builtin_diff(): read $GIT_DIFF_OPTS closer to use

diff --git a/builtin/commit.c b/builtin/commit.c
index 83233ca1a54aaf1d25c7084df90d5f1fd4f49a24..04f5b98be34ce126d8b61b64bd29af01ddd4a403 100644 (file)
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -346,7 +346,7 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
                if (write_locked_index(&the_index, &index_lock, 0))
                        die(_("unable to create temporary index"));
 
-               old_index_env = getenv(INDEX_ENVIRONMENT);
+               old_index_env = xstrdup_or_null(getenv(INDEX_ENVIRONMENT));
                setenv(INDEX_ENVIRONMENT, get_lock_file_path(&index_lock), 1);
 
                if (interactive_add(argc, argv, prefix, patch_interactive) != 0)
@@ -356,6 +356,7 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
                        setenv(INDEX_ENVIRONMENT, old_index_env, 1);
                else
                        unsetenv(INDEX_ENVIRONMENT);
+               FREE_AND_NULL(old_index_env);
 
                discard_cache();
                read_cache_from(get_lock_file_path(&index_lock));