diff --git a/environment.c b/environment.c
index 4de7b812ad2..565f65293bb 100644
--- a/environment.c
+++ b/environment.c
@@ -124,6 +124,12 @@ static char *expand_namespace(const char *raw_namespace)
 	return strbuf_detach(&buf, NULL);
 }
 
+static char *git_path_from_env(const char *envvar, const char *path)
+{
+	const char *value = getenv(envvar);
+	return value ? xstrdup(value) : git_pathdup("%s", path);
+}
+
 static void setup_git_env(void)
 {
 	const char *gitfile;
@@ -134,15 +140,9 @@ static void setup_git_env(void)
 		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
 	gitfile = read_gitfile(git_dir);
 	git_dir = xstrdup(gitfile ? gitfile : git_dir);
-	git_object_dir = getenv(DB_ENVIRONMENT);
-	if (!git_object_dir)
-		git_object_dir = git_pathdup("objects");
-	git_index_file = getenv(INDEX_ENVIRONMENT);
-	if (!git_index_file)
-		git_index_file = git_pathdup("index");
-	git_graft_file = getenv(GRAFT_ENVIRONMENT);
-	if (!git_graft_file)
-		git_graft_file = git_pathdup("info/grafts");
+	git_object_dir = git_path_from_env(DB_ENVIRONMENT, "objects");
+	git_index_file = git_path_from_env(INDEX_ENVIRONMENT, "index");
+	git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, "info/grafts");
 	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
 		check_replace_refs = 0;
 	namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));