Discard selection history for external edits (#1380)

Author: cyanzhong

MarkEditMac/Sources/Editor/Controllers/EditorViewController.swift

@@ -356,6 +356,12 @@ extension EditorViewController {
         return nil
       }
 
+      // Content was reloaded from disk due to an external edit, discard stale offsets
+      if document?.hasBeenReverted == true {
+        EditorSelectionHistory.discard(for: fileURL)
+        return nil
+      }
+
       // Non-LF files have mismatched lengths due to CodeMirror normalization, skip the check
       let fileSize = textContent.contains("\r") ? nil : textContent.utf16.count
       return EditorSelectionHistory.selectionRange(for: fileURL, fileSize: fileSize)

MarkEditMac/Sources/Editor/EditorSelectionHistory.swift

@@ -37,9 +37,7 @@ enum EditorSelectionHistory {
 
     // Discard if the content length changed, the file was likely externally edited
     if let fileSize, entry.fileSize != fileSize {
-      var current = EditorHistory.selectionRanges
-      current.removeValue(forKey: key)
-      EditorHistory.selectionRanges = current
+      discard(for: fileURL)
       return nil
     }
 
@@ -50,6 +48,18 @@ enum EditorSelectionHistory {
     return entry.selectionRange
   }
 
+  static func discard(for fileURL: URL) {
+    if pendingInfo?.fileURL == fileURL {
+      saveTask?.cancel()
+      saveTask = nil
+      pendingInfo = nil
+    }
+
+    var current = EditorHistory.selectionRanges
+    current.removeValue(forKey: fileURL.cacheKey)
+    EditorHistory.selectionRanges = current
+  }
+
   /// Removes selection entries older than the retention period and enforces a maximum entry limit
   static func purgeStaleEntries() {
     // Flush any pending saves before purging

MarkEditMac/Sources/Editor/Models/EditorDocument.swift

@@ -32,6 +32,10 @@ final class EditorDocument: NSDocument {
     isDraft || fileURL == nil || fileData != nil
   }
 
+  var hasBeenReverted: Bool {
+    Date.now.timeIntervalSince(revertedDate) < 1
+  }
+
   var canUndo: Bool {
     get async {
       if isReadOnlyMode {
@@ -614,10 +618,6 @@ private extension EditorDocument {
     UserDefaults.standard.bool(forKey: NSCloseAlwaysConfirmsChanges)
   }
 
-  var hasBeenReverted: Bool {
-    Date.now.timeIntervalSince(revertedDate) < 1
-  }
-
   var needsFormatting: Bool {
     guard !formatCompleted else {
       return false