[PATCH v3 2/7] repo: add path.superproject-working-tree with absolute and relative suffixes

@@ -119,6 +119,16 @@ values that they return:
 `path.gitdir.relative`::
 	The path to the Git repository directory relative to the current working directory.
 
+`path.superproject-working-tree.absolute`::
+	The canonical absolute path to the working tree root of the superproject
+	if the current repository is an initialized submodule. Outputs an empty
+	string if not in a submodule.
+
+`path.superproject-working-tree.relative`::
+	The path to the working tree root of the superproject relative to the
+	current working directory if the current repository is an initialized
+	submodule. Outputs an empty string if not in a submodule.
+
 `path.toplevel.absolute`::
 	The canonical absolute path to the top-level directory of the
 	repository's working tree. Outputs an empty string if the repository

@@ -18,6 +18,7 @@
 #include "strbuf.h"
 #include "string-list.h"
 #include "shallow.h"
+#include "submodule.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "utf8.h"

@@ -121,6 +122,36 @@ static int get_path_gitdir_relative(struct repository *repo, struct strbuf *buf)
 	return 0;
 }
 
+static int get_path_superproject_absolute(struct repository *repo UNUSED, struct strbuf *buf)
+{
+	struct strbuf superproject = STRBUF_INIT;
+
+	if (!get_superproject_working_tree(&superproject)) {
+		strbuf_release(&superproject);
+		strbuf_addstr(buf, "");
+		return 0;
+	}
+
+	format_path(buf, superproject.buf, startup_info->prefix, PATH_FORMAT_CANONICAL);
+	strbuf_release(&superproject);
+	return 0;
+}
+
+static int get_path_superproject_relative(struct repository *repo UNUSED, struct strbuf *buf)
+{
+	struct strbuf superproject = STRBUF_INIT;
+
+	if (!get_superproject_working_tree(&superproject)) {
+		strbuf_release(&superproject);
+		strbuf_addstr(buf, "");
+		return 0;
+	}
+
+	format_path(buf, superproject.buf, startup_info->prefix, PATH_FORMAT_RELATIVE);
+	strbuf_release(&superproject);
+	return 0;
+}
+
 static int get_path_toplevel_absolute(struct repository *repo, struct strbuf *buf)
 {
 	const char *work_tree = repo_get_work_tree(repo);

@@ -163,6 +194,8 @@ static const struct repo_info_field repo_info_field[] = {
 	{ "path.commondir.relative", get_path_commondir_relative },
 	{ "path.gitdir.absolute", get_path_gitdir_absolute },
 	{ "path.gitdir.relative", get_path_gitdir_relative },
+	{ "path.superproject-working-tree.absolute", get_path_superproject_absolute },
+	{ "path.superproject-working-tree.relative", get_path_superproject_relative },
 	{ "path.toplevel.absolute", get_path_toplevel_absolute },
 	{ "path.toplevel.relative", get_path_toplevel_relative },
 	{ "references.format", get_references_format },

@@ -213,6 +213,40 @@ test_repo_info_path 'gitdir with explicit GIT_DIR' 'gitdir' \
 	'.git' \
 	'GIT_DIR="../.git" && export GIT_DIR'
 
+test_expect_success 'path.superproject-working-tree absolute and relative' '
+	test_when_finished "rm -rf sub super" &&
+	git init sub &&
+	test_commit -C sub initial &&
+	git init super &&
+	(
+		cd super &&
+		git -c protocol.file.allow=always submodule add "../sub" sub &&
+		git commit -m "add submodule" &&
+
+		cd sub &&
+		ROOT="$(test-tool path-utils real_path ..)" &&
+
+		echo "path.superproject-working-tree.absolute=$ROOT" >expect.abs &&
+		git repo info path.superproject-working-tree.absolute >actual.abs &&
+		test_cmp expect.abs actual.abs &&
+
+		echo "path.superproject-working-tree.relative=../" >expect.rel &&
+		git repo info path.superproject-working-tree.relative >actual.rel &&
+		test_cmp expect.rel actual.rel
+	)
+'
+
+test_expect_success 'path.superproject-working-tree returns empty when not in a submodule' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		echo "path.superproject-working-tree.absolute=" >expect &&
+		git repo info path.superproject-working-tree.absolute >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_expect_success 'path.toplevel absolute and relative' '
 	test_when_finished "rm -rf repo" &&
 	git init repo &&