[AL-1710] Allow branch creation when dataset is locked (#1584)

hub/api/tests/test_api.py

@@ -22,6 +22,7 @@
     InvalidTensorNameError,
     PathNotEmptyException,
     BadRequestException,
+    ReadOnlyModeError,
 )
 from hub.util.pretty_print import summary_tensor, summary_dataset
 from hub.constants import MB
@@ -1427,3 +1428,13 @@ def test_pyav_not_installed(local_ds, video_paths):
     with pytest.raises(hub.util.exceptions.CorruptedSampleError):
         local_ds.videos.append(hub.read(video_paths["mp4"][0]))
     hub.core.compression._PYAV_INSTALLED = pyav_installed
+
+
+def test_create_branch_when_locked_out(local_ds):
+    local_ds.read_only = True
+    local_ds._locked_out = True
+    with pytest.raises(ReadOnlyModeError):
+        local_ds.create_tensor("x")
+    local_ds.checkout("branch", create=True)
+    assert local_ds.branch == "branch"
+    local_ds.create_tensor("x")

hub/core/dataset/dataset.py

@@ -848,16 +848,28 @@ def _checkout(
             raise Exception(
                 "Cannot perform version control operations on a filtered dataset view."
             )
-
+        if self._locked_out:
+            self.storage.disable_readonly()
+            self._read_only = False
+            base_storage = get_base_storage(self.storage)
+            base_storage.disable_readonly()
         try_flushing(self)
-
         self._initial_autoflush.append(self.storage.autoflush)
         self.storage.autoflush = False
+        err = False
         try:
             self._unlock()
             checkout(self, address, create, hash)
-            self._lock()
+        except Exception as e:
+            err = True
+            if self._locked_out:
+                self.storage.enable_readonly()
+                self._read_only = True
+                base_storage.enable_readonly()
+            raise e
         finally:
+            if not (err and self._locked_out):
+                self._lock()
             self.storage.autoflush = self._initial_autoflush.pop()
         self._info = None
         self._ds_diff = None