fix(server): dissolve stack when its non-primary assets are deleted (#29354)

server/src/services/asset.service.spec.ts

@@ -568,6 +568,34 @@ describe(AssetService.name, () => {
       expect(mocks.stack.delete).toHaveBeenCalledWith(asset.stackId);
     });
 
+    it('should delete the stack when a non-primary asset is deleted and only the primary would remain', async () => {
+      const asset = AssetFactory.from().build();
+      const deletionAsset = {
+        ...getForAssetDeletion(asset),
+        stack: { id: newUuid(), primaryAssetId: newUuid(), assets: [{ id: asset.id }] },
+      };
+      mocks.stack.delete.mockResolvedValue();
+      mocks.assetJob.getForAssetDeletion.mockResolvedValue(deletionAsset);
+
+      await sut.handleAssetDeletion({ id: asset.id, deleteOnDisk: true });
+
+      expect(mocks.stack.delete).toHaveBeenCalledWith(deletionAsset.stack.id);
+    });
+
+    it('should keep the stack when a non-primary asset is deleted and the primary plus another asset remain', async () => {
+      const asset = AssetFactory.from().build();
+      const deletionAsset = {
+        ...getForAssetDeletion(asset),
+        stack: { id: newUuid(), primaryAssetId: newUuid(), assets: [{ id: asset.id }, { id: newUuid() }] },
+      };
+      mocks.assetJob.getForAssetDeletion.mockResolvedValue(deletionAsset);
+
+      await sut.handleAssetDeletion({ id: asset.id, deleteOnDisk: true });
+
+      expect(mocks.stack.delete).not.toHaveBeenCalled();
+      expect(mocks.stack.update).not.toHaveBeenCalled();
+    });
+
     it('should delete a live photo', async () => {
       const motionAsset = AssetFactory.from({ type: AssetType.Video, visibility: AssetVisibility.Hidden }).build();
       const asset = AssetFactory.create({ livePhotoVideoId: motionAsset.id });

server/src/services/asset.service.ts

@@ -316,18 +316,25 @@ export class AssetService extends BaseService {
       return JobStatus.Failed;
     }
 
-    // replace the parent of the stack children with a new asset
-    if (asset.stack?.primaryAssetId === id) {
-      // this only includes timeline visible assets and excludes the primary asset
-      const stackAssetIds = asset.stack.assets.map((a) => a.id);
-      if (stackAssetIds.length >= 2) {
-        const newPrimaryAssetId = stackAssetIds.find((a) => a !== id)!;
+    if (asset.stack) {
+      // asset.stack.assets only includes timeline visible assets and excludes the primary asset
+      const remainingStackAssetIds = asset.stack.assets.map((a) => a.id).filter((assetId) => assetId !== id);
+
+      // the primary survives unless it is the asset being deleted
+      let remainingCount = remainingStackAssetIds.length;
+      if (asset.stack.primaryAssetId !== id) {
+        remainingCount++;
+      }
+
+      if (remainingCount < 2) {
+        // 0 or 1 asset would remain: dissolve the stack so it does not linger as a single-asset stack
+        await this.stackRepository.delete(asset.stack.id);
+      } else if (asset.stack.primaryAssetId === id) {
+        // the primary is being deleted but others remain: promote a new primary
         await this.stackRepository.update(asset.stack.id, {
           id: asset.stack.id,
-          primaryAssetId: newPrimaryAssetId,
+          primaryAssetId: remainingStackAssetIds[0],
         });
-      } else {
-        await this.stackRepository.delete(asset.stack.id);
       }
     }