diff --git a/environment.c b/environment.c
index 42dc3106d2..2986ee7200 100644
--- a/environment.c
+++ b/environment.c
@@ -214,6 +214,8 @@ const char *get_git_dir(void)
 
 const char *get_git_common_dir(void)
 {
+	if (!git_dir)
+		setup_git_env();
 	return git_common_dir;
 }