUF_INIT;
+	const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, &flag);
+
+	if (!refname)
+		die("No such ref: HEAD");
+
+	/* detached HEAD */
+	if (!strcmp(refname, "HEAD"))
+		return xstrdup("origin");
+
+	if (!skip_prefix(refname, "refs/heads/", &refname))
+		die(_("Expecting a full ref name, got %s"), refname);
+
+	strbuf_addf(&sb, "branch.%s.remote", refname);
+	if (git_config_get_string(sb.buf, &dest))
+		ret = xstrdup("origin");
+	else
+		ret = xstrdup(dest);
+
+	strbuf_release(&sb);
+	return ret;
+}
+
+static int starts_with_dot_slash(const char *str)
+{
+	return str[0] == '.' && is_dir_sep(str[1]);
+}
+
+static int starts_with_dot_dot_slash(const char *str)
+{
+	return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]);
+}
+
+static char *last_dir_separator(char *str)
+{
+	char *p = str + strlen(str);
+	while (p-- > str)
+		if (is_dir_sep(*p))
+			return p;
+	return NULL;
+}
+
+/*
+ * Returns 1 if it was the last chop before ':'.
+ */
+static int chop_last_dir(char **remoteurl, int is_relative)
+{
+	char *rfind = last_dir_separator(*remoteurl);
+	if (rfind) {
+		*rfind = '\0';
+		return 0;
+	}
+
+	rfind = strrchr(*remoteurl, ':');
+	if (rfind) {
+		*rfind = '\0';
+		return 1;
+	}
+
+	if (is_relative || !strcmp(".", *remoteurl))
+		die(_("cannot strip one component off url '%s'"),
+			*remoteurl);
+
+	free(*remoteurl);
+	*remoteurl = xstrdup(".");
+	return 0;
+}
+
+/*
+ * The `url` argument is the URL that navigates to the submodule origin
+ * repo. When relative, this URL is relative to the superproject origin
+ * URL repo. The `up_path` argument, if specified, is the relative
+ * path that navigates from the submodule working tree to the superproject
+ * working tree. Returns the origin URL of the submodule.
+ *
+ * Return either an absolute URL or filesystem path (if the superproject
+ * origin URL is an absolute URL or filesystem path, respectively) or a
+ * relative file system path (if the superproject origin URL is a relative
+ * file system path).
+ *
+ * When the output is a relative file system path, the path is either
+ * relative to the submodule working tree, if up_path is specified, or to
+ * the superproject working tree otherwise.
+ *
+ * NEEDSWORK: This works incorrectly on the domain and protocol part.
+ * remote_url      url              outcome          correct
+ * http://a.com/b  ../c             http://a.com/c   yes
+ * http://a.com/b  ../../c          http://c         no (domain should be kept)
+ * http://a.com/b  ../../../c       http:/c          no
+ * http://a.com/b  ../../../../c    http:c           no
+ * http://a.com/b  ../../../../../c    .:c           no
+ */
+static char *relative_url(const char *remote_url,
+				const char *url,
+				const char *up_path)
+{
+	int is_relative = 0;
+	int colonsep = 0;
+	char *out;
+	char *remoteurl = xstrdup(remote_url);
+	struct strbuf sb = STRBUF_INIT;
+	size_t len = strlen(remoteurl);
+
+	if (is_dir_sep(remoteurl[len]))
+		remoteurl[len] = '\0';
+
+	if (!url_is_local_not_ssh(remoteurl) || is_absolute_path(remoteurl))
+		is_relative = 0;
+	else {
+		is_relative = 1;
+		/*
+		 * Prepend a './' to ensure all relative
+		 * remoteurls start with './' or '../'
+		 */
+		if (!starts_with_dot_slash(remoteurl) &&
+		    !starts_with_dot_dot_slash(remoteurl)) {
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "./%s", remoteurl);
+			free(remoteurl);
+			remoteurl = strbuf_detach(&sb, NULL);
+		}
+	}
+	/*
+	 * When the url starts with '../', remove that and the
+	 * last directory in remoteurl.
+	 */
+	while (url) {
+		if (starts_with_dot_dot_slash(url)) {
+			url += 3;
+			colonsep |= chop_last_dir(&remoteurl, is_relative);
+		} else if (starts_with_dot_slash(url))
+			url += 2;
+		else
+			break;
+	}
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s%s%s", remoteurl, colonsep ? ":" : "/", url);
+
+	if (starts_with_dot_slash(sb.buf))
+		out = xstrdup(sb.buf + 2);
+	else
+		out = xstrdup(sb.buf);
+	strbuf_reset(&sb);
+
+	free(remoteurl);
+	if (!up_path || !is_relative)
+		return out;
+
+	strbuf_addf(&sb, "%s%s", up_path, out);
+	free(out);
+	return strbuf_detach(&sb, NULL);
+}
+
+static int resolve_relative_url(int argc, const char **argv, const char *prefix)
+{
+	char *remoteurl = NULL;
+	char *remote = get_default_remote();
+	const char *up_path = NULL;
+	char *res;
+	const char *url;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (argc != 2 && argc != 3)
+		die("resolve-relative-url only accepts one or two arguments");
+
+	url = argv[1];
+	strbuf_addf(&sb, "remote.%s.url", remote);
+	free(remote);
+
+	if (git_config_get_string(sb.buf, &remoteurl))
+		/* the repository is its own authoritative upstream */
+		remoteurl = xgetcwd();
+
+	if (argc == 3)
+		up_path = argv[2];
+
+	res = relative_url(remoteurl, url, up_path);
+	puts(res);
+	free(res);
+	return 0;
+}
+
+static int resolve_relative_url_test(int argc, const char **argv, const char *prefix)
+{
+	char *remoteurl, *res;
+	const char *up_path, *url;
+
+	if (argc != 4)
+		die("resolve-relative-url-test only accepts three arguments: <up_path> <remoteurl> <url>");
+
+	up_path = argv[1];
+	remoteurl = xstrdup(argv[2]);
+	url = argv[3];
+
+	if (!strcmp(up_path, "(null)"))
+		up_path = NULL;
+
+	res = relative_url(remoteurl, url, up_path);
+	puts(res);
+	free(res);
+	return 0;
+}
 
 struct module_list {
 	const struct cache_entry **entries;
@@ -502,7 +713,9 @@ static struct cmd_struct commands[] = {
 	{"list", module_list},
 	{"name", module_name},
 	{"clone", module_clone},
-	{"update-clone", update_clone}
+	{"update-clone", update_clone},
+	{"resolve-relative-url", resolve_relative_url},
+	{"resolve-relative-url-test", resolve_relative_url_test},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 10c5af9..615ef9b 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -46,79 +46,6 @@ prefix=
 custom_name=
 depth=
 
-# The function takes at most 2 arguments. The first argument is the
-# URL that navigates to the submodule origin repo. When relative, this URL
-# is relative to the superproject origin URL repo. The second up_path
-# argument, if specified, is the relative path that navigates
-# from the submodule working tree to the superproject working tree.
-#
-# The output of the function is the origin URL of the submodule.
-#
-# The output will either be an absolute URL or filesystem path (if the
-# superproject origin URL is an absolute URL or filesystem path,
-# respectively) or a relative file system path (if the superproject
-# origin URL is a relative file system path).
-#
-# When the output is a relative file system path, the path is either
-# relative to the submodule working tree, if up_path is specified, or to
-# the superproject working tree otherwise.
-resolve_relative_url ()
-{
-	remote=$(get_default_remote)
-	remoteurl=$(git config "remote.$remote.url") ||
-		remoteurl=$(pwd) # the repository is its own authoritative upstream
-	url="$1"
-	remoteurl=${remoteurl%/}
-	sep=/
-	up_path="$2"
-
-	case "$remoteurl" in
-	*:*|/*)
-		is_relative=
-		;;
-	./*|../*)
-		is_relative=t
-		;;
-	*)
-		is_relative=t
-		remoteurl="./$remoteurl"
-		;;
-	esac
-
-	while test -n "$url"
-	do
-		case "$url" in
-		../*)
-			url="${url#../}"
-			case "$remoteurl" in
-			*/*)
-				remoteurl="${remoteurl%/*}"
-				;;
-			*:*)
-				remoteurl="${remoteurl%:*}"
-				sep=:
-				;;
-			*)
-				if test -z "$is_relative" || test "." = "$remoteurl"
-				then
-					die "$(eval_gettext "cannot strip one component off url '\$remoteurl'")"
-				else
-					remoteurl=.
-				fi
-				;;
-			esac
-			;;
-		./*)
-			url="${url#./}"
-			;;
-		*)
-			break;;
-		esac
-	done
-	remoteurl="$remoteurl$sep${url%/}"
-	echo "${is_relative:+${up_path}}${remoteurl#./}"
-}
-
 # Resolve a path to be relative to another path.  This is intended for
 # converting submodule paths when git-submodule is run in a subdirectory
 # and only handles paths where the directory separator is '/'.
@@ -281,7 +208,7 @@ cmd_add()
 		die "$(gettext "Relative path can only be used from the toplevel of the working tree")"
 
 		# dereference source url relative to parent's url
-		realrepo=$(resolve_relative_url "$repo") || exit
+		realrepo=$(git submodule--helper resolve-relative-url "$repo") || exit
 		;;
 	*:*|/*)
 		# absolute url
@@ -485,7 +412,7 @@ cmd_init()
 			# Possibly a url relative to parent
 			case "$url" in
 			./*|../*)
-				url=$(resolve_relative_url "$url") || exit
+				url=$(git submodule--helper resolve-relative-url "$url") || exit
 				;;
 			esac
 			git config submodule."$name".url "$url" ||
@@ -1176,9 +1103,9 @@ cmd_sync()
 			# guarantee a trailing /
 			up_path=${up_path%/}/ &&
 			# path from submodule work tree to submodule origin repo
-			sub_origin_url=$(resolve_relative_url "$url" "$up_path") &&
+			sub_origin_url=$(git submodule--helper resolve-relative-url "$url" "$up_path") &&
 			# path from superproject work tree to submodule origin repo
-			super_config_url=$(resolve_relative_url "$url") || exit
+			super_config_url=$(git submodule--helper resolve-relative-url "$url") || exit
 			;;
 		*)
 			sub_origin_url="$url"
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index 627ef85..8a1579c 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -19,6 +19,13 @@ relative_path() {
 	"test \"\$(test-path-utils relative_path '$1' '$2')\" = '$expected'"
 }
 
+test_submodule_relative_url() {
+	test_expect_success "test_submodule_relative_url: $1 $2 $3 => $4" "
+		actual=\$(git submodule--helper resolve-relative-url-test '$1' '$2' '$3') &&
+		test \"\$actual\" = '$4'
+	"
+}
+
 test_git_path() {
 	test_expect_success "git-path $1 $2 => $3" "
 		$1 git rev-parse --git-path $2 >actual &&
@@ -286,4 +293,39 @@ test_git_path GIT_COMMON_DIR=bar config                   bar/config
 test_git_path GIT_COMMON_DIR=bar packed-refs              bar/packed-refs
 test_git_path GIT_COMMON_DIR=bar shallow                  bar/shallow
 
+test_submodule_relative_url "(null)" "../foo/bar" "../sub/a/b/c" "../foo/sub/a/b/c"
+test_submodule_relative_url "../../../" "../foo/bar" "../sub/a/b/c" "../../../../foo/sub/a/b/c"
+test_submodule_relative_url "(null)" "../foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "../" "../foo/bar" "../submodule" "../../foo/submodule"
+test_submodule_relative_url "(null)" "../foo/submodule" "../submodule" "../foo/submodule"
+test_submodule_relative_url "../" "../foo/submodule" "../submodule" "../../foo/submodule"
+test_submodule_relative_url "(null)" "../foo" "../submodule" "../submodule"
+test_submodule_relative_url "../" "../foo" "../submodule" "../../submodule"
+test_submodule_relative_url "(null)" "./foo/bar" "../submodule" "foo/submodule"
+test_submodule_relative_url "../" "./foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "(null)" "./foo" "../submodule" "submodule"
+test_submodule_relative_url "../" "./foo" "../submodule" "../submodule"
+test_submodule_relative_url "(null)" "//somewhere else/repo" "../subrepo" "//somewhere else/subrepo"
+test_submodule_relative_url "(null)" "/u//trash directory.t7406-submodule-update/subsuper_update_r" "../subsubsuper_update_r" "/u//trash directory.t7406-submodule-update/subsubsuper_update_r"
+test_submodule_relative_url "(null)" "/u//trash directory.t7406-submodule-update/super_update_r2" "../subsuper_update_r" "/u//trash directory.t7406-submodule-update/subsuper_update_r"
+test_submodule_relative_url "(null)" "/u/trash directory.t3600-rm/." "../." "/u/trash directory.t3600-rm/."
+test_submodule_relative_url "(null)" "/u/trash directory.t3600-rm" "./." "/u/trash directory.t3600-rm/."
+test_submodule_relative_url "(null)" "/u/trash directory.t7400-submodule-basic/addtest" "../repo" "/u/trash directory.t7400-submodule-basic/repo"
+test_submodule_relative_url "../" "/u/trash directory.t7400-submodule-basic/addtest" "../repo" "/u/trash directory.t7400-submodule-basic/repo"
+test_submodule_relative_url "(null)" "/u/trash directory.t7400-submodule-basic" "./å äö" "/u/trash directory.t7400-submodule-basic/å äö"
+test_submodule_relative_url "(null)" "/u/trash directory.t7403-submodule-sync/." "../submodule" "/u/trash directory.t7403-submodule-sync/submodule"
+test_submodule_relative_url "(null)" "/u/trash directory.t7407-submodule-foreach/submodule" "../submodule" "/u/trash directory.t7407-submodule-foreach/submodule"
+test_submodule_relative_url "(null)" "/u/trash directory.t7409-submodule-detached-worktree/home2/../remote" "../bundle1" "/u/trash directory.t7409-submodule-detached-worktree/home2/../bundle1"
+test_submodule_relative_url "(null)" "/u/trash directory.t7613-merge-submodule/submodule_update_repo" "./." "/u/trash directory.t7613-merge-submodule/submodule_update_repo/."
+test_submodule_relative_url "(null)" "file:///tmp/repo" "../subrepo" "file:///tmp/subrepo"
+test_submodule_relative_url "(null)" "foo/bar" "../submodule" "foo/submodule"
+test_submodule_relative_url "../" "foo/bar" "../submodule" "../foo/submodule"
+test_submodule_relative_url "(null)" "foo" "../submodule" "submodule"
+test_submodule_relative_url "../" "foo" "../submodule" "../submodule"
+test_submodule_relative_url "(null)" "helper:://hostname/repo" "../subrepo" "helper:://hostname/subrepo"
+test_submodule_relative_url "(null)" "ssh://hostname/repo" "../subrepo" "ssh://hostname/subrepo"
+test_submodule_relative_url "(null)" "ssh://hostname:22/repo" "../subrepo" "ssh://hostname:22/subrepo"
+test_submodule_relative_url "(null)" "user@host:path/to/repo" "../subrepo" "user@host:path/to/subrepo"
+test_submodule_relative_url "(null)" "user@host:repo" "../subrepo" "user@host:subrepo"
+
 test_done
-- 
2.7.0.rc0.44.g6033384.dirty

```

## Stefan Beller, 2016-01-20 02:03

Subject: [PATCHv2 2/2] submodule: port init from shell to C
Message-ID: <1453255396-31942-3-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1453255396-31942-3-git-send-email-sbeller%40google.com
In-Reply-To: <1453255396-31942-1-git-send-email-sbeller@google.com>

```
By having the `init` functionality in C, we can reference it easier
from other parts in the code.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/submodule--helper.c | 115 ++++++++++++++++++++++++++++++++++++++++++--
 git-submodule.sh            |  39 +--------------
 2 files changed, 111 insertions(+), 43 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1484b36..fecc9aa 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -221,6 +221,115 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static int git_submodule_config(const char *var, const char *value, void *cb)
+{
+	return parse_submodule_config_option(var, value);
+}
+
+static void init_submodule(const char *path, const char *prefix, int quiet)
+{
+	const struct submodule *sub;
+	struct strbuf sb = STRBUF_INIT;
+	char *url = NULL;
+	const char *upd = NULL;
+	const char *displaypath = relative_path(xgetcwd(), prefix, &sb);;
+
+	/* Only loads from .gitmodules, no overlay with .git/config */
+	gitmodules_config();
+
+	sub = submodule_from_path(null_sha1, path);
+
+	/*
+	 * Copy url setting when it is not set yet.
+	 * To look up the url in .git/config, we must not fall back to
+	 * .gitmodules, so look it up directly.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.url", sub->name);
+	if (git_config_get_string(sb.buf, &url)) {
+		url = xstrdup(sub->url); // as overlayed by .gitmodules
+
+		if (!url)
+			die(_("No url found for submodule path '%s' in .gitmodules"),
+				displaypath);
+
+		/* Possibly a url relative to parent */
+		if (starts_with_dot_dot_slash(url) ||
+		    starts_with_dot_slash(url)) {
+			char *remoteurl;
+			char *remote = get_default_remote();
+			struct strbuf remotesb = STRBUF_INIT;
+			strbuf_addf(&remotesb, "remote.%s.url", remote);
+			free(remote);
+
+			if (git_config_get_string(remotesb.buf, &remoteurl))
+				/*
+				 * The repository is its own
+				 * authoritative upstream
+				 */
+				remoteurl = xgetcwd();
+			url = relative_url(remoteurl, url, NULL);
+			strbuf_release(&remotesb);
+		}
+
+		if (git_config_set(sb.buf, url))
+			die(_("Failed to register url for submodule path '%s'"),
+			    displaypath);
+		if (!quiet)
+			fprintf(stderr, _("Submodule '%s' (%s) registered for path '%s'\n"),
+				sub->name, url, displaypath);
+		free(url);
+	}
+
+	/* Copy "update" setting when it is not set yet */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.update", sub->name);
+	if (git_config_get_string_const(sb.buf, &upd) && sub->update) {
+		upd = sub->update;
+		if (strcmp(sub->update, "checkout") &&
+		    strcmp(sub->update, "rebase") &&
+		    strcmp(sub->update, "merge") &&
+		    strcmp(sub->update, "none")) {
+			fprintf(stderr, _("warning: unknown update mode '%s' suggested for submodule '%s'\n"),
+				upd, sub->name);
+			upd = "none";
+		}
+		if (git_config_set(sb.buf, upd))
+			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
+	}
+	strbuf_release(&sb);
+}
+
+static int module_init(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	int i;
+
+	struct option module_init_options[] = {
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("alternative anchor for relative paths")),
+		OPT__QUIET(&quiet, "Suppress output for initialzing a submodule"),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper init [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_init_options,
+			     git_submodule_helper_usage, 0);
+
+	if (argc == 0)
+		die(_("Pass at least one submodule"));
+
+	for (i = 0; i < argc; i++)
+		init_submodule(argv[i], prefix, quiet);
+
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -466,11 +575,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int git_submodule_config(const char *var, const char *value, void *cb)
-{
-	return parse_submodule_config_option(var, value);
-}
-
 struct submodule_update_clone {
 	/* states */
 	int count;
@@ -716,6 +820,7 @@ static struct cmd_struct commands[] = {
 	{"update-clone", update_clone},
 	{"resolve-relative-url", resolve_relative_url},
 	{"resolve-relative-url-test", resolve_relative_url_test},
+	{"init", module_init}
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 615ef9b..6fce0dc 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -398,45 +398,8 @@ cmd_init()
 	while read mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode"
-		name=$(git submodule--helper name "$sm_path") || exit
-
-		displaypath=$(relative_path "$sm_path")
-
-		# Copy url setting when it is not set yet
-		if test -z "$(git config "submodule.$name.url")"
-		then
-			url=$(git config -f .gitmodules submodule."$name".url)
-			test -z "$url" &&
-			die "$(eval_gettext "No url found for submodule path '\$displaypath' in .gitmodules")"
-
-			# Possibly a url relative to parent
-			case "$url" in
-			./*|../*)
-				url=$(git submodule--helper resolve-relative-url "$url") || exit
-				;;
-			esac
-			git config submodule."$name".url "$url" ||
-			die "$(eval_gettext "Failed to register url for submodule path '\$displaypath'")"
 
-			say "$(eval_gettext "Submodule '\$name' (\$url) registered for path '\$displaypath'")"
-		fi
-
-		# Copy "update" setting when it is not set yet
-		if upd="$(git config -f .gitmodules submodule."$name".update)" &&
-		   test -n "$upd" &&
-		   test -z "$(git config submodule."$name".update)"
-		then
-			case "$upd" in
-			checkout | rebase | merge | none)
-				;; # known modes of updating
-			*)
-				echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
-				upd=none
-				;;
-			esac
-			git config submodule."$name".update "$upd" ||
-			die "$(eval_gettext "Failed to register update mode for submodule path '\$displaypath'")"
-		fi
+		git submodule--helper init ${GIT_QUIET:+--quiet} "$sm_path" || exit
 	done
 }
 
-- 
2.7.0.rc0.44.g6033384.dirty

```

## Stefan Beller, 2016-01-20 03:24

Subject: [PATCHv3 2/2] submodule: port init from shell to C
Message-ID: <1453260274-31005-1-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1453260274-31005-1-git-send-email-sbeller%40google.com
In-Reply-To: <1453255396-31942-3-git-send-email-sbeller@google.com>

```
By having the `init` functionality in C, we can reference it easier
from other parts in the code.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

I noticed a syntactical mistake in this patch, interdiff to v2:

    diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
    index bcfcbdf..def382e 100644
    --- a/builtin/submodule--helper.c
    +++ b/builtin/submodule--helper.c
    @@ -247,7 +247,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
            strbuf_reset(&sb);
            strbuf_addf(&sb, "submodule.%s.url", sub->name);
            if (git_config_get_string(sb.buf, &url)) {
    -               url = xstrdup(sub->url); // as overlayed by .gitmodules
    +               url = xstrdup(sub->url);




 builtin/submodule--helper.c | 115 ++++++++++++++++++++++++++++++++++++++++++--
 git-submodule.sh            |  39 +--------------
 2 files changed, 111 insertions(+), 43 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1484b36..4684f16 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -221,6 +221,115 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static int git_submodule_config(const char *var, const char *value, void *cb)
+{
+	return parse_submodule_config_option(var, value);
+}
+
+static void init_submodule(const char *path, const char *prefix, int quiet)
+{
+	const struct submodule *sub;
+	struct strbuf sb = STRBUF_INIT;
+	char *url = NULL;
+	const char *upd = NULL;
+	const char *displaypath = relative_path(xgetcwd(), prefix, &sb);;
+
+	/* Only loads from .gitmodules, no overlay with .git/config */
+	gitmodules_config();
+
+	sub = submodule_from_path(null_sha1, path);
+
+	/*
+	 * Copy url setting when it is not set yet.
+	 * To look up the url in .git/config, we must not fall back to
+	 * .gitmodules, so look it up directly.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.url", sub->name);
+	if (git_config_get_string(sb.buf, &url)) {
+		url = xstrdup(sub->url);
+
+		if (!url)
+			die(_("No url found for submodule path '%s' in .gitmodules"),
+				displaypath);
+
+		/* Possibly a url relative to parent */
+		if (starts_with_dot_dot_slash(url) ||
+		    starts_with_dot_slash(url)) {
+			char *remoteurl;
+			char *remote = get_default_remote();
+			struct strbuf remotesb = STRBUF_INIT;
+			strbuf_addf(&remotesb, "remote.%s.url", remote);
+			free(remote);
+
+			if (git_config_get_string(remotesb.buf, &remoteurl))
+				/*
+				 * The repository is its own
+				 * authoritative upstream
+				 */
+				remoteurl = xgetcwd();
+			url = relative_url(remoteurl, url, NULL);
+			strbuf_release(&remotesb);
+		}
+
+		if (git_config_set(sb.buf, url))
+			die(_("Failed to register url for submodule path '%s'"),
+			    displaypath);
+		if (!quiet)
+			fprintf(stderr, _("Submodule '%s' (%s) registered for path '%s'\n"),
+				sub->name, url, displaypath);
+		free(url);
+	}
+
+	/* Copy "update" setting when it is not set yet */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.update", sub->name);
+	if (git_config_get_string_const(sb.buf, &upd) && sub->update) {
+		upd = sub->update;
+		if (strcmp(sub->update, "checkout") &&
+		    strcmp(sub->update, "rebase") &&
+		    strcmp(sub->update, "merge") &&
+		    strcmp(sub->update, "none")) {
+			fprintf(stderr, _("warning: unknown update mode '%s' suggested for submodule '%s'\n"),
+				upd, sub->name);
+			upd = "none";
+		}
+		if (git_config_set(sb.buf, upd))
+			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
+	}
+	strbuf_release(&sb);
+}
+
+static int module_init(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	int i;
+
+	struct option module_init_options[] = {
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("alternative anchor for relative paths")),
+		OPT__QUIET(&quiet, "Suppress output for initialzing a submodule"),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper init [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_init_options,
+			     git_submodule_helper_usage, 0);
+
+	if (argc == 0)
+		die(_("Pass at least one submodule"));
+
+	for (i = 0; i < argc; i++)
+		init_submodule(argv[i], prefix, quiet);
+
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -466,11 +575,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int git_submodule_config(const char *var, const char *value, void *cb)
-{
-	return parse_submodule_config_option(var, value);
-}
-
 struct submodule_update_clone {
 	/* states */
 	int count;
@@ -716,6 +820,7 @@ static struct cmd_struct commands[] = {
 	{"update-clone", update_clone},
 	{"resolve-relative-url", resolve_relative_url},
 	{"resolve-relative-url-test", resolve_relative_url_test},
+	{"init", module_init}
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 615ef9b..6fce0dc 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -398,45 +398,8 @@ cmd_init()
 	while read mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode"
-		name=$(git submodule--helper name "$sm_path") || exit
-
-		displaypath=$(relative_path "$sm_path")
-
-		# Copy url setting when it is not set yet
-		if test -z "$(git config "submodule.$name.url")"
-		then
-			url=$(git config -f .gitmodules submodule."$name".url)
-			test -z "$url" &&
-			die "$(eval_gettext "No url found for submodule path '\$displaypath' in .gitmodules")"
-
-			# Possibly a url relative to parent
-			case "$url" in
-			./*|../*)
-				url=$(git submodule--helper resolve-relative-url "$url") || exit
-				;;
-			esac
-			git config submodule."$name".url "$url" ||
-			die "$(eval_gettext "Failed to register url for submodule path '\$displaypath'")"
 
-			say "$(eval_gettext "Submodule '\$name' (\$url) registered for path '\$displaypath'")"
-		fi
-
-		# Copy "update" setting when it is not set yet
-		if upd="$(git config -f .gitmodules submodule."$name".update)" &&
-		   test -n "$upd" &&
-		   test -z "$(git config submodule."$name".update)"
-		then
-			case "$upd" in
-			checkout | rebase | merge | none)
-				;; # known modes of updating
-			*)
-				echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
-				upd=none
-				;;
-			esac
-			git config submodule."$name".update "$upd" ||
-			die "$(eval_gettext "Failed to register update mode for submodule path '\$displaypath'")"
-		fi
+		git submodule--helper init ${GIT_QUIET:+--quiet} "$sm_path" || exit
 	done
 }
 
-- 
2.7.0.rc0.41.g89994f2.dirty

```

## Junio C Hamano, 2016-01-20 21:01

Subject: Re: [PATCHv3 2/2] submodule: port init from shell to C
Message-ID: <xmqq60yo55jh.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqq60yo55jh.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <1453260274-31005-1-git-send-email-sbeller@google.com>

```
Stefan Beller <sbeller@google.com> writes:

> By having the `init` functionality in C, we can reference it easier
> from other parts in the code.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---

How faithful a conversion is this aiming to be?  For example, one
thing I noticed is that some messages that were originally given
with "say" and sent to the standard output, which is emitted to the
standard error with this rewrite.  I didn't read both patches
carefully, so there may be other discrepancies I didn't spot.

I think you would want to do this in three steps:

 - A faithful rewrite from shell to C;

 - s/printf/fprintf(stderr, / for some messages; and finally

 - Hiding of some messages under --quiet.

in the above order.

Thanks.

>  builtin/submodule--helper.c | 115 ++++++++++++++++++++++++++++++++++++++++++--
>  git-submodule.sh            |  39 +--------------
>  2 files changed, 111 insertions(+), 43 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 1484b36..4684f16 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -221,6 +221,115 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
>  	return 0;
>  }
>  
> +static int git_submodule_config(const char *var, const char *value, void *cb)
> +{
> +	return parse_submodule_config_option(var, value);
> +}
> +
> +static void init_submodule(const char *path, const char *prefix, int quiet)
> +{
> +	const struct submodule *sub;
> +	struct strbuf sb = STRBUF_INIT;
> +	char *url = NULL;
> +	const char *upd = NULL;
> +	const char *displaypath = relative_path(xgetcwd(), prefix, &sb);;
> +
> +	/* Only loads from .gitmodules, no overlay with .git/config */
> +	gitmodules_config();
> +
> +	sub = submodule_from_path(null_sha1, path);
> +
> +	/*
> +	 * Copy url setting when it is not set yet.
> +	 * To look up the url in .git/config, we must not fall back to
> +	 * .gitmodules, so look it up directly.
> +	 */
> +	strbuf_reset(&sb);
> +	strbuf_addf(&sb, "submodule.%s.url", sub->name);
> +	if (git_config_get_string(sb.buf, &url)) {
> +		url = xstrdup(sub->url);
> +
> +		if (!url)
> +			die(_("No url found for submodule path '%s' in .gitmodules"),
> +				displaypath);
> +
> +		/* Possibly a url relative to parent */
> +		if (starts_with_dot_dot_slash(url) ||
> +		    starts_with_dot_slash(url)) {
> +			char *remoteurl;
> +			char *remote = get_default_remote();
> +			struct strbuf remotesb = STRBUF_INIT;
> +			strbuf_addf(&remotesb, "remote.%s.url", remote);
> +			free(remote);
> +
> +			if (git_config_get_string(remotesb.buf, &remoteurl))
> +				/*
> +				 * The repository is its own
> +				 * authoritative upstream
> +				 */
> +				remoteurl = xgetcwd();
> +			url = relative_url(remoteurl, url, NULL);
> +			strbuf_release(&remotesb);
> +		}
> +
> +		if (git_config_set(sb.buf, url))
> +			die(_("Failed to register url for submodule path '%s'"),
> +			    displaypath);
> +		if (!quiet)
> +			fprintf(stderr, _("Submodule '%s' (%s) registered for path '%s'\n"),
> +				sub->name, url, displaypath);
> +		free(url);
> +	}
> +
> +	/* Copy "update" setting when it is not set yet */
> +	strbuf_reset(&sb);
> +	strbuf_addf(&sb, "submodule.%s.update", sub->name);
> +	if (git_config_get_string_const(sb.buf, &upd) && sub->update) {
> +		upd = sub->update;
> +		if (strcmp(sub->update, "checkout") &&
> +		    strcmp(sub->update, "rebase") &&
> +		    strcmp(sub->update, "merge") &&
> +		    strcmp(sub->update, "none")) {
> +			fprintf(stderr, _("warning: unknown update mode '%s' suggested for submodule '%s'\n"),
> +				upd, sub->name);
> +			upd = "none";
> +		}
> +		if (git_config_set(sb.buf, upd))
> +			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
> +	}
> +	strbuf_release(&sb);
> +}
> +
> +static int module_init(int argc, const char **argv, const char *prefix)
> +{
> +	int quiet = 0;
> +	int i;
> +
> +	struct option module_init_options[] = {
> +		OPT_STRING(0, "prefix", &prefix,
> +			   N_("path"),
> +			   N_("alternative anchor for relative paths")),
> +		OPT__QUIET(&quiet, "Suppress output for initialzing a submodule"),
> +		OPT_END()
> +	};
> +
> +	const char *const git_submodule_helper_usage[] = {
> +		N_("git submodule--helper init [<path>]"),
> +		NULL
> +	};
> +
> +	argc = parse_options(argc, argv, prefix, module_init_options,
> +			     git_submodule_helper_usage, 0);
> +
> +	if (argc == 0)
> +		die(_("Pass at least one submodule"));
> +
> +	for (i = 0; i < argc; i++)
> +		init_submodule(argv[i], prefix, quiet);
> +
> +	return 0;
> +}
> +
>  struct module_list {
>  	const struct cache_entry **entries;
>  	int alloc, nr;
> @@ -466,11 +575,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> -static int git_submodule_config(const char *var, const char *value, void *cb)
> -{
> -	return parse_submodule_config_option(var, value);
> -}
> -
>  struct submodule_update_clone {
>  	/* states */
>  	int count;
> @@ -716,6 +820,7 @@ static struct cmd_struct commands[] = {
>  	{"update-clone", update_clone},
>  	{"resolve-relative-url", resolve_relative_url},
>  	{"resolve-relative-url-test", resolve_relative_url_test},
> +	{"init", module_init}
>  };
>  
>  int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
> diff --git a/git-submodule.sh b/git-submodule.sh
> index 615ef9b..6fce0dc 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -398,45 +398,8 @@ cmd_init()
>  	while read mode sha1 stage sm_path
>  	do
>  		die_if_unmatched "$mode"
> -		name=$(git submodule--helper name "$sm_path") || exit
> -
> -		displaypath=$(relative_path "$sm_path")
> -
> -		# Copy url setting when it is not set yet
> -		if test -z "$(git config "submodule.$name.url")"
> -		then
> -			url=$(git config -f .gitmodules submodule."$name".url)
> -			test -z "$url" &&
> -			die "$(eval_gettext "No url found for submodule path '\$displaypath' in .gitmodules")"
> -
> -			# Possibly a url relative to parent
> -			case "$url" in
> -			./*|../*)
> -				url=$(git submodule--helper resolve-relative-url "$url") || exit
> -				;;
> -			esac
> -			git config submodule."$name".url "$url" ||
> -			die "$(eval_gettext "Failed to register url for submodule path '\$displaypath'")"
>  
> -			say "$(eval_gettext "Submodule '\$name' (\$url) registered for path '\$displaypath'")"
> -		fi
> -
> -		# Copy "update" setting when it is not set yet
> -		if upd="$(git config -f .gitmodules submodule."$name".update)" &&
> -		   test -n "$upd" &&
> -		   test -z "$(git config submodule."$name".update)"
> -		then
> -			case "$upd" in
> -			checkout | rebase | merge | none)
> -				;; # known modes of updating
> -			*)
> -				echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
> -				upd=none
> -				;;
> -			esac
> -			git config submodule."$name".update "$upd" ||
> -			die "$(eval_gettext "Failed to register update mode for submodule path '\$displaypath'")"
> -		fi
> +		git submodule--helper init ${GIT_QUIET:+--quiet} "$sm_path" || exit
>  	done
>  }

```

## Stefan Beller, 2016-01-20 22:33

Subject: Re: [PATCHv3 2/2] submodule: port init from shell to C
Message-ID: <CAGZ79kajF9zR_m0+hbvasf+rwQcuDeywCzmdjuT6C4M5MBvmUQ@mail.gmail.com>
URL: https://gitlist.dev/e/CAGZ79kajF9zR_m0%2Bhbvasf%2BrwQcuDeywCzmdjuT6C4M5MBvmUQ%40mail.gmail.com
In-Reply-To: <xmqq60yo55jh.fsf@gitster.mtv.corp.google.com>

```
On Wed, Jan 20, 2016 at 1:01 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Stefan Beller <sbeller@google.com> writes:
>
>> By having the `init` functionality in C, we can reference it easier
>> from other parts in the code.
>>
>> Signed-off-by: Stefan Beller <sbeller@google.com>
>> Signed-off-by: Junio C Hamano <gitster@pobox.com>
>> ---
>
> How faithful a conversion is this aiming to be?  For example, one
> thing I noticed is that some messages that were originally given
> with "say" and sent to the standard output, which is emitted to the
> standard error with this rewrite.  I didn't read both patches
> carefully, so there may be other discrepancies I didn't spot.
>
> I think you would want to do this in three steps:
>
>  - A faithful rewrite from shell to C;
>
>  - s/printf/fprintf(stderr, / for some messages; and finally
>
>  - Hiding of some messages under --quiet.
>
> in the above order.

"say" respects the setting of GIT_QUIET, which is usually set when
--quiet is passed, so I think I want:

-  A faithful rewrite from shell to C including messages respecting
   --quiet, such that the "say" behavior is kept.

- s/printf/fprintf(stderr, / for some messages

and then be done with it.

Thanks,
Stefan


>

```

## Junio C Hamano, 2016-01-20 23:04

Subject: Re: [PATCHv3 2/2] submodule: port init from shell to C
Message-ID: <xmqqvb6n3l9g.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqvb6n3l9g.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <CAGZ79kajF9zR_m0+hbvasf+rwQcuDeywCzmdjuT6C4M5MBvmUQ@mail.gmail.com>

```
Stefan Beller <sbeller@google.com> writes:

> "say" respects the setting of GIT_QUIET, which is usually set when
> --quiet is passed, so I think I want:
>
> -  A faithful rewrite from shell to C including messages respecting
>    --quiet, such that the "say" behavior is kept.
>
> - s/printf/fprintf(stderr, / for some messages

Yup, that is the correct order.  Thanks.

```

## Stefan Beller, 2016-01-21 23:18

Subject: [PATCHv4 2/2] submodule: port init from shell to C
Message-ID: <1453418323-29587-1-git-send-email-sbeller@google.com>
URL: https://gitlist.dev/e/1453418323-29587-1-git-send-email-sbeller%40google.com
In-Reply-To: <1453260274-31005-1-git-send-email-sbeller@google.com>

```
By having the `init` functionality in C, we can reference it easier
from other parts in the code.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

Hi Junio,

please replace the top-most patch of sb/submodule-init with this patch.

This will print to stdout instead of stderr, as it's the most
faithful shell -> translation. The s/printf/fprintf(stderr, / patch
will come with the series that needs the behavior, i.e. as one of the
first patches in the groups series (that is under heavy mental
construction currently).

Thanks,
Stefan

Interdiff to the top of sb/submodule-init (6a514f75c25, submodule: port
init from shell to C, Committed: 2016-01-20 12:55:30):

#        diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
#        index 4684f16..6323048 100644
#        --- a/builtin/submodule--helper.c
#        +++ b/builtin/submodule--helper.c
#        @@ -232,7 +232,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
#                struct strbuf sb = STRBUF_INIT;
#                char *url = NULL;
#                const char *upd = NULL;
#        -       const char *displaypath = relative_path(xgetcwd(), prefix, &sb);;
#        +       const char *displaypath = relative_path(xgetcwd(), prefix, &sb);
#         
#                /* Only loads from .gitmodules, no overlay with .git/config */
#                gitmodules_config();
#        @@ -276,7 +276,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
#                                die(_("Failed to register url for submodule path '%s'"),
#                                    displaypath);
#                        if (!quiet)
#        -                       fprintf(stderr, _("Submodule '%s' (%s) registered for path '%s'\n"),
#        +                       printf(_("Submodule '%s' (%s) registered for path '%s'\n"),
#                                        sub->name, url, displaypath);
#                        free(url);
#                }


 builtin/submodule--helper.c | 115 ++++++++++++++++++++++++++++++++++++++++++--
 git-submodule.sh            |  39 +--------------
 2 files changed, 111 insertions(+), 43 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1484b36..6323048 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -221,6 +221,115 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static int git_submodule_config(const char *var, const char *value, void *cb)
+{
+	return parse_submodule_config_option(var, value);
+}
+
+static void init_submodule(const char *path, const char *prefix, int quiet)
+{
+	const struct submodule *sub;
+	struct strbuf sb = STRBUF_INIT;
+	char *url = NULL;
+	const char *upd = NULL;
+	const char *displaypath = relative_path(xgetcwd(), prefix, &sb);
+
+	/* Only loads from .gitmodules, no overlay with .git/config */
+	gitmodules_config();
+
+	sub = submodule_from_path(null_sha1, path);
+
+	/*
+	 * Copy url setting when it is not set yet.
+	 * To look up the url in .git/config, we must not fall back to
+	 * .gitmodules, so look it up directly.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.url", sub->name);
+	if (git_config_get_string(sb.buf, &url)) {
+		url = xstrdup(sub->url);
+
+		if (!url)
+			die(_("No url found for submodule path '%s' in .gitmodules"),
+				displaypath);
+
+		/* Possibly a url relative to parent */
+		if (starts_with_dot_dot_slash(url) ||
+		    starts_with_dot_slash(url)) {
+			char *remoteurl;
+			char *remote = get_default_remote();
+			struct strbuf remotesb = STRBUF_INIT;
+			strbuf_addf(&remotesb, "remote.%s.url", remote);
+			free(remote);
+
+			if (git_config_get_string(remotesb.buf, &remoteurl))
+				/*
+				 * The repository is its own
+				 * authoritative upstream
+				 */
+				remoteurl = xgetcwd();
+			url = relative_url(remoteurl, url, NULL);
+			strbuf_release(&remotesb);
+		}
+
+		if (git_config_set(sb.buf, url))
+			die(_("Failed to register url for submodule path '%s'"),
+			    displaypath);
+		if (!quiet)
+			printf(_("Submodule '%s' (%s) registered for path '%s'\n"),
+				sub->name, url, displaypath);
+		free(url);
+	}
+
+	/* Copy "update" setting when it is not set yet */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.update", sub->name);
+	if (git_config_get_string_const(sb.buf, &upd) && sub->update) {
+		upd = sub->update;
+		if (strcmp(sub->update, "checkout") &&
+		    strcmp(sub->update, "rebase") &&
+		    strcmp(sub->update, "merge") &&
+		    strcmp(sub->update, "none")) {
+			fprintf(stderr, _("warning: unknown update mode '%s' suggested for submodule '%s'\n"),
+				upd, sub->name);
+			upd = "none";
+		}
+		if (git_config_set(sb.buf, upd))
+			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
+	}
+	strbuf_release(&sb);
+}
+
+static int module_init(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	int i;
+
+	struct option module_init_options[] = {
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("alternative anchor for relative paths")),
+		OPT__QUIET(&quiet, "Suppress output for initialzing a submodule"),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper init [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_init_options,
+			     git_submodule_helper_usage, 0);
+
+	if (argc == 0)
+		die(_("Pass at least one submodule"));
+
+	for (i = 0; i < argc; i++)
+		init_submodule(argv[i], prefix, quiet);
+
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -466,11 +575,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int git_submodule_config(const char *var, const char *value, void *cb)
-{
-	return parse_submodule_config_option(var, value);
-}
-
 struct submodule_update_clone {
 	/* states */
 	int count;
@@ -716,6 +820,7 @@ static struct cmd_struct commands[] = {
 	{"update-clone", update_clone},
 	{"resolve-relative-url", resolve_relative_url},
 	{"resolve-relative-url-test", resolve_relative_url_test},
+	{"init", module_init}
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 615ef9b..6fce0dc 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -398,45 +398,8 @@ cmd_init()
 	while read mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode"
-		name=$(git submodule--helper name "$sm_path") || exit
-
-		displaypath=$(relative_path "$sm_path")
-
-		# Copy url setting when it is not set yet
-		if test -z "$(git config "submodule.$name.url")"
-		then
-			url=$(git config -f .gitmodules submodule."$name".url)
-			test -z "$url" &&
-			die "$(eval_gettext "No url found for submodule path '\$displaypath' in .gitmodules")"
-
-			# Possibly a url relative to parent
-			case "$url" in
-			./*|../*)
-				url=$(git submodule--helper resolve-relative-url "$url") || exit
-				;;
-			esac
-			git config submodule."$name".url "$url" ||
-			die "$(eval_gettext "Failed to register url for submodule path '\$displaypath'")"
 
-			say "$(eval_gettext "Submodule '\$name' (\$url) registered for path '\$displaypath'")"
-		fi
-
-		# Copy "update" setting when it is not set yet
-		if upd="$(git config -f .gitmodules submodule."$name".update)" &&
-		   test -n "$upd" &&
-		   test -z "$(git config submodule."$name".update)"
-		then
-			case "$upd" in
-			checkout | rebase | merge | none)
-				;; # known modes of updating
-			*)
-				echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
-				upd=none
-				;;
-			esac
-			git config submodule."$name".update "$upd" ||
-			die "$(eval_gettext "Failed to register update mode for submodule path '\$displaypath'")"
-		fi
+		git submodule--helper init ${GIT_QUIET:+--quiet} "$sm_path" || exit
 	done
 }
 
-- 
2.7.0.rc0.41.g89994f2.dirty

```

## Johannes Sixt, 2016-01-22 19:03

Subject: Re: [PATCHv2 1/2] submodule: port resolve_relative_url from shell to C
Message-ID: <56A27D1F.60007@kdbg.org>
URL: https://gitlist.dev/e/56A27D1F.60007%40kdbg.org
In-Reply-To: <1453255396-31942-2-git-send-email-sbeller@google.com>

```
Am 20.01.2016 um 03:03 schrieb Stefan Beller:
> +static char *last_dir_separator(char *str)
> +{
> +	char *p = str + strlen(str);
> +	while (p-- > str)
> +		if (is_dir_sep(*p))
> +			return p;
> +	return NULL;
> +}
> +

I just noticed that we already have this function. Please squash in the
following.

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1484b36..92d7d32 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -51,21 +51,12 @@ static int starts_with_dot_dot_slash(const char *str)
 	return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]);
 }
 
-static char *last_dir_separator(char *str)
-{
-	char *p = str + strlen(str);
-	while (p-- > str)
-		if (is_dir_sep(*p))
-			return p;
-	return NULL;
-}
-
 /*
  * Returns 1 if it was the last chop before ':'.
  */
 static int chop_last_dir(char **remoteurl, int is_relative)
 {
-	char *rfind = last_dir_separator(*remoteurl);
+	char *rfind = find_last_dir_sep(*remoteurl);
 	if (rfind) {
 		*rfind = '\0';
 		return 0;

```

## Stefan Beller, 2016-01-22 20:23

Subject: Re: [PATCHv2 1/2] submodule: port resolve_relative_url from shell to C
Message-ID: <CAGZ79kZ9rEXmtgTpdP5uG46xbxjeboLx3_pdgvspThdebmpyOw@mail.gmail.com>
URL: https://gitlist.dev/e/CAGZ79kZ9rEXmtgTpdP5uG46xbxjeboLx3_pdgvspThdebmpyOw%40mail.gmail.com
In-Reply-To: <56A27D1F.60007@kdbg.org>

```
On Fri, Jan 22, 2016 at 11:03 AM, Johannes Sixt <j6t@kdbg.org> wrote:
> Am 20.01.2016 um 03:03 schrieb Stefan Beller:
>> +static char *last_dir_separator(char *str)
>> +{
>> +     char *p = str + strlen(str);
>> +     while (p-- > str)
>> +             if (is_dir_sep(*p))
>> +                     return p;
>> +     return NULL;
>> +}
>> +
>
> I just noticed that we already have this function. Please squash in the
> following.

thanks for reviewing! squashed.

>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 1484b36..92d7d32 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -51,21 +51,12 @@ static int starts_with_dot_dot_slash(const char *str)
>         return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]);
>  }
>
> -static char *last_dir_separator(char *str)
> -{
> -       char *p = str + strlen(str);
> -       while (p-- > str)
> -               if (is_dir_sep(*p))
> -                       return p;
> -       return NULL;
> -}
> -
>  /*
>   * Returns 1 if it was the last chop before ':'.
>   */
>  static int chop_last_dir(char **remoteurl, int is_relative)
>  {
> -       char *rfind = last_dir_separator(*remoteurl);
> +       char *rfind = find_last_dir_sep(*remoteurl);
>         if (rfind) {
>                 *rfind = '\0';
>                 return 0;
>

```

## Junio C Hamano, 2016-01-22 22:30

Subject: Re: [PATCHv4 2/2] submodule: port init from shell to C
Message-ID: <xmqqoacdtfh3.fsf@gitster.mtv.corp.google.com>
URL: https://gitlist.dev/e/xmqqoacdtfh3.fsf%40gitster.mtv.corp.google.com
In-Reply-To: <1453418323-29587-1-git-send-email-sbeller@google.com>

```
Stefan Beller <sbeller@google.com> writes:

> By having the `init` functionality in C, we can reference it easier
> from other parts in the code.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>
> Hi Junio,
>
> please replace the top-most patch of sb/submodule-init with this patch.

Will do, but it seems that you'd have to be replacing 1/2 as well,
so perhaps send both when that happens?

```

## Stefan Beller, 2016-01-22 22:32

Subject: Re: [PATCHv4 2/2] submodule: port init from shell to C
Message-ID: <CAGZ79ka6YwWpsU1KF9K8VAz=NhOVRJ9uYMAGTArGE7NXfbJ9Ag@mail.gmail.com>
URL: https://gitlist.dev/e/CAGZ79ka6YwWpsU1KF9K8VAz%3DNhOVRJ9uYMAGTArGE7NXfbJ9Ag%40mail.gmail.com
In-Reply-To: <xmqqoacdtfh3.fsf@gitster.mtv.corp.google.com>

```
On Fri, Jan 22, 2016 at 2:30 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Stefan Beller <sbeller@google.com> writes:
>
>> By having the `init` functionality in C, we can reference it easier
>> from other parts in the code.
>>
>> Signed-off-by: Stefan Beller <sbeller@google.com>
>> ---
>>
>> Hi Junio,
>>
>> please replace the top-most patch of sb/submodule-init with this patch.
>
> Will do, but it seems that you'd have to be replacing 1/2 as well,
> so perhaps send both when that happens?

I'll resend the series later tonight indeed, so no need to pickup that patch.


>

```