Relocatable packages in the same database must share the same prefix

Cabal/Distribution/InstalledPackageInfo.hs

@@ -61,7 +61,8 @@ import Distribution.Text
 import Text.PrettyPrint as Disp
 import qualified Distribution.Compat.ReadP as Parse
 
-import Data.Binary (Binary)
+import Data.Binary  (Binary)
+import Data.Maybe   (fromMaybe)
 import GHC.Generics (Generic)
 
 -- -----------------------------------------------------------------------------
@@ -104,7 +105,8 @@ data InstalledPackageInfo_ m
         frameworkDirs     :: [FilePath],
         frameworks        :: [String],
         haddockInterfaces :: [FilePath],
-        haddockHTMLs      :: [FilePath]
+        haddockHTMLs      :: [FilePath],
+        pkgRoot           :: Maybe FilePath
     }
     deriving (Generic, Read, Show)
 
@@ -155,7 +157,8 @@ emptyInstalledPackageInfo
         frameworkDirs     = [],
         frameworks        = [],
         haddockInterfaces = [],
-        haddockHTMLs      = []
+        haddockHTMLs      = [],
+        pkgRoot           = Nothing
     }
 
 noVersion :: Version
@@ -375,6 +378,9 @@ installedFieldDescrs = [
  , listField   "haddock-html"
         showFilePath       parseFilePathQ
         haddockHTMLs       (\xs pkg -> pkg{haddockHTMLs=xs})
+ , simpleField "pkgroot"
+        (const Disp.empty)        parseFilePathQ
+        (fromMaybe "" . pkgRoot)  (\xs pkg -> pkg{pkgRoot=Just xs})
  ]
 
 deprecatedFieldDescrs :: [FieldDescr InstalledPackageInfo]

Cabal/Distribution/Simple/Configure.hs

@@ -641,7 +641,7 @@ configure (pkg_descr0, pbi) cfg
                     relocatable         = reloc
                   }
 
-        when reloc (checkRelocatable pkg_descr lbi)
+        when reloc (checkRelocatable verbosity pkg_descr lbi)
 
         let dirs = absoluteInstallDirs pkg_descr lbi NoCopyDest
             relative = prefixRelativeInstallDirs (packageId pkg_descr) lbi
@@ -1565,14 +1565,16 @@ checkPackageProblems verbosity gpkg pkg = do
     else die (intercalate "\n\n" errors)
 
 -- | Preform checks if a relocatable build is allowed
-checkRelocatable :: PackageDescription
+checkRelocatable :: Verbosity
+                 -> PackageDescription
                  -> LocalBuildInfo
                  -> IO ()
-checkRelocatable pkg lbi = sequence_ [ checkOS
-                                     , checkCompiler
-                                     , packagePrefixRelative
-                                     , depsPrefixRelative
-                                     ]
+checkRelocatable verbosity pkg lbi
+    = sequence_ [ checkOS
+                , checkCompiler
+                , packagePrefixRelative
+                , depsPrefixRelative
+                ]
   where
     -- Check if the OS support relocatable builds
     checkOS
@@ -1604,17 +1606,22 @@ checkRelocatable pkg lbi = sequence_ [ checkOS
                     [ bindir, libdir, dynlibdir, libexecdir, includedir, datadir
                     , docdir, mandir, htmldir, haddockdir, sysconfdir] )
 
-    -- Check if the library dirs of the dependencies are relative to the
+    -- Check if the library dirs of the dependencies that are in the package
+    -- database to which the package is installed are relative to the
     -- prefix of the package
-    depsPrefixRelative
-        = mapM_ (\l -> when (isNothing $ stripPrefix p l) (die (msg l)))
-                allDepLibDirs
+    depsPrefixRelative = do
+        pkgr <- GHC.pkgRoot verbosity lbi (last (withPackageDB lbi))
+        mapM_ (doCheck pkgr) ipkgs
       where
-        installDirs    = absoluteInstallDirs pkg lbi NoCopyDest
-        p              = prefix installDirs
-        ipkgs          = PackageIndex.allPackages (installedPkgs lbi)
-        allDepLibDirs  = concatMap Installed.libraryDirs ipkgs
-        msg l          = "Library directory of a dependency: " ++ show l ++
-                         "\nis not relative to the installation prefix:\n" ++
-                         show p
-
+        doCheck pkgr ipkg
+          | maybe False (== pkgr) (Installed.pkgRoot ipkg)
+          = mapM_ (\l -> when (isNothing $ stripPrefix p l) (die (msg l)))
+                  (Installed.libraryDirs ipkg)
+          | otherwise
+          = return ()
+        installDirs   = absoluteInstallDirs pkg lbi NoCopyDest
+        p             = prefix installDirs
+        ipkgs         = PackageIndex.allPackages (installedPkgs lbi)
+        msg l         = "Library directory of a dependency: " ++ show l ++
+                        "\nis not relative to the installation prefix:\n" ++
+                        show p

Cabal/Distribution/Simple/GHC/IPI641.hs

@@ -101,5 +101,6 @@ toCurrent ipi@InstalledPackageInfo{} =
     Current.frameworkDirs      = frameworkDirs ipi,
     Current.frameworks         = frameworks ipi,
     Current.haddockInterfaces  = haddockInterfaces ipi,
-    Current.haddockHTMLs       = haddockHTMLs ipi
+    Current.haddockHTMLs       = haddockHTMLs ipi,
+    Current.pkgRoot            = Nothing
   }

Cabal/Distribution/Simple/GHC/IPI642.hs

@@ -136,5 +136,6 @@ toCurrent ipi@InstalledPackageInfo{} =
     Current.frameworkDirs      = frameworkDirs ipi,
     Current.frameworks         = frameworks ipi,
     Current.haddockInterfaces  = haddockInterfaces ipi,
-    Current.haddockHTMLs       = haddockHTMLs ipi
+    Current.haddockHTMLs       = haddockHTMLs ipi,
+    Current.pkgRoot            = Nothing
   }

Cabal/Distribution/Simple/Program/HcPkg.hs

@@ -59,8 +59,6 @@ import Distribution.Compat.Exception
 
 import Data.Char
          ( isSpace )
-import Data.Maybe
-         ( fromMaybe )
 import Data.List
          ( stripPrefix )
 import System.FilePath as FilePath
@@ -162,24 +160,13 @@ dump verbosity hcPkg packagedb = do
       let parsed = map parseInstalledPackageInfo' (splitPkgs str)
        in case [ msg | ParseFailed msg <- parsed ] of
             []   -> Left [   setInstalledPackageId
-                           . maybe id mungePackagePaths pkgroot
+                           . maybe id mungePackagePaths (pkgRoot pkg)
                            $ pkg
-                         | ParseOk _ (pkgroot, pkg) <- parsed ]
+                         | ParseOk _ pkg <- parsed ]
             msgs -> Right msgs
 
     parseInstalledPackageInfo' =
-        parseFieldsFlat fields (Nothing, emptyInstalledPackageInfo)
-      where
-        fields =     liftFieldFst pkgrootField
-               : map liftFieldSnd fieldsInstalledPackageInfo
-
-        pkgrootField =
-          simpleField "pkgroot"
-            showFilePath    parseFilePathQ
-            (fromMaybe "")  (\x _ -> Just x)
-
-        liftFieldFst = liftField fst (\x (_x,y) -> (x,y))
-        liftFieldSnd = liftField snd (\y (x,_y) -> (x,y))
+      parseFieldsFlat fieldsInstalledPackageInfo emptyInstalledPackageInfo
 
     --TODO: this could be a lot faster. We're doing normaliseLineEndings twice
     -- and converting back and forth with lines/unlines.

Cabal/Distribution/Simple/Register.hs

@@ -327,7 +327,8 @@ generalInstalledPackageInfo adjustRelIncDirs pkg ipid lib lbi clbi installDirs =
     IPI.frameworkDirs      = [],
     IPI.frameworks         = frameworks bi,
     IPI.haddockInterfaces  = [haddockdir installDirs </> haddockName pkg],
-    IPI.haddockHTMLs       = [htmldir installDirs]
+    IPI.haddockHTMLs       = [htmldir installDirs],
+    IPI.pkgRoot            = Nothing
   }
   where
     bi = libBuildInfo lib