Package keys (for linking/type equality) separated from package IDs.

This patch set makes us no longer assume that a package key is a human
readable string, leaving Cabal free to "do whatever it wants" to allocate
keys; we'll look up the PackageId in the database to display to the user.
This also means we have a new level of qualifier decisions to make at the
package level, and rewriting some Safe Haskell error reporting code to DTRT.

Additionally, we adjust the build system to use a new ghc-cabal output
Make variable PACKAGE_KEY to determine library names and other things,
rather than concatenating PACKAGE/VERSION as before.

Adds a new `-this-package-key` flag to subsume the old, erroneously named
`-package-name` flag, and `-package-key` to select packages by package key.

RFC: The md5 hashes are pretty tough on the eye, as far as the file
system is concerned :(

ToDo: safePkg01 test had its output updated, but the fix is not really right:
the rest of the dependencies are truncated due to the fact the we're only
grepping a single line, but ghc-pkg is wrapping its output.

ToDo: In a later commit, update all submodules to stop using -package-name
and use -this-package-key.  For now, we don't do it to avoid submodule
explosion.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, simonmar, hvr, austin

Subscribers: simonmar, relrod, carter

Differential Revision: https://phabricator.haskell.org/D80

1 files changed, 2 insertions, 2 deletions

diff --git a/testsuite/tests/ghc-api/T7478/T7478.hs b/testsuite/tests/ghc-api/T7478/T7478.hs
index 15c3559f7d..dc6edb21a8 100644
--- a/testsuite/tests/ghc-api/T7478/T7478.hs
+++ b/testsuite/tests/ghc-api/T7478/T7478.hs
@@ -9,7 +9,7 @@ import GHC
 import qualified Config as GHC
 import qualified Outputable as GHC
 import GhcMonad (liftIO)
-import Outputable (PprStyle, qualName, qualModule)
+import Outputable (PprStyle, queryQual)
 
 compileInGhc :: [FilePath]          -- ^ Targets
              -> (String -> IO ())   -- ^ handler for each SevOutput message
@@ -42,7 +42,7 @@ compileInGhc targets handlerOutput = do
         _ -> error "fileFromTarget: not a known target"
 
     collectSrcError handlerOutput flags SevOutput _srcspan style msg
-      = handlerOutput $ GHC.showSDocForUser flags (qualName style,qualModule style) msg
+      = handlerOutput $ GHC.showSDocForUser flags (queryQual style) msg
     collectSrcError _ _ _ _ _ _
       = return ()