[commit: ghc] wip/remove-cabal-dep: Drop support for single-file style package databases (3bf9cd3)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/remove-cabal-dep
Link       : http://ghc.haskell.org/trac/ghc/changeset/3bf9cd34565428ecf13079daf6a059defc961b84/ghc

>---------------------------------------------------------------

commit 3bf9cd34565428ecf13079daf6a059defc961b84
Author: Duncan Coutts <duncan at well-typed.com>
Date:   Tue Aug 19 13:23:56 2014 +0100

    Drop support for single-file style package databases
    
    Historically the package db format was a single text file in Read/Show
    format containing [InstalledPackageInfo]. For several years now the
    default format has been a directory with one file per package, plus a
    binary cache.
    
    The old format cannot be supported under the new scheme where the
    compiler will not depend on the Cabal library (because it will not
    have access to the InstalledPackageInfo type) so we must drop support.
    It would still technically be possible to support a single text file
    style db (but containing a different type), but there does not seem to
    be any compelling reason to do so.
    
    (Part of preparitory work for removing the compiler's dep on Cabal)


>---------------------------------------------------------------

3bf9cd34565428ecf13079daf6a059defc961b84
 compiler/main/Packages.lhs | 18 +++++++-----------
 utils/ghc-pkg/Main.hs      | 19 +++++++------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/compiler/main/Packages.lhs b/compiler/main/Packages.lhs
index 702c049..8bb56fd 100644
--- a/compiler/main/Packages.lhs
+++ b/compiler/main/Packages.lhs
@@ -74,7 +74,6 @@ import System.Directory
 import System.FilePath as FilePath
 import qualified System.FilePath.Posix as FilePath.Posix
 import Control.Monad
-import Data.Char (isSpace)
 import Data.List as List
 import Data.Map (Map)
 import Data.Monoid hiding ((<>))
@@ -391,16 +390,13 @@ readPackageConfig dflags conf_file = do
 
        else do
             isfile <- doesFileExist conf_file
-            when (not isfile) $
-              throwGhcExceptionIO $ InstallationError $
-                "can't find a package database at " ++ conf_file
-            debugTraceMsg dflags 2 (text "Using package config file:" <+> text conf_file)
-            str <- readFile conf_file
-            case reads str of
-                [(configs, rest)]
-                    | all isSpace rest -> return (map installedPackageInfoToPackageConfig configs)
-                _ -> throwGhcExceptionIO $ InstallationError $
-                        "invalid package database file " ++ conf_file
+            if isfile
+               then throwGhcExceptionIO $ InstallationError $
+                      "ghc no longer supports single-file style package databases (" ++
+                      conf_file ++
+                      ") use 'ghc-pkg init' to create the database with the correct format."
+               else throwGhcExceptionIO $ InstallationError $
+                      "can't find a package database at " ++ conf_file
 
   let
       top_dir = topDir dflags
diff --git a/utils/ghc-pkg/Main.hs b/utils/ghc-pkg/Main.hs
index 554640e..a2239b2 100644
--- a/utils/ghc-pkg/Main.hs
+++ b/utils/ghc-pkg/Main.hs
@@ -46,6 +46,7 @@ import System.Exit ( exitWith, ExitCode(..) )
 import System.Environment ( getArgs, getProgName, getEnv )
 import System.IO
 import System.IO.Error
+import GHC.IO.Exception (IOErrorType(InappropriateType))
 import Data.List
 import Control.Concurrent
 
@@ -672,9 +673,12 @@ readParseDatabase verbosity mb_user_conf use_cache path
   | otherwise
   = do e <- tryIO $ getDirectoryContents path
        case e of
-         Left _   -> do
-              pkgs <- parseMultiPackageConf verbosity path
-              mkPackageDB pkgs
+         Left err
+           | ioeGetErrorType err == InappropriateType ->
+              die ("ghc no longer supports single-file style package databases ("
+                ++ path ++ ") use 'ghc-pkg init' to create the database with "
+                ++ "the correct format.")
+           | otherwise -> ioError err
          Right fs
            | not use_cache -> ignore_cache (const $ return ())
            | otherwise -> do
@@ -742,15 +746,6 @@ myReadBinPackageDB filepath = do
   hClose h
   return $ Bin.runGet Bin.get b
   
-parseMultiPackageConf :: Verbosity -> FilePath -> IO [InstalledPackageInfo]
-parseMultiPackageConf verbosity file = do
-  when (verbosity > Normal) $ infoLn ("reading package database: " ++ file)
-  str <- readUTF8File file
-  let pkgs = map convertPackageInfoIn $ read str
-  Exception.evaluate pkgs
-    `catchError` \e->
-       die ("error while parsing " ++ file ++ ": " ++ show e)
-  
 parseSingletonPackageConf :: Verbosity -> FilePath -> IO InstalledPackageInfo
 parseSingletonPackageConf verbosity file = do
   when (verbosity > Normal) $ infoLn ("reading package config: " ++ file)