fix unicode characters in F# compiler diagnostic messages

src/FsAutoComplete/LspHelpers.fs

@@ -98,6 +98,11 @@ module Conversions =
   let urlForCompilerCode (number: int) =
     $"https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/compiler-messages/fs%04d{number}"
 
+  [<Literal>]
+  let unicodeParagraphCharacter: string = "\u001d"
+
+  let private handleUnicodeParagraph (message: string) = message.Replace(unicodeParagraphCharacter, Environment.NewLine)
+
   let fcsErrorToDiagnostic (error: FSharpDiagnostic) =
     { Range =
         { Start =
@@ -108,7 +113,7 @@ module Conversions =
               Character = error.EndColumn } }
       Severity = fcsSeverityToDiagnostic error.Severity
       Source = Some "F# Compiler"
-      Message = error.Message
+      Message = handleUnicodeParagraph error.Message
       Code = Some(string error.ErrorNumber)
       RelatedInformation = Some [||]
       Tags = None

src/FsAutoComplete/LspHelpers.fsi

@@ -36,6 +36,9 @@ module Conversions =
   val fcsRangeToLspLocation: range: FcsRange -> Location
   val findDeclToLspLocation: decl: FsAutoComplete.FindDeclarationResult -> Location
 
+  [<Literal>]
+  val unicodeParagraphCharacter: string = "\u001d"
+
   type TextDocumentIdentifier with
 
     member GetFilePath: unit -> string

test/FsAutoComplete.Tests.Lsp/CoreTests.fs

@@ -467,3 +467,35 @@ let closeTests state =
           let! diags = doc |> Document.waitForLatestDiagnostics (TimeSpan.FromSeconds 5.0)
           Expect.isNonEmpty diags "There should be no publishDiagnostics without any diags after close"
         }) ])
+
+let diagnosticsTest state =
+  let server =
+    async {
+      printfn "starting..."
+      let path = Path.Combine(__SOURCE_DIRECTORY__, "TestCases", "DiagnosticFormatting")
+      let! (server, events) = serverInitialize path defaultConfigDto state
+      let path = Path.Combine(path, "Program.fs")
+      do! waitForWorkspaceFinishedParsing events
+      return (server, events, path)
+    }
+    |> Async.Cache
+
+  ftestList
+    "Diagnostics formatting Tests"
+    [ testCaseAsync
+        "replacing unicode paragraph by newline"
+        (async {
+          let! (server, events, path) = server
+
+          let tdop: DidOpenTextDocumentParams = { TextDocument = loadDocument path }
+          do! server.TextDocumentDidOpen tdop
+
+          printfn "waiting for compiler..."
+          let! compilerResults = waitForCompilerDiagnosticsForFile "Program.fs" events |> Async.StartChild
+
+          match! compilerResults with
+          | Ok () -> failtest "should get an F# compiler checking error"
+          | Core.Result.Error errors ->
+            Expect.exists errors (fun error -> error.Code = Some "39" || error.Code = Some "41") "should have an error FS0039(identifier not defined) or FS0041(a unique overload for method 'TryParse' could not be determined based on type information prior to this program point)"
+            Expect.all errors (fun error -> not <| error.Message.Contains(unicodeParagraphCharacter)) "message should not contains unicode paragraph characters"
+        }) ]

test/FsAutoComplete.Tests.Lsp/Helpers.fs

@@ -51,11 +51,11 @@ module Expecto =
 
     let testCase = testCaseWithTimeout DEFAULT_TIMEOUT
     let ptestCase = ptestCaseWithTimeout DEFAULT_TIMEOUT
-    let ftestCase = ptestCaseWithTimeout DEFAULT_TIMEOUT
+    let ftestCase = ftestCaseWithTimeout DEFAULT_TIMEOUT
 
     let testCaseAsync = testCaseAsyncWithTimeout DEFAULT_TIMEOUT
     let ptestCaseAsync = ptestCaseAsyncWithTimeout DEFAULT_TIMEOUT
-    let ftestCaseAsync = ptestCaseAsyncWithTimeout DEFAULT_TIMEOUT
+    let ftestCaseAsync = ftestCaseAsyncWithTimeout DEFAULT_TIMEOUT
 
 let rec private copyDirectory sourceDir destDir =
   // Get the subdirectories for the specified directory.

test/FsAutoComplete.Tests.Lsp/Program.fs

@@ -103,6 +103,7 @@ let lspTests =
             UnusedDeclarationsTests.tests createServer
             EmptyFileTests.tests createServer
             CallHierarchy.tests createServer
+            diagnosticsTest createServer
             ] ]
 
 /// Tests that do not require a LSP server

test/FsAutoComplete.Tests.Lsp/TestCases/DiagnosticFormatting/DiagnosticFormatting.fsproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="Test.fs" />
+    <Compile Include="Program.fs" />
+  </ItemGroup>
+
+</Project>

test/FsAutoComplete.Tests.Lsp/TestCases/DiagnosticFormatting/Program.fs

@@ -0,0 +1,9 @@
+// Learn more about F# at http://fsharp.org
+
+open System
+
+[<EntryPoint>]
+let main argv =
+    let isOk, integer = System.Int32.TryParse nope
+    printfn "Hello World from F#!"
+    0 // return an integer exit code