Fix issue where modify mode can update the wrong vertex

modules/editable-layers/src/edit-modes/modify-mode.ts

@@ -284,7 +284,7 @@ export class ModifyMode extends GeoJsonEditMode {
 
   handleStopDragging(event: StopDraggingEvent, props: ModeProps<FeatureCollection>) {
     const selectedFeatureIndexes = props.selectedIndexes;
-    const editHandle = getPickedEditHandle(event.picks);
+    const editHandle = getPickedEditHandle(event.pointerDownPicks);
     if (selectedFeatureIndexes.length && editHandle) {
       this._dragEditHandle('finishMovePosition', props, editHandle, event);
     }

modules/editable-layers/test/edit-modes/lib/__snapshots__/modify-mode.spec.ts.snap

@@ -1,5 +1,91 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
+exports[`Correct coordinate edited when stopping near another guide 1`] = `
+{
+  "features": [
+    {
+      "geometry": {
+        "coordinates": [
+          1,
+          2,
+        ],
+        "type": "Point",
+      },
+      "properties": {
+        "editHandleType": "existing",
+        "featureIndex": 0,
+        "guideType": "editHandle",
+        "positionIndexes": [
+          0,
+        ],
+      },
+      "type": "Feature",
+    },
+    {
+      "geometry": {
+        "coordinates": [
+          2,
+          3,
+        ],
+        "type": "Point",
+      },
+      "properties": {
+        "editHandleType": "existing",
+        "featureIndex": 0,
+        "guideType": "editHandle",
+        "positionIndexes": [
+          1,
+        ],
+      },
+      "type": "Feature",
+    },
+    {
+      "geometry": {
+        "coordinates": [
+          3,
+          4,
+        ],
+        "type": "Point",
+      },
+      "properties": {
+        "editHandleType": "existing",
+        "featureIndex": 0,
+        "guideType": "editHandle",
+        "positionIndexes": [
+          2,
+        ],
+      },
+      "type": "Feature",
+    },
+  ],
+  "type": "FeatureCollection",
+}
+`;
+
+exports[`Correct coordinate edited when stopping near another guide 2`] = `
+{
+  "geometry": {
+    "coordinates": [
+      [
+        3.1,
+        4.1,
+      ],
+      [
+        2,
+        3,
+      ],
+      [
+        3,
+        4,
+      ],
+    ],
+    "type": "LineString",
+  },
+  "properties": {},
+  "type": "Feature",
+}
+`;
+
 exports[`Rectangular polygon feature preserves shape 1`] = `
 {
   "features": [

modules/editable-layers/test/edit-modes/lib/modify-mode.spec.ts

@@ -168,7 +168,7 @@ const mockMove = (mode, picks: Pick[], props: ModeProps<FeatureCollection>) => {
   const startDragEvent = createStartDraggingEvent([100, 100], [100, 100], picks);
   mode.handleStartDragging(startDragEvent, props);
 
-  const stopDragEvent = createStopDraggingEvent([110, 115], [100, 100], picks);
+  const stopDragEvent = createStopDraggingEvent([110, 115], [100, 100], picks, picks);
   mode.handleStopDragging(stopDragEvent, props);
 };
 
@@ -199,6 +199,47 @@ test('Rectangular polygon feature preserves shape', () => {
   expect(props.data.features[0]).not.toEqual(movedFeature);
 });
 
+test('Correct coordinate edited when stopping near another guide', () => {
+  const mockOnEdit = vi.fn();
+  const props = createFeatureCollectionProps({
+    data: {
+      type: 'FeatureCollection',
+      features: [lineStringFeature]
+    } as FeatureCollection,
+    selectedIndexes: [0],
+    onEdit: mockOnEdit
+  });
+
+  const mode = new ModifyMode();
+  const guides = mode.getGuides(props);
+  expect(guides).toMatchSnapshot();
+
+  const dragStart = [1, 2];
+  const dragEnd = [3.1, 4.1];
+
+  const pointerDownPicks = [
+    { index: 0, isGuide: true, object: guides.features[0] },
+    { index: 0, object: lineStringFeature }
+  ];
+
+  const stopDragPicks = [
+    { index: 2, isGuide: true, object: guides.features[2] },  // simulate another guide being picked
+    { index: 0, isGuide: true, object: guides.features[0] },
+    { index: 0, object: lineStringFeature }
+  ];
+
+  const startDragEvent = createStartDraggingEvent(dragStart, dragStart, pointerDownPicks);
+  mode.handleStartDragging(startDragEvent, props);
+
+  const stopDragEvent = createStopDraggingEvent(dragEnd, dragStart, stopDragPicks, pointerDownPicks);
+  mode.handleStopDragging(stopDragEvent, props);
+
+  expect(mockOnEdit).toHaveBeenCalledTimes(1);
+
+  const editedFeature = mockOnEdit.mock.calls[0][0].updatedData.features[0];
+  expect(editedFeature).toMatchSnapshot();
+});
+
 describe('getGuides()', () => {
   it('gets edit handles for Point', () => {
     const mode = new ModifyMode();

modules/editable-layers/test/edit-modes/test-utils.ts

@@ -345,15 +345,16 @@ export function createStartDraggingEvent(
 export function createStopDraggingEvent(
   mapCoords: Position,
   pointerDownMapCoords: Position,
-  picks: Pick[] = []
+  picks: Pick[] = [],
+  pointerDownPicks: Pick[] | null = null
 ): StopDraggingEvent {
   lastCoords = mapCoords;
 
   return {
     screenCoords: [-1, -1],
     mapCoords,
     picks,
-    pointerDownPicks: null,
+    pointerDownPicks,
     pointerDownScreenCoords: [-1, -1],
     pointerDownMapCoords,
     sourceEvent: null