Added "allow_new_labels" flag for class_labels tensor

deeplake/api/tests/test_api.py

@@ -1988,6 +1988,31 @@ def test_partial_read_then_write(s3_ds_generator):
         ds.xyz[1] = 20 * np.ones((1000, 1000))
 
 
+def test_allow_new_labels(local_ds):
+    with local_ds as ds:
+        ds.create_tensor("dynamic_labels", htype="class_label")
+        ds.create_tensor(
+            "fixed_labels",
+            htype="class_label",
+            class_names=["a", "b", "c"],
+            allow_new_labels=False,
+        )
+
+        ds.dynamic_labels.append("a")
+        ds.dynamic_labels.append("a")
+        ds.fixed_labels.append("a")
+        ds.fixed_labels.append("b")
+        assert ds.dynamic_labels.info["class_names"] == ["a"]
+        assert ds.fixed_labels.info["class_names"] == ["a", "b", "c"]
+
+        with pytest.raises(SampleAppendError):
+            ds.fixed_labels.append("new_one")
+
+        ds.fixed_labels.info.update(allow_new_labels=False)
+        with pytest.raises(SampleAppendError):
+            ds.fixed_labels.append("new_one")
+
+
 def test_exist_ok(local_ds):
     with local_ds as ds:
         ds.create_tensor("abc")

deeplake/core/chunk_engine.py

@@ -789,6 +789,13 @@ def _convert_class_labels(self, samples):
         class_names = tensor_info.class_names
         labels, additions = convert_to_idx(samples, class_names)
         if additions:
+            if (
+                "allow_new_labels" in tensor_info
+                and tensor_info["allow_new_labels"] is False
+            ):
+                raise ValueError(
+                    f"New label(s) [{','.join([i[0] for i in additions])}] are not allowed for tensor {tensor_name}. Allowed labels are: [{','.join(tensor_info.class_names)}]"
+                )
             for new in additions:
                 class_names.append(new[0])
                 logger.info(

deeplake/htype.py

@@ -64,7 +64,11 @@ class htype:
     htype.CLASS_LABEL: {
         "dtype": "uint32",
         "class_names": [],
-        "_info": ["class_names"],  # class_names should be stored in info, not meta
+        "allow_new_labels": True,
+        "_info": [
+            "class_names",
+            "allow_new_labels",
+        ],  # class_names should be stored in info, not meta
         "_disable_temp_transform": False,
     },
     htype.BBOX: {"dtype": "float32", "coords": {}, "_info": ["coords"]},