From eef9c14d248d2e3ad696078e8843894dbf8a4b7c Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Sun, 15 Mar 2015 15:29:47 +0200
Subject: [PATCH] Delete libraries when unregistering

Pinging @manny-fp
---
 Stackage/GhcPkg.hs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Stackage/GhcPkg.hs b/Stackage/GhcPkg.hs
index 8f9f9431..27b7f9e1 100644
--- a/Stackage/GhcPkg.hs
+++ b/Stackage/GhcPkg.hs
@@ -85,9 +85,20 @@ unregisterPackage :: (ByteString -> IO ()) -- ^ log func
 unregisterPackage log' onUnregister docDir flags ident@(PackageIdentifier name _) = do
     log' $ "Unregistering " ++ encodeUtf8 (display ident) ++ "\n"
     onUnregister ident
+
+    -- Delete libraries
+    sourceProcessWithConsumer
+        (proc "ghc-pkg" ("describe" : flags ++ [unpack $ display ident]))
+        (CT.decodeUtf8
+         $= CT.lines
+         $= CL.mapMaybe parseLibraryDir
+         $= CL.mapM_ (void . tryIO . removeTree))
+
     void (readProcessWithExitCode
               "ghc-pkg"
               ("unregister": flags ++ ["--force", unpack $ display name])
               "")
 
     void $ tryIO $ removeTree $ docDir </> fpFromText (display ident)
+  where
+    parseLibraryDir = fmap fpFromText . stripPrefix "library-dirs: "