Update Cabal version, be more resilient about generating Cabal files

Data/Hackage.hs

@@ -266,12 +266,19 @@ createView viewName modifyCabal src sink = withSystemTempDirectory "createview"
         case msrc of
             Nothing -> return mempty
             Just src -> do
+                -- FIXME only create a new file if the old one doesn't exist?
                 orig <- src $$ sinkLazy
                 new <-
                     case parsePackageDescription $ unpack $ decodeUtf8 orig of
                         ParseOk _ gpd -> do
                             gpd' <- modifyCabal name version time gpd
-                            return $ encodeUtf8 $ pack $ showGenericPackageDescription gpd'
+                            let str = showGenericPackageDescription gpd'
+                            -- sanity check
+                            case parsePackageDescription str of
+                                ParseOk _ _ -> return $ encodeUtf8 $ pack str
+                                x -> do
+                                    $logError $ "Created cabal file that could not be parsed: " ++ tshow (x, str)
+                                    return orig
                         _ -> return orig
                 sourceLazy new $$ storeWrite (HackageViewCabal viewName name version)
                 let fp = fpFromString dir </> relfp

stackage-server.cabal

@@ -111,7 +111,8 @@ library
                  , esqueleto
                  , xml-conduit
                  , html-conduit
-                 , Cabal
+                 -- Avoid https://github.com/haskell/cabal/issues/1202
+                 , Cabal >= 1.18
                  , lifted-base
                  , mono-traversable