From dc27ee5083967100c9d4958a2461e63431b4cc45 Mon Sep 17 00:00:00 2001
From: Sebastien Tardif <sebtardif@ncf.ca>
Date: Fri, 17 Jul 2026 11:23:52 -0400
Subject: [PATCH] fix: guard delayed drag autoscroll after dispose

Future.delayed callbacks in selection drag autoscroll can fire after
the editor is removed. The non-null cast on findRenderObject then
crashes. Check mounted and use a safe typed cast before scrolling.
---
 lib/src/_code_selection.dart | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/lib/src/_code_selection.dart b/lib/src/_code_selection.dart
index 6df7f6d..449b308 100644
--- a/lib/src/_code_selection.dart
+++ b/lib/src/_code_selection.dart
@@ -375,11 +375,19 @@ class _CodeSelectionGestureDetectorState extends State<_CodeSelectionGestureDete
   void _autoScrollWhenDragging() {
     final Offset? position = _dragPosition;
     Future.delayed(const Duration(milliseconds: 100), (() {
+      // Widget may have been disposed while the delayed callback was pending.
+      if (!mounted) {
+        return;
+      }
       if (_dragPosition == null || position == null) {
         return;
       }
       if (_dragging) {
-        render.autoScrollWhenDragging(_dragPosition!);
+        final renderObject = widget.editorKey.currentContext?.findRenderObject();
+        if (renderObject is! _CodeFieldRender) {
+          return;
+        }
+        renderObject.autoScrollWhenDragging(_dragPosition!);
         _extendSelection(_dragPosition!, _SelectionChangedCause.drag);
       }
       _autoScrollWhenDragging();
@@ -909,7 +917,12 @@ class _MobileSelectionOverlayController implements _SelectionOverlayController {
       if (!_startHandleDragging) {
         return;
       }
-      ensureRender.autoScrollWhenDragging(_startHandleDragLastPosition);
+      // Overlay/controller may outlive the field after dispose.
+      final renderObject = editorKey.currentContext?.findRenderObject();
+      if (renderObject is! _CodeFieldRender) {
+        return;
+      }
+      renderObject.autoScrollWhenDragging(_startHandleDragLastPosition);
       _handleStartHandleDragUpdate(_startHandleDragLastPosition);
       _autoScrollWhenStartHandleDragging();
     }));
@@ -920,7 +933,11 @@ class _MobileSelectionOverlayController implements _SelectionOverlayController {
       if (!_endHandleDragging) {
         return;
       }
-      ensureRender.autoScrollWhenDragging(_endHandleDragLastPosition);
+      final renderObject = editorKey.currentContext?.findRenderObject();
+      if (renderObject is! _CodeFieldRender) {
+        return;
+      }
+      renderObject.autoScrollWhenDragging(_endHandleDragLastPosition);
       _handleEndHandleDragUpdate(_endHandleDragLastPosition);
       _autoScrollWhenEndHandleDragging();
     }));