From 9e6a6b479b8a8367a840d4a11b6a366d33743133 Mon Sep 17 00:00:00 2001
From: Kirill Elagin <kirelagin@gmail.com>
Date: Wed, 18 Jul 2018 20:22:57 +0300
Subject: [PATCH] Generate --subpath for local targets

Some packages may need access to files outside of their subdirectory
(e.g. hpack files may source other hpack files). Therefore it is
important to keep the integrity of the project directory and specify
individual subdirectories by passing `--subpath` to `cabal2nix`.

Since `stack` does not support specifying subdirs for file paths (unlike
git repositories), it is impossible to tell in general where is the root
of the dependency. But we can at least do this for local targets.
---
 src/Stack2nix/External/Stack.hs | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/Stack2nix/External/Stack.hs b/src/Stack2nix/External/Stack.hs
index f4f4d23..c2ec1b1 100644
--- a/src/Stack2nix/External/Stack.hs
+++ b/src/Stack2nix/External/Stack.hs
@@ -20,7 +20,7 @@ import           Distribution.Nixpkgs.Haskell.PackageSourceSpec (loadHackageDB)
 import           Options.Applicative
 import           Path                                           (parseAbsFile)
 import           Stack.Build.Source                             (getGhcOptions, loadSourceMapFull)
-import           Stack.Build.Target                             (NeedTargets (..))
+import           Stack.Build.Target                             (NeedTargets (..), Target)
 import           Stack.Config
 import           Stack.Options.BuildParser
 import           Stack.Options.GlobalParser
@@ -37,7 +37,8 @@ import           Stack.Types.Compiler                           (CVType (..),
 import           Stack.Types.Config
 import           Stack.Types.Config.Build                       (BuildCommand (..))
 import           Stack.Types.Nix
-import           Stack.Types.Package                            (PackageSource (..),
+import           Stack.Types.Package                            (LocalPackage (..),
+                                                                 PackageSource (..),
                                                                  lpLocation,
                                                                  lpPackage,
                                                                  packageName,
@@ -64,6 +65,7 @@ import           Text.PrettyPrint.HughesPJClass                 (Doc)
 data PackageRef
   = HackagePackage PackageIdentifierRevision
   | NonHackagePackage PackageIdentifier (PackageLocation FilePath)
+  | TargetPackage PackageIdentifier FilePath
   deriving (Eq, Show)
 
 genNixFile :: Args -> FilePath -> Maybe String -> Maybe String -> DB.HackageDB -> PackageRef -> IO (Either Doc Derivation)
@@ -80,14 +82,22 @@ genNixFile args baseDir uri argRev hackageDB pkgRef = do
       projRoot <- canonicalizePath $ cwd </> baseDir
       let defDir = baseDir </> makeRelative projRoot path
       cabal2nix args (fromMaybe defDir uri) (pack <$> argRev) (const relPath <$> uri) hackageDB
+    TargetPackage _ident path -> do
+      projRoot <- canonicalizePath $ cwd </> baseDir
+      let relPath = makeRelative projRoot path
+      cabal2nix args baseDir (pack <$> argRev) (Just relPath) hackageDB
 
 -- TODO: remove once we use flags, options
-sourceMapToPackages :: Map PackageName PackageSource -> [PackageRef]
-sourceMapToPackages = map sourceToPackage . M.elems
+sourceMapToPackages :: Map PackageName Target -> Map PackageName PackageSource -> [PackageRef]
+sourceMapToPackages targets = map sourceToPackage . M.toList
   where
-    sourceToPackage :: PackageSource -> PackageRef
-    sourceToPackage (PSIndex _ _flags _options pir) = HackagePackage pir
-    sourceToPackage (PSFiles lp _) =
+    sourceToPackage :: (PackageName, PackageSource) -> PackageRef
+    sourceToPackage (_, (PSIndex _ _flags _options pir)) = HackagePackage pir
+    sourceToPackage (name, (PSFiles lp@(LocalPackage { lpLocation = PLFilePath fp }) _)) | name `M.member` targets =
+      let pkg = lpPackage lp
+          ident = PackageIdentifier (packageName pkg) (packageVersion pkg)
+       in TargetPackage ident fp
+    sourceToPackage (_, (PSFiles lp _)) =
       let pkg = lpPackage lp
           ident = PackageIdentifier (packageName pkg) (packageVersion pkg)
        in NonHackagePackage ident (lpLocation lp)
@@ -102,10 +112,10 @@ planAndGenerate
   -> String
   -> RIO env ()
 planAndGenerate boptsCli baseDir remoteUri args@Args {..} ghcnixversion = do
-  (_targets, _mbp, _locals, _extraToBuild, sourceMap) <- loadSourceMapFull
+  (targets, _mbp, _locals, _extraToBuild, sourceMap) <- loadSourceMapFull
     NeedTargets
     boptsCli
-  let pkgs = sourceMapToPackages sourceMap
+  let pkgs = sourceMapToPackages targets sourceMap
   liftIO $ logDebug args $ "plan:\n" ++ show pkgs
 
   hackageDB <- liftIO $ loadHackageDB Nothing argHackageSnapshot
@@ -138,6 +148,7 @@ addGhcOptions buildConf pkgRef drv =
   pkgName = case pkgRef of
     HackagePackage (PackageIdentifierRevision (PackageIdentifier n _) _) -> n
     NonHackagePackage (PackageIdentifier n _) _                          -> n
+    TargetPackage (PackageIdentifier n _) _                              -> n
 
 runPlan :: FilePath
         -> Maybe String