From ba35daaa25986ce0e5df97737085c9e2d6174162 Mon Sep 17 00:00:00 2001
From: Mathieu Boespflug <m@tweag.io>
Date: Sat, 4 Jun 2016 23:07:43 +0200
Subject: [PATCH] Split resolvePackage into two functions.

The gruntwork is now done by `packageFromPackageDescription`. The idea
is that if you already have a resolved `GenericPackageDescription`,
i.e. a `PackageDescription`, then you should still be able to get
a `Package` out of it.
---
 src/Stack/Package.hs | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 1720b50907..62b69a3801 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -21,6 +21,7 @@ module Stack.Package
   ,readPackageUnresolved
   ,readPackageUnresolvedBS
   ,resolvePackage
+  ,packageFromPackageDescription
   ,findOrGenerateCabalFile
   ,hpack
   ,Package(..)
@@ -179,6 +180,16 @@ resolvePackage :: PackageConfig
                -> GenericPackageDescription
                -> Package
 resolvePackage packageConfig gpkg =
+    packageFromPackageDescription
+        packageConfig
+        gpkg
+        (resolvePackageDescription packageConfig gpkg)
+
+packageFromPackageDescription :: PackageConfig
+                              -> GenericPackageDescription
+                              -> PackageDescription
+                              -> Package
+packageFromPackageDescription packageConfig gpkg pkg =
     Package
     { packageName = name
     , packageVersion = fromCabalVersion (pkgVersion pkgId)
@@ -210,7 +221,7 @@ resolvePackage packageConfig gpkg =
           False
           (not . null . exposedModules)
           (library pkg)
-    , packageSimpleType = buildType (packageDescription gpkg) == Just Simple
+    , packageSimpleType = buildType pkg == Just Simple
     }
   where
     pkgFiles = GetPackageFiles $
@@ -236,9 +247,8 @@ resolvePackage packageConfig gpkg =
                     hpackExists <- doesFileExist hpackPath
                     return $ if hpackExists then S.singleton hpackPath else S.empty
                 return (componentModules, componentFiles, buildFiles <> dataFiles', warnings)
-    pkgId = package (packageDescription gpkg)
+    pkgId = package pkg
     name = fromCabalPackageName (pkgName pkgId)
-    pkg = resolvePackageDescription packageConfig gpkg
     deps = M.filterWithKey (const . (/= name)) (packageDependencies pkg)
 
 -- | Generate GHC options for the package's components, and a list of