Fix keyframe removing (#6494)

Steps to reproduce this bug:

Create a track that starts on the frame i and has keyframe on the frame j (i < j)
Save
Remove the keyframe for the created track on the frame i
Save

CHANGELOG.md

@@ -33,6 +33,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed SAM plugin (403 code for workers in organizations) (<https://github.com/opencv/cvat/pull/6514>)
 - Using initial frame from query parameter to open specific frame in a job
  (<https://github.com/opencv/cvat/pull/6506>)
+- Problem with first keyframe removing (<https://github.com/opencv/cvat/pull/6494>)
 - Server-side validation for attribute specifications
   (<https://github.com/opencv/cvat/pull/6447>)
 - \[API\] File downloading failures for filenames with special characters l(<https://github.com/opencv/cvat/pull/6492>)

cvat/apps/dataset_manager/task.py

@@ -160,6 +160,7 @@ def _add_missing_shape(self, track, first_shape):
             missing_shape = deepcopy(first_shape)
             missing_shape["frame"] = track["frame"]
             missing_shape["outside"] = True
+            missing_shape.pop("id")
             track["shapes"].append(missing_shape)
 
     def _correct_frame_of_tracked_shapes(self, track):

tests/python/rest_api/test_tasks.py

@@ -517,6 +517,22 @@ def test_member_update_task_annotation(
 
         self._test_check_response(is_allow, response, data)
 
+    def test_remove_first_keyframe(self):
+        endpoint = "tasks/8/annotations"
+        shapes0 = [
+            {"type": "rectangle", "frame": 1, "points": [1, 2, 3, 4]},
+            {"type": "rectangle", "frame": 4, "points": [5, 6, 7, 8]},
+        ]
+
+        annotations = {"tracks": [{"label_id": 13, "frame": 0, "shapes": shapes0}]}
+
+        response = patch_method("admin1", endpoint, annotations, action="create")
+        assert response.status_code == HTTPStatus.OK, response.content
+
+        annotations["tracks"][0]["shapes"] = shapes0[1:]
+        response = patch_method("admin1", endpoint, annotations, action="update")
+        assert response.status_code == HTTPStatus.OK
+
 
 @pytest.mark.usefixtures("restore_db_per_class")
 class TestGetTaskDataset: