fix pascal_voc import bug

CHANGELOG.md

@@ -60,6 +60,7 @@ non-ascii paths while adding files from "Connected file share" (issue #4428)
 - Extra rerenders of different pages with each click (<https://github.com/opencv/cvat/pull/5178>)
 - Skeleton points exported out of order in the COCO Keypoints format
   (<https://github.com/opencv/cvat/issues/5048>)
+- PASCAL VOC 1.1 can't import dataset (<https://github.com/opencv/cvat/pull/4647>)
 - Changing an object causes current z layer to be set to the maximum (<https://github.com/opencv/cvat/pull/5145>)
 - Job assignee can not resolve an issue (<https://github.com/opencv/cvat/pull/5167>)
 - Create manifest with cvat/server docker container command (<https://github.com/opencv/cvat/pull/5172>)

cvat/apps/dataset_manager/bindings.py

@@ -1863,6 +1863,8 @@ def load_dataset_data(project_annotation, dataset: dm.Dataset, project_data):
     else:
         for label in dataset.categories()[dm.AnnotationType.label].items:
             if not project_annotation.db_project.label_set.filter(name=label.name).exists():
+                if label.name == 'background':
+                    continue
                 raise CvatImportError(f'Target project does not have label with name "{label.name}"')
     for subset_id, subset in enumerate(dataset.subsets().values()):
         job = rq.get_current_job()

tests/python/rest_api/test_projects.py

@@ -475,6 +475,22 @@ def test_can_import_export_dataset_with_imagenet_format(self):
 
         self._test_import_project(username, project_id, format_name, import_data)
 
+    def test_can_import_export_dataset_with_pascal_voc_format(self):
+        username = "admin1"
+        format_name = "PASCAL VOC 1.1"
+        project_id = 4
+
+        response = self._test_export_project(username, project_id, format_name)
+
+        tmp_file = io.BytesIO(response.data)
+        tmp_file.name = "dataset.zip"
+
+        import_data = {
+            "dataset_file": tmp_file,
+        }
+
+        self._test_import_project(username, project_id, format_name, import_data)
+
 
 @pytest.mark.usefixtures("restore_db_per_function")
 class TestPatchProjectLabel: