fix(selection): drop stale selection indices after undo, redo and clear (0.3.5)

.github/workflows/ci.yml

@@ -49,6 +49,9 @@ jobs:
       - name: Run eraser cursor regression test
         run: npm run test:native:eraser-smoke
 
+      - name: Run selection history regression test
+        run: npm run test:native:selection-smoke
+
       - name: Build package artifacts
         run: npm run build
 

CHANGELOG.md

@@ -2,9 +2,13 @@
 
 All notable changes to `@mathnotes/mobile-ink` will be documented here.
 
-## [Unreleased]
+## [0.3.5] - 2026-10-02
 
+- Fixed a crash when deleting a selection after Undo, Redo or Clear. The selection kept stroke indices from before the history change, and deleting it underflowed a `size_t` and aborted the app with an uncaught `std::length_error`.
+- Fixed Delete or Move after Undo acting on strokes the user never selected. Undo, Redo, Clear and loading now drop index-based selection, object-eraser and transform state, and cancel an in-flight selection transform before reverting.
+- iOS hides the selection toolbar after Undo, Redo and Clear, so it no longer offers actions on strokes that are gone.
 - Added unit tests for `normalizePagePayloadForNativeLoad` covering blank, malformed, and valid native-load payloads (#12).
+- Added `npm run test:native:selection-smoke` regression coverage, run in CI.
 
 
 ## [0.3.4] - 2026-08-15

cpp/DrawingSelection.cpp

@@ -128,7 +128,7 @@ void DrawingSelection::deleteSelection(
     size_t newIndex = 0;
 
     std::vector<Stroke> remainingStrokes;
-    remainingStrokes.reserve(strokes.size() - selectedIndices.size());
+    remainingStrokes.reserve(strokes.size() - delta.removedStrokes.size());
 
     for (size_t i = 0; i < strokes.size(); i++) {
         if (selectedIndices.count(i) == 0) {
@@ -154,7 +154,7 @@ void DrawingSelection::deleteSelection(
     strokes = remainingStrokes;
     selectedIndices.clear();
 
-    if (commit) commit(std::move(delta));
+    if (commit && !delta.removedStrokes.empty()) commit(std::move(delta));
 }
 
 void DrawingSelection::copySelection(

cpp/SkiaDrawingEngine.cpp

@@ -684,13 +684,15 @@ void SkiaDrawingEngine::clear() {
     // the one operation that genuinely needs an O(N) snapshot to support
     // undo, but it happens once per clear (not per stroke), so the cost
     // is bounded.
+    cancelSelectionTransform();
     StrokeDelta delta;
     delta.kind = StrokeDelta::Kind::Clear;
     delta.clearedStrokes = strokes_;
     delta.clearedEraserCircles = eraserCircles_;
 
     strokes_.clear();
     eraserCircles_.clear();
+    resetIndexedSelectionState();
     currentPoints_.clear();
     currentPath_.reset();
     clearActiveShapePreview();
@@ -714,10 +716,12 @@ void SkiaDrawingEngine::undo() {
     std::lock_guard<std::recursive_mutex> lock(stateMutex_);
 
     if (undoStack_.empty()) return;
+    cancelSelectionTransform();
     StrokeDelta delta = std::move(undoStack_.back());
     undoStack_.pop_back();
     revertDelta(delta);
     redoStack_.push_back(std::move(delta));
+    resetIndexedSelectionState();
 
     cachedEraserCircleCount_ = 0;
     bakedCircleCount_ = 0;
@@ -731,10 +735,12 @@ void SkiaDrawingEngine::redo() {
     std::lock_guard<std::recursive_mutex> lock(stateMutex_);
 
     if (redoStack_.empty()) return;
+    cancelSelectionTransform();
     StrokeDelta delta = std::move(redoStack_.back());
     redoStack_.pop_back();
     applyDelta(delta);
     undoStack_.push_back(std::move(delta));
+    resetIndexedSelectionState();
 
     cachedEraserCircleCount_ = 0;
     bakedCircleCount_ = 0;
@@ -855,18 +861,11 @@ bool SkiaDrawingEngine::deserializeDrawing(const std::vector<uint8_t>& data) {
         return false;
     }
 
+    cancelSelectionTransform();
     strokes_ = std::move(loadedStrokes);
     eraserCircles_.clear();  // Clear eraser circles when loading
     bakedCircleCount_ = 0;  // No circles to bake
-    selectedIndices_.clear();
-    isDraggingSelection_ = false;
-    hasDragCache_ = false;
-    selectionOffsetX_ = 0.0f;
-    selectionOffsetY_ = 0.0f;
-    dragBackgroundSnapshot_ = nullptr;
-    nonSelectedSnapshot_ = nullptr;
-    selectedSnapshot_ = nullptr;
-    selectionHighlightSnapshot_ = nullptr;
+    resetIndexedSelectionState();
     // Reset history. Loading a serialized notebook is treated as a
     // checkpoint -- the user wouldn't expect to undo past the load.
     undoStack_.clear();

cpp/SkiaDrawingEngine.h

@@ -137,6 +137,10 @@ class SkiaDrawingEngine {
     void commitDelta(StrokeDelta&& delta);
     void applyDelta(const StrokeDelta& delta);   // forward (used by redo)
     void revertDelta(const StrokeDelta& delta);  // backward (used by undo)
+    // Selection and object-eraser state store positions into strokes_. Call
+    // whenever strokes_ is rebuilt or compacted (undo/redo/clear/load/object
+    // erase) so no stale index can address a different or missing stroke.
+    void resetIndexedSelectionState();
 
     // Pixel-eraser accumulator. During an eraser drag (touchBegan eraser
     // -> touchMoved... -> touchEnded), applyPixelEraserAt only collects

cpp/SkiaDrawingEngineEraser.cpp

@@ -31,7 +31,7 @@ void SkiaDrawingEngine::eraseObjects() {
         std::unordered_map<size_t, size_t> oldToNew;
         size_t newIdx = 0;
         std::vector<Stroke> remaining;
-        remaining.reserve(strokes_.size() - indicesToRemove.size());
+        remaining.reserve(strokes_.size() - delta.removedStrokes.size());
 
         for (size_t i = 0; i < strokes_.size(); ++i) {
             if (indicesToRemove.count(i) == 0) {
@@ -49,6 +49,7 @@ void SkiaDrawingEngine::eraseObjects() {
         }
         if (remaining.size() != strokes_.size()) {
             strokes_ = remaining;
+            resetIndexedSelectionState();
             commitDelta(std::move(delta));
             markStrokeCachesDirty();
         }

cpp/SkiaDrawingEngineSelection.cpp

@@ -144,6 +144,18 @@ void SkiaDrawingEngine::clearSelection() {
     }
 }
 
+void SkiaDrawingEngine::resetIndexedSelectionState() {
+    std::lock_guard<std::recursive_mutex> lock(stateMutex_);
+
+    // Transform state is owned by cancelSelectionTransform(), which callers
+    // run before rebuilding strokes_ so its originals restore into place.
+    // clearSelection() is not reused: drag snapshots must be freed even
+    // when the selection is already empty.
+    selectedIndices_.clear();
+    pendingDeleteIndices_.clear();
+    endSelectionDrag();
+}
+
 void SkiaDrawingEngine::deleteSelection() {
     std::lock_guard<std::recursive_mutex> lock(stateMutex_);
 

ios/MobileInkModule/MobileInkCanvasView.swift

@@ -995,25 +995,46 @@ class MobileInkCanvasView: MTKView {
 
     @objc func clear() {
         guard let engine = drawingEngine else { return }
+        let hadSelection = getSelectionCount(engine) > 0
         clearCanvas(engine)
+        endSelectionInteractionAfterHistoryChange(hadSelection: hadSelection)
         requestDisplay()
         onDrawingChange?([:])
     }
 
     @objc func undo() {
         guard let engine = drawingEngine else { return }
+        let hadSelection = getSelectionCount(engine) > 0
         undoStroke(engine)
+        endSelectionInteractionAfterHistoryChange(hadSelection: hadSelection)
         requestDisplay()
         onDrawingChange?([:])
     }
 
     @objc func redo() {
         guard let engine = drawingEngine else { return }
+        let hadSelection = getSelectionCount(engine) > 0
         redoStroke(engine)
+        endSelectionInteractionAfterHistoryChange(hadSelection: hadSelection)
         requestDisplay()
         onDrawingChange?([:])
     }
 
+    /// Undo, redo and clear rebuild the stroke list, so the engine drops its
+    /// selection. Mirror that here: stop any in-flight move/transform and hide
+    /// the selection toolbar so it cannot act on strokes that are gone.
+    /// An in-progress lasso is kept: it selects against the new strokes on
+    /// pen-up.
+    private func endSelectionInteractionAfterHistoryChange(hadSelection: Bool) {
+        isMovingSelection = false
+        isTransformingSelection = false
+        selectionTransformHandleIndex = -1
+        hasSelectionMoveDelta = false
+        if hadSelection {
+            notifySelectionChange()
+        }
+    }
+
     // MARK: - Eraser Cursor
 
     private func setupEraserCursor() {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mathnotes/mobile-ink",
-  "version": "0.3.4",
+  "version": "0.3.5",
   "description": "Production-grade React Native ink engine with native Skia drawing and continuous canvas primitives.",
   "license": "Apache-2.0",
   "author": "BuilderPro LLC",
@@ -42,11 +42,12 @@
     "test:release": "node --test scripts/*.test.mjs",
     "test:native:smoke": "clang++ -std=c++20 scripts/drawing_serialization_smoke.cpp cpp/DrawingTypes.cpp cpp/DrawingSerialization.cpp cpp/ShapeRecognition.cpp -I cpp -I node_modules/@shopify/react-native-skia/cpp/skia -I node_modules/@shopify/react-native-skia/cpp/skia/modules/pathops/include node_modules/@shopify/react-native-skia/libs/apple/libskia.xcframework/macos-arm64_x86_64/libskia.a node_modules/@shopify/react-native-skia/libs/apple/libpathops.xcframework/macos-arm64_x86_64/libpathops.a -framework ApplicationServices -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation -framework QuartzCore -o /tmp/mobile_ink_drawing_serialization_smoke && /tmp/mobile_ink_drawing_serialization_smoke",
     "test:native:eraser-smoke": "clang++ -std=c++20 scripts/eraser_cursor_smoke.cpp cpp/*.cpp -I cpp -I node_modules/@shopify/react-native-skia/cpp/skia -I node_modules/@shopify/react-native-skia/cpp/skia/modules/pathops/include node_modules/@shopify/react-native-skia/libs/apple/libskia.xcframework/macos-arm64_x86_64/libskia.a node_modules/@shopify/react-native-skia/libs/apple/libpathops.xcframework/macos-arm64_x86_64/libpathops.a -framework ApplicationServices -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation -framework QuartzCore -o /tmp/mobile_ink_eraser_cursor_smoke && /tmp/mobile_ink_eraser_cursor_smoke",
+    "test:native:selection-smoke": "clang++ -std=c++20 scripts/selection_history_smoke.cpp cpp/*.cpp -I cpp -I node_modules/@shopify/react-native-skia/cpp/skia -I node_modules/@shopify/react-native-skia/cpp/skia/modules/pathops/include node_modules/@shopify/react-native-skia/libs/apple/libskia.xcframework/macos-arm64_x86_64/libskia.a node_modules/@shopify/react-native-skia/libs/apple/libpathops.xcframework/macos-arm64_x86_64/libpathops.a -framework ApplicationServices -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation -framework QuartzCore -o /tmp/mobile_ink_selection_history_smoke && /tmp/mobile_ink_selection_history_smoke",
     "test:example:typecheck": "npm --prefix example run typecheck",
     "test:example:export:ios": "npm --prefix example run export:ios",
     "test:example:export:android": "npm --prefix example run export:android",
     "pack:dry-run": "npm pack --dry-run",
-    "validate": "npm run typecheck && npm run test && npm run test:release && npm run test:native:smoke && npm run test:native:eraser-smoke && npm run build && npm run pack:dry-run && npm run test:example:typecheck && npm run test:example:export:ios && npm run test:example:export:android",
+    "validate": "npm run typecheck && npm run test && npm run test:release && npm run test:native:smoke && npm run test:native:eraser-smoke && npm run test:native:selection-smoke && npm run build && npm run pack:dry-run && npm run test:example:typecheck && npm run test:example:export:ios && npm run test:example:export:android",
     "prepack": "npm run build"
   },
   "peerDependencies": {