fix num_samples in concatDataset

mindspore/dataset/engine/datasets.py

@@ -2438,6 +2438,8 @@ class ConcatDataset(DatasetOp):
         self._sampler = _select_sampler(None, sampler, None, None, None)
         cumulative_samples_nums = 0
         for index, child in enumerate(self.children):
+            if hasattr(child, 'sampler') and child.sampler.get_num_samples() is not None:
+                raise ValueError("The parameter NumSamples of %s is not support to be set!" % (child))
 
             if isinstance(child, BatchDataset):
                 raise TypeError("The parameter %s of concat should't be BatchDataset!" % (child))

tests/ut/data/dataset/test_tf_file_3_images/datasetSchema.json

@@ -1,6 +1,5 @@
 {
   "datasetType": "TF",
-  "numRows": 3,
   "columns": {
     "image": {
         "type": "uint8",

tests/ut/python/dataset/test_paddeddataset.py

@@ -213,6 +213,23 @@ def test_raise_error():
         ds3.use_sampler(testsampler)
         assert excinfo.type == 'ValueError'
 
+def test_imagefolder_error():
+    DATA_DIR = "../data/dataset/testPK/data"
+    data = ds.ImageFolderDataset(DATA_DIR, num_samples=14)
+
+    data1 = [{'image': np.zeros(1, np.uint8), 'label': np.array(0, np.int32)},
+             {'image': np.zeros(2, np.uint8), 'label': np.array(1, np.int32)},
+             {'image': np.zeros(3, np.uint8), 'label': np.array(0, np.int32)},
+             {'image': np.zeros(4, np.uint8), 'label': np.array(1, np.int32)},
+             {'image': np.zeros(5, np.uint8), 'label': np.array(0, np.int32)},
+             {'image': np.zeros(6, np.uint8), 'label': np.array(1, np.int32)}]
+
+    data2 = ds.PaddedDataset(data1)
+    data3 = data + data2
+    with pytest.raises(ValueError) as excinfo:
+        testsampler = ds.DistributedSampler(num_shards=5, shard_id=4, shuffle=False, num_samples=None)
+        data3.use_sampler(testsampler)
+        assert excinfo.type == 'ValueError'
 
 def test_imagefolder_padded():
     DATA_DIR = "../data/dataset/testPK/data"