Improve generated edits with CRLF

src/LanguageServer/Text.purs

@@ -3,8 +3,12 @@ module LanguageServer.Text where
 import Prelude
 
 import Data.Array (findIndex, last, length, null, reverse, slice, zip)
+import Data.Either (either)
 import Data.Maybe (Maybe(..))
 import Data.String (Pattern(..), joinWith, split)
+import Data.String.Regex (regex)
+import Data.String.Regex as Regex
+import Data.String.Regex.Flags (noFlags)
 import Data.Tuple (uncurry)
 import LanguageServer.Types (DocumentUri, Position(..), Range(..), TextDocumentEdit(..), TextDocumentIdentifier(..), TextEdit(..), WorkspaceEdit, workspaceEdit)
 
@@ -19,8 +23,9 @@ makeWorkspaceEdit uri version range newText = workspaceEdit [ edit ]
 -- | In particular the scenario of inserting text in the middle AC -> ABC becomes an edit of B only.
 makeMinimalWorkspaceEdit :: DocumentUri -> Number -> String -> String -> Maybe WorkspaceEdit
 makeMinimalWorkspaceEdit uri version oldText newText =
-  let newLines = split (Pattern "\n") newText
-      oldLines = case split (Pattern "\n") oldText of
+  let splitLines t = either (const [t]) (\r -> Regex.split r t) $ regex "\r?\n" noFlags
+      newLines = splitLines newText
+      oldLines = case splitLines oldText of
         -- Add imports adds a newline to the end of the file always, giving bad diffs
         xs | last xs /= Just "" && last newLines == Just "" -> xs <> [""]
         xs -> xs

test/Main.purs

@@ -48,4 +48,13 @@ main = runTest do
       Assert.equal (Just [ mkEdit 0 1 "X\n"]) (getEdit <$> edit)
     test "last line changed" do
       let edit = makeMinimalWorkspaceEdit (DocumentUri "uri") 1.0 "A\nB\nC\n" "A\nB\nX\n"
-      Assert.equal (Just [ mkEdit 2 3 "X\n"]) (getEdit <$> edit)
+      Assert.equal (Just [ mkEdit 2 3 "X\n"]) (getEdit <$> edit)
+
+    test "CRLF" do
+      let edit = makeMinimalWorkspaceEdit (DocumentUri "uri") 1.0 "A\r\nC\r\n" "A\r\nB\r\nC\r\n"
+      Assert.equal (Just [ mkEdit 1 1 "B\n"]) (getEdit <$> edit)
+
+    test "CRLF old-only" do
+      -- If I have a CRLF file for some reason but IDE server gives me back LF
+      let edit = makeMinimalWorkspaceEdit (DocumentUri "uri") 1.0 "A\r\nC\r\n" "A\nB\nC\n"
+      Assert.equal (Just [ mkEdit 1 1 "B\n"]) (getEdit <$> edit)