[PATCH v2 6/8] environment.c: fix incorrect git_graft_file initialization

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

"info/grafts" should be part of the "common repository" when accessed
from a linked checkout (iow $GIT_COMMON_DIR/info/grafts, not
$GIT_DIR/info/grafts).

git_path("info/grafts") returns correctly, even without this fix,
because it detects that $GIT_GRAFT_FILE is not set, so it goes with the
common rule: anything except sparse-checkout in 'info' belongs to common
repo. But get_graft_file() would return a wrong value and that one is
used for setting grafts up.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 environment.c          |  2 +-
 t/t0060-path-utils.sh  |  1 +
 t/t2025-checkout-to.sh | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/environment.c b/environment.c
index 50ed40a..d5b0788 100644
--- a/environment.c
+++ b/environment.c
@@ -157,7 +157,7 @@ static void setup_git_env(void)
 					   "objects", &git_db_env);
 	git_index_file = git_path_from_env(INDEX_ENVIRONMENT, git_dir,
 					   "index", &git_index_env);
-	git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, git_dir,
+	git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, git_common_dir,
 					   "info/grafts", &git_graft_env);
 	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
 		check_replace_refs = 0;
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index da82aab..93605f4 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -269,6 +269,7 @@ test_git_path GIT_COMMON_DIR=bar logs/HEAD                .git/logs/HEAD
 test_git_path GIT_COMMON_DIR=bar objects                  bar/objects
 test_git_path GIT_COMMON_DIR=bar objects/bar              bar/objects/bar
 test_git_path GIT_COMMON_DIR=bar info/exclude             bar/info/exclude
+test_git_path GIT_COMMON_DIR=bar info/grafts              bar/info/grafts
 test_git_path GIT_COMMON_DIR=bar info/sparse-checkout     .git/info/sparse-checkout
 test_git_path GIT_COMMON_DIR=bar remotes/bar              bar/remotes/bar
 test_git_path GIT_COMMON_DIR=bar branches/bar             bar/branches/bar
diff --git a/t/t2025-checkout-to.sh b/t/t2025-checkout-to.sh
index 8a00310..508993f 100755
--- a/t/t2025-checkout-to.sh
+++ b/t/t2025-checkout-to.sh
@@ -81,4 +81,22 @@ test_expect_success 'checkout from a bare repo without --to' '
 	)
 '
 
+test_expect_success 'checkout with grafts' '
+	test_when_finished rm .git/info/grafts &&
+	test_commit abc &&
+	SHA1=`git rev-parse HEAD` &&
+	test_commit def &&
+	test_commit xyz &&
+	echo "`git rev-parse HEAD` $SHA1" >.git/info/grafts &&
+	cat >expected <<-\EOF &&
+	xyz
+	abc
+	EOF
+	git log --format=%s -2 >actual &&
+	test_cmp expected actual &&
+	git checkout --detach --to grafted master &&
+	git --git-dir=grafted/.git log --format=%s -2 >actual &&
+	test_cmp expected actual
+'
+
 test_done
-- 
2.1.0.rc0.78.gc0d8480