From a078ea73f07f95b0e55d13b51c104be749d0ed3d Mon Sep 17 00:00:00 2001
From: Daniel Gröber <dxld@darkboxed.org>
Date: Mon, 1 Apr 2019 20:40:05 +0200
Subject: Add ProjLocV1Dir for easier forward porting

---
 lib/Distribution/Helper.hs           | 16 +++++++++-------
 src/CabalHelper/Compiletime/Types.hs | 10 ++++++++--
 tests/GhcSession.hs                  |  2 +-
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/Distribution/Helper.hs b/lib/Distribution/Helper.hs
index d25786c..38f819f 100644
--- a/lib/Distribution/Helper.hs
+++ b/lib/Distribution/Helper.hs
@@ -209,18 +209,20 @@ mkQueryEnv projloc distdir = do
     }
 
 -- | Construct paths to project configuration files given where the project is.
-projConf :: ProjLoc pt -> ProjConf pt
-projConf (ProjLocCabalFile cabal_file) =
-   ProjConfV1 cabal_file
+projConf :: ProjLoc pt -> IO (ProjConf pt)
+projConf (ProjLocV1Dir pkgdir) =
+  ProjConfV1 <$> findCabalFile pkgdir
+projConf (ProjLocV1CabalFile cabal_file) = return $
+  ProjConfV1 cabal_file
 projConf (ProjLocV2Dir projdir_path) =
   projConf $ ProjLocV2File $ projdir_path </> "cabal.project"
-projConf (ProjLocV2File proj_file) =
+projConf (ProjLocV2File proj_file) = return $
   ProjConfV2
     { pcV2CabalProjFile       = proj_file
     , pcV2CabalProjLocalFile  = proj_file <.> "local"
     , pcV2CabalProjFreezeFile = proj_file <.> "freeze"
     }
-projConf (ProjLocStackYaml stack_yaml) =
+projConf (ProjLocStackYaml stack_yaml) = return $
   ProjConfStack
     { pcStackYaml = stack_yaml }
 
@@ -313,7 +315,7 @@ checkUpdateProjInfo
     -> Maybe (ProjInfo pt)
     -> IO (ProjInfo pt)
 checkUpdateProjInfo qe mproj_info = do
-  let proj_conf = projConf (qeProjLoc qe)
+  proj_conf <- projConf (qeProjLoc qe)
   mtime <- getProjConfModTime proj_conf
   case mproj_info of
     Nothing -> reconf proj_conf mtime
@@ -374,7 +376,7 @@ discardInactiveUnitInfos active_units uis0 =
 -- system (@cabal@ or @stack@).
 shallowReconfigureProject :: QueryEnvI c pt -> IO ()
 shallowReconfigureProject QueryEnv
-  { qeProjLoc = ProjLocCabalFile _cabal_file
+  { qeProjLoc = _
   , qeDistDir = DistDirV1 _distdirv1 } =
     return ()
 shallowReconfigureProject QueryEnv
diff --git a/src/CabalHelper/Compiletime/Types.hs b/src/CabalHelper/Compiletime/Types.hs
index 95eea9f..cffa663 100644
--- a/src/CabalHelper/Compiletime/Types.hs
+++ b/src/CabalHelper/Compiletime/Types.hs
@@ -66,7 +66,12 @@ data ProjLoc (pt :: ProjType) where
     -- ending in @.cabal@ existing in the directory. More than one such files
     -- existing is a user error. Note: For this project type the concepts of
     -- project and package coincide.
-    ProjLocCabalFile :: { plCabalFile :: !FilePath } -> ProjLoc 'V1
+    ProjLocV1CabalFile :: { plCabalFile :: !FilePath } -> ProjLoc 'V1
+
+    -- | A @cabal v1-build@ project directory. Same as 'ProjLocV1CabalFile' but
+    -- will search for the cabal file for you. If more than one @.cabal@ file
+    -- exists it will shamelessly throw an obscure exception.
+    ProjLocV1Dir :: { plPackageDir :: !FilePath } -> ProjLoc 'V1
 
     -- | A @cabal v2-build@ project\'s marker file is called
     -- @cabal.project@. This configuration file points to the packages that make
@@ -81,7 +86,8 @@ data ProjLoc (pt :: ProjType) where
 deriving instance Show (ProjLoc pt)
 
 plV1Dir :: ProjLoc 'V1 -> FilePath
-plV1Dir (ProjLocCabalFile cabal_file) = takeDirectory cabal_file
+plV1Dir (ProjLocV1CabalFile cabal_file) = takeDirectory cabal_file
+plV1Dir (ProjLocV1Dir pkgdir) = pkgdir
 
 data DistDir (pt :: ProjType) where
     -- | Build directory for cabal /old-build/ aka. /v1-build/ aka. just
diff --git a/tests/GhcSession.hs b/tests/GhcSession.hs
index 2fda204..91e30aa 100644
--- a/tests/GhcSession.hs
+++ b/tests/GhcSession.hs
@@ -347,7 +347,7 @@ oldBuildProjSetup :: ProjSetup0
 oldBuildProjSetup = ProjSetupDescr "cabal-v1" $ Right $ Ex $ ProjSetupImpl
     { psiProjType  = SV1
     , psiDistDir   = \dir -> DistDirV1 (dir </> "dist")
-    , psiProjLoc   = \(CabalFile cf) _projdir -> ProjLocCabalFile cf
+    , psiProjLoc   = \(CabalFile cf) _projdir -> ProjLocV1CabalFile cf
     , psiConfigure = \dir ->
         runWithCwd dir "cabal" [ "configure" ]
     , psiBuild     = \dir ->
-- 
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