Handle client 8 support

nbclient/client.py

@@ -491,12 +491,6 @@ def create_kernel_manager(self) -> KernelManager:
         else:
             self.km = self.kernel_manager_class(kernel_name=self.kernel_name, config=self.config)
         assert self.km is not None
-
-        # If the current kernel manager is still using the default (synchronous) KernelClient class,
-        # switch to the async version since that's what NBClient prefers.
-        if self.km.client_class == 'jupyter_client.client.KernelClient':
-            self.km.client_class = 'jupyter_client.asynchronous.AsyncKernelClient'
-
         return self.km
 
     async def _async_cleanup_kernel(self) -> None:

nbclient/tests/test_client.py

@@ -635,6 +635,17 @@ def timeout_func(source):
         with pytest.raises(TimeoutError):
             run_notebook(filename, dict(timeout_func=timeout_func), res)
 
+    def test_sync_kernel_manager(self):
+        nb = nbformat.v4.new_notebook()  # Certainly has no language_info.
+        executor = NotebookClient(nb, kernel_name="python", kernel_manager_class=KernelManager)
+        nb = executor.execute()
+        assert 'language_info' in nb.metadata
+        with executor.setup_kernel():
+            assert executor.kc is not None
+            info_msg = executor.wait_for_reply(executor.kc.kernel_info())
+            assert info_msg is not None
+            assert 'name' in info_msg["content"]["language_info"]
+
     def test_kernel_death_after_timeout(self):
         """Check that an error is raised when the kernel is_alive is false after a cell timed out"""
         filename = os.path.join(current_dir, 'files', 'Interrupt.ipynb')
@@ -653,9 +664,10 @@ async def is_alive():
             return False
 
         km.is_alive = is_alive
-        # Will be a RuntimeError or subclass DeadKernelError depending
+        # Will be a RuntimeError, TimeoutError, or subclass DeadKernelError
+        # depending
         # on if jupyter_client or nbconvert catches the dead client first
-        with pytest.raises(RuntimeError):
+        with pytest.raises((RuntimeError, TimeoutError)):
             input_nb, output_nb = executor.execute()
 
     def test_kernel_death_during_execution(self):