From a383f4693915f53cd847f0586b1a0fbb4d82b396 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Gr=C3=B6ber?= <dxld@darkboxed.org>
Date: Tue, 18 Aug 2015 04:27:02 +0200
Subject: [PATCH] Fix nasty module graph caching issue

resolvedComponentsCache did not consider outgoing edges in the module
graph when computing the set of dependent files

i.e. for `A -> B, A -> C` `flatten` would give [B,C] instead of [A,B,C]
---
 Language/Haskell/GhcMod/Caching/Types.hs | 2 +-
 Language/Haskell/GhcMod/Target.hs        | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/Language/Haskell/GhcMod/Caching/Types.hs b/Language/Haskell/GhcMod/Caching/Types.hs
index ae32a7c..c4fce4c 100644
--- a/Language/Haskell/GhcMod/Caching/Types.hs
+++ b/Language/Haskell/GhcMod/Caching/Types.hs
@@ -47,6 +47,6 @@ data TimedCacheFiles = TimedCacheFiles {
   -- ^ 'cacheFile' timestamp
   tcFiles     :: [TimedFile]
   -- ^ Timestamped files returned by the cached action
- }
+ } deriving (Eq, Ord, Show)
 
 type ChCacheData = (Programs, FilePath, FilePath, (Version, [Char]))
diff --git a/Language/Haskell/GhcMod/Target.hs b/Language/Haskell/GhcMod/Target.hs
index ffdcd1f..5391f58 100644
--- a/Language/Haskell/GhcMod/Target.hs
+++ b/Language/Haskell/GhcMod/Target.hs
@@ -267,7 +267,8 @@ resolvedComponentsCache = Cached {
            -> [FilePath]
    flatten = Map.elems
       >>> map (gmcHomeModuleGraph >>> gmgGraph
-               >>> Map.elems
+               >>> (Map.keysSet &&& Map.elems)
+               >>> uncurry insert
                >>> map (Set.map mpPath)
                >>> Set.unions
               )