From 8a294a6accb4231fcad2905054ace92964bdce8e Mon Sep 17 00:00:00 2001
From: Joshua Clayton <joshua.clayton@gmail.com>
Date: Sun, 5 Jun 2016 08:09:52 -0400
Subject: [PATCH] Don't cache an empty list of matches

Why?
====

If a list of matches is empty, there's no reason to cache it.
---
 src/Unused/Cache.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Unused/Cache.hs b/src/Unused/Cache.hs
index a0bbc7d..bfdcc4e 100644
--- a/src/Unused/Cache.hs
+++ b/src/Unused/Cache.hs
@@ -16,6 +16,7 @@ cached context f =
     fromCache = maybe (writeCache =<< liftReaderT f) return =<< readCache
 
 writeCache :: ToRecord a => [a] -> ReaderT String IO [a]
+writeCache [] = return []
 writeCache contents = do
     liftReaderT $ createDirectoryIfMissing True cacheDirectory
     fileName <- ask