[commit: ghc] master: Have ghc-pkg use an old-style package key when it's not provided. (5e46e1f)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/5e46e1f5323a7fc09e9bbd9023d5c63e144e1ad3/ghc

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

commit 5e46e1f5323a7fc09e9bbd9023d5c63e144e1ad3
Author: Edward Z. Yang <ezyang at cs.stanford.edu>
Date:   Wed Aug 13 14:04:10 2014 +0100

    Have ghc-pkg use an old-style package key when it's not provided.
    
    Summary:
    When this occurs, it means that the user is using an old version of Cabal.
    In that case, don't barf out: just go ahead and install it as an old-style
    package key.  The user won't be able to link multiple versions together,
    but that should not be a problem because their Cabal can't handle it anyway.
    
    What happens if old-style are mixed up with new-style?  Well, currently
    with Cabal, it's indistinguishable.  However, if at some later point we
    add private dependencies, libraries compiled with old style linker names
    are incompatible with each other.  We'll cross that road when we come
    to it.
    
    Signed-off-by: Edward Z. Yang <ezyang at cs.stanford.edu>
    
    Test Plan: validate
    
    Reviewers: tibbe, hvr, austin
    
    Subscribers: simonmar, relrod, ezyang, carter
    
    Differential Revision: https://phabricator.haskell.org/D154


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

5e46e1f5323a7fc09e9bbd9023d5c63e144e1ad3
 utils/ghc-pkg/Main.hs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/utils/ghc-pkg/Main.hs b/utils/ghc-pkg/Main.hs
index 970ab67..c88b814 100644
--- a/utils/ghc-pkg/Main.hs
+++ b/utils/ghc-pkg/Main.hs
@@ -916,7 +916,7 @@ parsePackageInfo
         -> IO (InstalledPackageInfo, [ValidateWarning])
 parsePackageInfo str =
   case parseInstalledPackageInfo str of
-    ParseOk warnings ok -> return (ok, ws)
+    ParseOk warnings ok -> return (mungePackageInfo ok, ws)
       where
         ws = [ msg | PWarning msg <- warnings
                    , not ("Unrecognized field pkgroot" `isPrefixOf` msg) ]
@@ -924,6 +924,14 @@ parsePackageInfo str =
                            (Nothing, s) -> die s
                            (Just l, s) -> die (show l ++ ": " ++ s)
 
+mungePackageInfo :: InstalledPackageInfo -> InstalledPackageInfo
+mungePackageInfo ipi = ipi { packageKey = packageKey' }
+  where
+    packageKey'
+      | OldPackageKey (PackageIdentifier (PackageName "") _) <- packageKey ipi
+          = OldPackageKey (sourcePackageId ipi)
+      | otherwise = packageKey ipi
+
 -- | Takes the "reexported-modules" field of an InstalledPackageInfo
 -- and resolves the references so they point to the original exporter
 -- of a module (i.e. the module is in exposed-modules, not