From 3fd9fae66a353a0f42f9f67d2a5ec8eb081953d0 Mon Sep 17 00:00:00 2001
From: James Hobson <james.hobson@jotron.com>
Date: Wed, 12 Jan 2022 13:31:10 +0100
Subject: [PATCH] Changed to use IO Exceptions

---
 lib/GHCup/Utils.hs | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/lib/GHCup/Utils.hs b/lib/GHCup/Utils.hs
index 555e455..fb6212f 100644
--- a/lib/GHCup/Utils.hs
+++ b/lib/GHCup/Utils.hs
@@ -887,18 +887,19 @@ applyPatches :: (MonadReader env m, HasDirs env, HasLog env, MonadIO m)
              => FilePath   -- ^ dir containing patches
              -> FilePath   -- ^ dir to apply patches in
              -> Excepts '[PatchFailed] m ()
-applyPatches pdir ddir = do 
-  seriesExists <- liftIO (doesFileExist (pdir </> "series"))
-  patches <- if seriesExists
-    then
-      liftIO $ map (pdir </>) . lines <$> readFile (pdir </> "series")
-    else
-      (fmap . fmap) (pdir </>) $ liftIO $ sort <$> findFiles
+applyPatches pdir ddir = do
+  let lexicographical = (fmap . fmap) (pdir </>) $ sort <$> findFiles
         pdir
         (makeRegexOpts compExtended
                        execBlank
                        ([s|.+\.(patch|diff)$|] :: ByteString)
         )
+  let quilt = map (pdir </>) . lines <$> readFile (pdir </> "series")
+
+  patches <- liftIO $ quilt `catchIO` (\e ->
+    if isDoesNotExistError e || isPermissionError e then
+      lexicographical 
+    else throwIO e)
   forM_ patches $ \patch' -> applyPatch patch' ddir