diff --git a/src/buffer/Buffer.zig b/src/buffer/Buffer.zig
index 9e8f09b..3e88dcd 100644
--- a/src/buffer/Buffer.zig
+++ b/src/buffer/Buffer.zig
@@ -1367,6 +1367,10 @@ pub fn mark_clean(self: *Self) void {
     self.last_save = self.root;
 }
 
+pub fn mark_dirty(self: *Self) void {
+    self.last_save = null;
+}
+
 pub fn is_hidden(self: *const Self) bool {
     return self.hidden;
 }