[GSoC PATCH v4 5/7] repo: add path.grafts with absolute and relative suffixes

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 <[email protected]>
Mentored-by: Lucas Seiki Oshiro <[email protected]>
Signed-off-by: K Jayatheerth <[email protected]>
---
 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 2a15327094..779240109d 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 431a4842d4..adc4a92487 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