!2380 Fix CocoDataset issue

Merge pull request !2380 from xiefangqi/xfq_fix_coco_issue_01

mindspore/dataset/engine/datasets.py

@@ -996,7 +996,8 @@ class Dataset:
         def get_distribution(output_dataset):
             dev_id = 0
             if isinstance(output_dataset, (Cifar10Dataset, Cifar100Dataset, GeneratorDataset, ImageFolderDatasetV2,
-                                           ManifestDataset, MnistDataset, VOCDataset, CelebADataset, MindDataset)):
+                                           ManifestDataset, MnistDataset, VOCDataset, CocoDataset, CelebADataset,
+                                           MindDataset)):
                 sampler = output_dataset.sampler
                 if isinstance(sampler, samplers.DistributedSampler):
                     dev_id = sampler.shard_id
@@ -4171,8 +4172,8 @@ class CocoDataset(MappableDataset):
         - task='Panoptic', column: [['image', dtype=uint8], ['bbox', dtype=float32], ['category_id', dtype=uint32],
           ['iscrowd', dtype=uint32], ['area', dtype=uint32]].
 
-    This dataset can take in a sampler. sampler and shuffle are mutually exclusive. Table
-    below shows what input args are allowed and their expected behavior.
+    This dataset can take in a sampler. sampler and shuffle are mutually exclusive. CocoDataset doesn't support
+    PKSampler. Table below shows what input args are allowed and their expected behavior.
 
     .. list-table:: Expected Order Behavior of Using 'sampler' and 'shuffle'
        :widths: 25 25 50

mindspore/dataset/engine/validators.py

@@ -397,6 +397,9 @@ def check_cocodataset(method):
 
         check_param_type(nreq_param_bool, param_dict, bool)
 
+        sampler = param_dict.get('sampler')
+        if sampler is not None and isinstance(sampler, samplers.PKSampler):
+            raise ValueError("CocoDataset doesn't support PKSampler")
         check_sampler_shuffle_shard_options(param_dict)
 
         return method(*args, **kwargs)

tests/ut/python/dataset/test_datasets_coco.py

@@ -251,6 +251,16 @@ def test_coco_case_exception():
     except RuntimeError as e:
         assert "json.exception.parse_error" in str(e)
 
+    try:
+        sampler = ds.PKSampler(3)
+        data1 = ds.CocoDataset(DATA_DIR, annotation_file=INVALID_FILE, task="Detection", sampler=sampler)
+        for _ in data1.__iter__():
+            pass
+        assert False
+    except ValueError as e:
+        assert "CocoDataset doesn't support PKSampler" in str(e)
+
+
 if __name__ == '__main__':
     test_coco_detection()
     test_coco_stuff()