Fix emptyPathUri (#502)

* Fix emptyPathUri

* Remove platform dependency

Author: cocreature

ghcide.cabal

@@ -245,6 +245,7 @@ test-suite ghcide-tests
         haddock-library,
         haskell-lsp,
         haskell-lsp-types,
+        network-uri,
         lens,
         lsp-test >= 0.8,
         parser-combinators,

src/Development/IDE/Types/Location.hs

@@ -17,6 +17,7 @@ module Development.IDE.Types.Location
     , LSP.NormalizedFilePath
     , fromUri
     , emptyFilePath
+    , emptyPathUri
     , toNormalizedFilePath'
     , LSP.fromNormalizedFilePath
     , filePathToUri'
@@ -53,7 +54,9 @@ uriToFilePath' uri
     | otherwise = LSP.uriToFilePath uri
 
 emptyPathUri :: LSP.NormalizedUri
-emptyPathUri = LSP.NormalizedUri (hash ("" :: String)) ""
+emptyPathUri =
+    let s = "file://"
+    in LSP.NormalizedUri (hash s) s
 
 filePathToUri' :: LSP.NormalizedFilePath -> LSP.NormalizedUri
 filePathToUri' = LSP.normalizedFilePathToUri

test/exe/Main.hs

@@ -31,6 +31,7 @@ import Language.Haskell.LSP.Messages
 import Language.Haskell.LSP.Types
 import Language.Haskell.LSP.Types.Capabilities
 import Language.Haskell.LSP.VFS (applyChange)
+import Network.URI
 import System.Environment.Blank (setEnv)
 import System.FilePath
 import System.IO.Extra
@@ -2110,6 +2111,13 @@ unitTests = do
          uriToFilePath' (fromNormalizedUri $ filePathToUri' "") @?= Just "."
      , testCase "empty file path works using toNormalizedFilePath'" $
          uriToFilePath' (fromNormalizedUri $ filePathToUri' (toNormalizedFilePath' "")) @?= Just ""
+     , testCase "empty path URI" $ do
+         Just URI{..} <- pure $ parseURI (T.unpack $ getUri $ fromNormalizedUri emptyPathUri)
+         uriScheme @?= "file:"
+         uriPath @?= ""
+     , testCase "from empty path URI" $ do
+         let uri = Uri "file://"
+         uriToFilePath' uri @?= Just ""
      ]
 
 -- | Wrapper around 'LSPTest.openDoc'' that sends file creation events