fix: Check for a bogus root folder in workspace/didChangeWorkspaceFolders request (#380)

Sometimes, LSP clients can send bogus folders (CWD, or homedir) as part
of added folders in didChangeWorkspaceFolders. Whenever this happens
marksman treats the root as the real root of the project folders and
recursively scans/indexes mardown documents underneath.This is
problematic when such root is a homedir because it makes marksman scan
too much and potentially fail.

Fixes #377
Potentially, addresses #373 too

Author: artempyanykh

Marksman/Folder.fs

@@ -249,6 +249,37 @@ module Folder =
 
     let private ignoreFiles = [ ".ignore"; ".gitignore"; ".hgignore" ]
 
+    let private isRealWorkspaceFolder (root: RootPath) : bool =
+        let root = RootPath.toSystem root
+
+        if Directory.Exists(root) then
+            let markerFiles = [| ".marksman.toml" |]
+            let markerDirs = [| ".git"; ".hg"; ".svn" |]
+
+            let hasMarkerFile () =
+                Array.exists (fun marker -> File.Exists(Path.Join(root, marker))) markerFiles
+
+            let hasMarkerDir () =
+                Array.exists (fun marker -> Directory.Exists(Path.Join(root, marker))) markerDirs
+
+            hasMarkerDir () || hasMarkerFile ()
+        else
+            false
+
+    // Context is in
+    // * https://github.com/helix-editor/helix/issues/4436
+    // * https://github.com/artempyanykh/marksman/discussions/377
+    let checkWorkspaceFolderWithWarn (folderId: FolderId) : bool =
+        if isRealWorkspaceFolder folderId.data then
+            true
+        else
+            logger.warn (
+                Log.setMessage "Workspace folder is bogus"
+                >> Log.addContext "root" folderId.data
+            )
+
+            false
+
     let isSingleFile folder =
         match folder.data with
         | SingleFile _ -> true

Marksman/Folder.fsi

@@ -24,6 +24,7 @@ module Folder =
     val docs: Folder -> seq<Doc>
     val docCount: Folder -> int
 
+    val checkWorkspaceFolderWithWarn: FolderId -> bool
     val tryLoad: userConfig: option<Config> -> name: string -> FolderId -> option<Folder>
 
     val singleFile: doc: Doc -> config: option<Config> -> Folder

Marksman/Server.fs

@@ -28,41 +28,12 @@ open Newtonsoft.Json.Linq
 module ServerUtil =
     let logger = LogProvider.getLoggerByName "ServerUtil"
 
-    let private isRealWorkspaceFolder (root: RootPath) : bool =
-        let root = RootPath.toSystem root
-
-        if Directory.Exists(root) then
-            let markerFiles = [| ".marksman.toml" |]
-            let markerDirs = [| ".git"; ".hg"; ".svn" |]
-
-            let hasMarkerFile () =
-                Array.exists (fun marker -> File.Exists(Path.Join(root, marker))) markerFiles
-
-            let hasMarkerDir () =
-                Array.exists (fun marker -> Directory.Exists(Path.Join(root, marker))) markerDirs
-
-            hasMarkerDir () || hasMarkerFile ()
-        else
-            false
-
-    // Remove this and related logic when https://github.com/helix-editor/helix/issues/4436 is resolved.
-    let checkWorkspaceFolderWithWarn (folderId: FolderId) : bool =
-        if isRealWorkspaceFolder folderId.data then
-            true
-        else
-            logger.warn (
-                Log.setMessage "Workspace folder is bogus"
-                >> Log.addContext "root" folderId.data
-            )
-
-            false
-
     let extractWorkspaceFolders (par: InitializeParams) : Map<string, FolderId> =
         match par.WorkspaceFolders with
         | Some folders ->
             folders
             |> Array.map (fun { Name = name; Uri = uri } -> name, UriWith.mkRoot uri)
-            |> Array.filter (fun (_, folderId) -> checkWorkspaceFolderWithWarn folderId)
+            |> Array.filter (fun (_, folderId) -> Folder.checkWorkspaceFolderWithWarn folderId)
             |> Map.ofArray
         | _ ->
             let rootUri =
@@ -75,7 +46,7 @@ module ServerUtil =
                 // No folders are configured. The client can still add folders later using a notification.
                 Map.empty
             | Some rootUri ->
-                if checkWorkspaceFolderWithWarn rootUri then
+                if Folder.checkWorkspaceFolderWithWarn rootUri then
                     let rootName = RootPath.filename rootUri.data
 
                     Map.ofList [ rootName, rootUri ]

Marksman/State.fs

@@ -180,7 +180,11 @@ module State =
                 for f in added do
                     let rootUri = UriWith.mkRoot f.Uri
 
-                    let folder = Folder.tryLoad userConfig f.Name rootUri
+                    let folder =
+                        if Folder.checkWorkspaceFolderWithWarn rootUri then
+                            Folder.tryLoad userConfig f.Name rootUri
+                        else
+                            None
 
                     match folder with
                     | Some folder -> yield folder