From 3d5f08a69d67e7770f0c6e134fe64bcfd7009ff2 Mon Sep 17 00:00:00 2001
From: Daniel Gröber <dxld@darkboxed.org>
Date: Sun, 12 Aug 2018 04:09:03 +0200
Subject: Fix libexec path guessing when using new-build again

---
 lib/Distribution/Helper.hs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/Distribution/Helper.hs b/lib/Distribution/Helper.hs
index 0c2adeb..3a49031 100644
--- a/lib/Distribution/Helper.hs
+++ b/lib/Distribution/Helper.hs
@@ -501,10 +501,11 @@ tryFindCabalHelperTreeDistDir :: IO (Maybe FilePath)
 tryFindCabalHelperTreeDistDir = do
   exe <- canonicalizePath =<< getExecutablePath'
   mplan <- findPlanJson exe
+  let mdistdir = takeDirectory . takeDirectory <$> mplan
   cwd <- getCurrentDirectory
 
   let candidates = sortBy (compare `on` ddType) $ concat
-        [ maybeToList $ DistDir NewBuildDist <$> mplan
+        [ maybeToList $ DistDir NewBuildDist <$> mdistdir
         , [ DistDir OldBuildDist $ (!!3) $ iterate takeDirectory exe ]
         , if takeFileName exe == "ghc" -- we're probably in ghci; try CWD
             then [ DistDir NewBuildDist $ cwd </> "dist-newstyle"
@@ -539,7 +540,10 @@ toOldBuildDistDir (DistDir NewBuildDist dir) = do
     isCabalHelperUnit
       Unit { uPId = PkgId (PkgName n) _
            , uType = UnitTypeLocal
-           } | n == "cabal-helper" = True
+           , uComps
+           } | n == "cabal-helper" &&
+               Map.member (CompNameExe "cabal-helper-wrapper") uComps
+             = True
     isCabalHelperUnit _ = False
 toOldBuildDistDir x = return $ Just x
 
-- 
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