prevent a crash

Author: razzmatazz

src/CSharpLanguageServer/Roslyn/Solution.fs

@@ -403,8 +403,7 @@ let solutionGetRazorDocumentForUri
     : Async<(Project * Compilation * SyntaxTree) option> =
     async {
         let cshtmlPath = uri |> Uri.toPath
-        let cshtmlDirectory = Path.GetDirectoryName(cshtmlPath)
-        let normalizedTargetDir = Path.GetFullPath(cshtmlDirectory)
+        let normalizedTargetDir = cshtmlPath |> Path.GetDirectoryName |> Path.GetFullPath
 
         let projectForPath =
             solution.Projects
@@ -417,28 +416,31 @@ let solutionGetRazorDocumentForUri
                     StringComparison.OrdinalIgnoreCase
                 ))
 
-        let projectBaseDir = Path.GetDirectoryName(projectForPath.Value.FilePath)
+        match projectForPath with
+        | None -> return None
+        | Some project ->
+            let projectBaseDir = Path.GetDirectoryName(project.FilePath)
 
-        let! compilation = projectForPath.Value.GetCompilationAsync() |> Async.AwaitTask
+            let! compilation = project.GetCompilationAsync() |> Async.AwaitTask
 
-        let mutable cshtmlTree: SyntaxTree option = None
+            let mutable cshtmlTree: SyntaxTree option = None
 
-        let cshtmlPathTranslated =
-            Path.GetRelativePath(projectBaseDir, cshtmlPath)
-            |> _.Replace(".", "_")
-            |> _.Replace(Path.DirectorySeparatorChar, '_')
-            |> (fun s -> s + ".g.cs")
+            let cshtmlPathTranslated =
+                Path.GetRelativePath(projectBaseDir, cshtmlPath)
+                |> _.Replace(".", "_")
+                |> _.Replace(Path.DirectorySeparatorChar, '_')
+                |> (fun s -> s + ".g.cs")
 
-        for tree in compilation.SyntaxTrees do
-            let path = tree.FilePath
+            for tree in compilation.SyntaxTrees do
+                let path = tree.FilePath
 
-            if path.StartsWith(projectBaseDir) then
-                let relativePath = Path.GetRelativePath(projectBaseDir, path)
+                if path.StartsWith(projectBaseDir) then
+                    let relativePath = Path.GetRelativePath(projectBaseDir, path)
 
-                if relativePath.EndsWith(cshtmlPathTranslated) then
-                    cshtmlTree <- Some tree
+                    if relativePath.EndsWith(cshtmlPathTranslated) then
+                        cshtmlTree <- Some tree
 
-        return cshtmlTree |> Option.map (fun cst -> (projectForPath.Value, compilation, cst))
+            return cshtmlTree |> Option.map (fun cst -> (project, compilation, cst))
     }