ghc initialization error handling (#609)

There are a couple of cases to handle as seen below.
Thanks @jneira for help discovering them all.
There used to be linking errors but I no longer see those after the multi-cradle patch

Non Nix
=========

The table below shows a couple of combinations of cradles and ghcide versions in a
non-Nix environment. All the version mismatches are now handled as follows:

- "Cannot satisfy package" -  `-package-id` flags referencing
  package versions not available (generally base)
- "bad interface" - tried to load an interface file created by a different version of ghc

cradle/ghcide | 8.6 | 8.8 | 8.10
--------------|-----|----|---
Cabal 8.6   | success | cannot satisfy package | cannot satisfy package
Cabal 8.8   | cannot satisfy package | success | cannot satisfy package
Cabal 8.10  | cannot satisfy package | cannot satisfy package | success
Stack 8.6   | success | bad-interface | bad-interfac-
Stack 8.8   | bad-interface | success | bad-interface
Stack 8.10  | bad-interface | bad-interface | success

Nix
=========

Because Nix redefines the libdir to point at the run-time ghc installation,
it's actually much easier to detect a version mismatch:
just compare the compile-time and run-time libdirs

Author: pepeiborra

exe/Main.hs

@@ -205,7 +205,7 @@ executable ghcide
         directory,
         extra,
         filepath,
-        ghc-check >= 0.3.0.1 && < 0.4,
+        ghc-check >= 0.5.0.1 && < 0.6,
         ghc-paths,
         ghc,
         gitrev,
@@ -215,6 +215,7 @@ executable ghcide
         hie-bios >= 0.5.0 && < 0.6,
         ghcide,
         optparse-applicative,
+        safe-exceptions,
         shake,
         text,
         unordered-containers

ghcide.cabal

@@ -4,7 +4,8 @@
 -- | General utility functions, mostly focused around GHC operations.
 module Development.IDE.GHC.Util(
     -- * HcsEnv and environment
-    HscEnvEq(GhcVersionMismatch, compileTime, runTime), hscEnv, newHscEnvEq,
+    HscEnvEq,
+    hscEnv, newHscEnvEq,
     modifyDynFlags,
     evalGhcEnv,
     runGhcEnv,
@@ -38,7 +39,6 @@ import Fingerprint
 import GhcMonad
 import Control.Exception
 import Data.IORef
-import Data.Version (showVersion, Version)
 import FileCleanup
 import Foreign.Ptr
 import Foreign.ForeignPtr
@@ -170,49 +170,31 @@ data HscEnvEq
                [(InstalledUnitId, DynFlags)] -- In memory components for this HscEnv
                -- This is only used at the moment for the import dirs in
                -- the DynFlags
-    | GhcVersionMismatch { compileTime :: !Version
-                         , runTime     :: !Version
-                         }
 
 -- | Unwrap an 'HsEnvEq'.
 hscEnv :: HscEnvEq -> HscEnv
 hscEnv = either error id . hscEnv'
 
 hscEnv' :: HscEnvEq -> Either String HscEnv
 hscEnv' (HscEnvEq _ x _) = Right x
-hscEnv' GhcVersionMismatch{..} = Left $
-    unwords
-        ["ghcide compiled against GHC"
-        ,showVersion compileTime
-        ,"but currently using"
-        ,showVersion runTime
-        ,". This is unsupported, ghcide must be compiled with the same GHC version as the project."
-        ]
-
 deps :: HscEnvEq -> [(InstalledUnitId, DynFlags)]
 deps (HscEnvEq _ _ u) = u
-deps GhcVersionMismatch{} = []
 
 -- | Wrap an 'HscEnv' into an 'HscEnvEq'.
 newHscEnvEq :: HscEnv -> [(InstalledUnitId, DynFlags)] -> IO HscEnvEq
 newHscEnvEq e uids = do u <- newUnique; return $ HscEnvEq u e uids
 
 instance Show HscEnvEq where
   show (HscEnvEq a _ _) = "HscEnvEq " ++ show (hashUnique a)
-  show GhcVersionMismatch{..} = "GhcVersionMismatch " <> show (compileTime, runTime)
 
 instance Eq HscEnvEq where
   HscEnvEq a _ _ == HscEnvEq b _ _ = a == b
-  GhcVersionMismatch a b == GhcVersionMismatch c d = a == c && b == d
-  _ == _ = False
 
 instance NFData HscEnvEq where
   rnf (HscEnvEq a b c) = rnf (hashUnique a) `seq` b `seq` c `seq` ()
-  rnf GhcVersionMismatch{} = rnf runTime
 
 instance Hashable HscEnvEq where
   hashWithSalt s (HscEnvEq a _b _c) = hashWithSalt s a
-  hashWithSalt salt GhcVersionMismatch{..} = hashWithSalt salt (compileTime, runTime)
 
 -- Fake instance needed to persuade Shake to accept this type as a key.
 -- No harm done as ghcide never persists these keys currently

src/Development/IDE/GHC/Util.hs

@@ -13,7 +13,7 @@ extra-deps:
 - regex-base-0.94.0.0
 - regex-tdfa-1.3.1.0
 - haddock-library-1.8.0
-- ghc-check-0.3.0.1
+- ghc-check-0.5.0.1
 nix:
   packages: [zlib]
 flags:

stack-ghc-lib.yaml

@@ -14,6 +14,6 @@ extra-deps:
 - parser-combinators-1.2.1
 - haddock-library-1.8.0
 - tasty-rerun-1.1.17
-- ghc-check-0.3.0.1
+- ghc-check-0.5.0.1
 nix:
   packages: [zlib]

stack.yaml

@@ -7,7 +7,7 @@ extra-deps:
 - haskell-lsp-0.22.0.0
 - haskell-lsp-types-0.22.0.0
 - lsp-test-0.11.0.1
-- ghc-check-0.3.0.1
+- ghc-check-0.5.0.1
 - hie-bios-0.5.0
 
 # for ghc-8.10

stack810.yaml

@@ -22,7 +22,7 @@ extra-deps:
 - unordered-containers-0.2.10.0
 - file-embed-0.0.11.2
 - heaps-0.3.6.1
-- ghc-check-0.3.0.1
+- ghc-check-0.5.0.1
 # For tasty-retun
 - ansi-terminal-0.10.3
 - ansi-wl-pprint-0.6.9

stack84.yaml

@@ -5,7 +5,8 @@ extra-deps:
 - haskell-lsp-0.22.0.0
 - haskell-lsp-types-0.22.0.0
 - lsp-test-0.11.0.1
-- ghc-check-0.3.0.1
+- ghc-check-0.5.0.1
 - hie-bios-0.5.0
+
 nix:
   packages: [zlib]