[GSoC Patch v6 5/7] repo: add path.grafts with absolute and relative suffixes

[K Jayatheerth <jayatheerthkulkarni2005@gmail.com>]

The repository grafts file specifies alternate parent relationships for
commits and may be used by repository tooling that needs to inspect or
manage grafts. Scripts currently retrieve its location by invoking
`git rev-parse --git-path info/grafts`.

Introduce `path.grafts.absolute` and `path.grafts.relative` keys to
`git repo info`. This exposes the grafts file location as a scriptable
config-like key using standard format rules, allowing scripts to
retrieve it through the same interface as other repository path
information.

Mentored-by: Justin Tobler <jltobler@gmail.com>
Mentored-by: Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>
Signed-off-by: K Jayatheerth <jayatheerthkulkarni2005@gmail.com>
---
 Documentation/git-repo.adoc | 11 +++++++++++
 builtin/repo.c              | 24 ++++++++++++++++++++++++
 t/t1900-repo-info.sh        |  6 ++++++
 3 files changed, 41 insertions(+)

diff --git a/Documentation/git-repo.adoc b/Documentation/git-repo.adoc
index 08ef47750c..868ab0ed9f 100644
--- a/Documentation/git-repo.adoc
+++ b/Documentation/git-repo.adoc
@@ -119,6 +119,17 @@ values that they return:
 `path.gitdir.relative`::
 	The path to the Git repository directory relative to the current working directory.
 
+`path.grafts.absolute`::
+	The canonical absolute path to the repository's graft file.
+	Respects the `GIT_GRAFT_FILE` environment override. The path is
+	returned regardless of whether the file currently exists on disk.
+
+`path.grafts.relative`::
+	The path to the repository's graft file relative to the current
+	working directory. Respects the `GIT_GRAFT_FILE` environment
+	override. The path is returned regardless of whether the file
+	currently exists on disk.
+
 `path.hooks.absolute`::
 	The canonical absolute path to the repository's hooks directory.
 	Respects the `core.hooksPath` configuration. If `core.hooksPath` is
diff --git a/builtin/repo.c b/builtin/repo.c
index 9f1858a127..33f97b03af 100644
--- a/builtin/repo.c
+++ b/builtin/repo.c
@@ -122,6 +122,28 @@ static int get_path_gitdir_relative(struct repository *repo, struct strbuf *buf)
 	return 0;
 }
 
+static int get_path_grafts_absolute(struct repository *repo, struct strbuf *buf)
+{
+	const char *graft_file = repo_get_graft_file(repo);
+
+	if (!graft_file)
+		return error(_("unable to get graft file"));
+
+	format_path(buf, graft_file, "", PATH_FORMAT_CANONICAL);
+	return 0;
+}
+
+static int get_path_grafts_relative(struct repository *repo, struct strbuf *buf)
+{
+	const char *graft_file = repo_get_graft_file(repo);
+
+	if (!graft_file)
+		return error(_("unable to get graft file"));
+
+	format_path(buf, graft_file, repo->prefix, PATH_FORMAT_RELATIVE);
+	return 0;
+}
+
 static int get_path_hooks_absolute(struct repository *repo, struct strbuf *buf)
 {
 	struct strbuf hooks_path = STRBUF_INIT;
@@ -230,6 +252,8 @@ 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.grafts.absolute", get_path_grafts_absolute },
+	{ "path.grafts.relative", get_path_grafts_relative },
 	{ "path.hooks.absolute", get_path_hooks_absolute },
 	{ "path.hooks.relative", get_path_hooks_relative },
 	{ "path.index.absolute", get_path_index_absolute },
diff --git a/t/t1900-repo-info.sh b/t/t1900-repo-info.sh
index 80e025e040..7b0bb0ed42 100755
--- a/t/t1900-repo-info.sh
+++ b/t/t1900-repo-info.sh
@@ -221,6 +221,12 @@ test_repo_info_path 'gitdir with explicit GIT_DIR' 'gitdir' \
 	'.git' \
 	'GIT_DIR="../.git" && export GIT_DIR'
 
+test_repo_info_path 'grafts standard' 'grafts' '.git/info/grafts'
+
+test_repo_info_path 'grafts with GIT_GRAFT_FILE override' 'grafts' \
+	'custom-graft-file' \
+	'GIT_GRAFT_FILE="$ROOT/custom-graft-file" && export GIT_GRAFT_FILE'
+
 test_repo_info_path 'hooks standard' 'hooks' '.git/hooks'
 
 test_repo_info_path 'hooks with core.hooksPath override' 'hooks' \
-- 
2.55.GIT