Enable notebook ContentsManager in jupyter_server

.github/workflows/python-windows.yml

@@ -44,7 +44,12 @@ jobs:
         pip check
     - name: Run the tests
       run: |
-        pytest -vv
+        # Disable capturing (-s) output from Pytest on Windows.
+        # For an unknown reason, capturing output interferes with
+        # the file descriptions opened by the asyncio IOLoop.
+        # This leads to a nasty, flaky race condition that we haven't
+        # been able to solve.
+        pytest -vv -s
     - name: Install the Python dependencies for the examples
       run: |
         cd examples/simple && pip install -e .

jupyter_server/serverapp.py

@@ -31,6 +31,7 @@
 import warnings
 import webbrowser
 import urllib
+import inspect
 
 from base64 import encodebytes
 try:
@@ -106,6 +107,7 @@
 from jupyter_server.extension.serverextension import ServerExtensionApp
 from jupyter_server.extension.manager import ExtensionManager
 from jupyter_server.extension.config import ExtensionConfigManager
+from jupyter_server.traittypes import TypeFromClasses
 
 #-----------------------------------------------------------------------------
 # Module globals
@@ -1134,13 +1136,43 @@ def template_file_path(self):
         help="""If True, display controls to shut down the Jupyter server, such as menu items or buttons."""
     )
 
-    contents_manager_class = Type(
+    # REMOVE in VERSION 2.0
+    # Temporarily allow content managers to inherit from the 'notebook'
+    # package. We will deprecate this in the next major release.
+    contents_manager_class = TypeFromClasses(
         default_value=LargeFileManager,
-        klass=ContentsManager,
+        klasses=[
+            'jupyter_server.services.contents.manager.ContentsManager',
+            'notebook.services.contents.manager.ContentsManager'
+        ],
         config=True,
         help=_('The content manager class to use.')
     )
 
+    # Throws a deprecation warning to notebook based contents managers.
+    @observe('contents_manager_class')
+    def _observe_contents_manager_class(self, change):
+        new = change['new']
+        # If 'new' is a class, get a string representing the import
+        # module path.
+        if inspect.isclass(new):
+            new = new.__module__
+
+        if new.startswith('notebook'):
+            self.log.warning(
+                "The specified 'contents_manager_class' class inherits a manager from the "
+                "'notebook' package. This is not guaranteed to work in future "
+                "releases of Jupyter Server. Instead, consider switching the "
+                "manager to inherit from the 'jupyter_server' managers. "
+                "Jupyter Server will temporarily allow 'notebook' managers "
+                "until its next major release (2.x)."
+            )
+
+    @observe('notebook_dir')
+    def _update_notebook_dir(self, change):
+        self.log.warning(_("notebook_dir is deprecated, use root_dir"))
+        self.root_dir = change['new']
+
     kernel_manager_class = Type(
         default_value=MappingKernelManager,
         config=True,

jupyter_server/services/sessions/sessionmanager.py

@@ -18,12 +18,18 @@
 from traitlets import Instance
 
 from jupyter_server.utils import ensure_async
+from jupyter_server.traittypes import InstanceFromClasses
 
 
 class SessionManager(LoggingConfigurable):
 
     kernel_manager = Instance('jupyter_server.services.kernels.kernelmanager.MappingKernelManager')
-    contents_manager = Instance('jupyter_server.services.contents.manager.ContentsManager')
+    contents_manager = InstanceFromClasses(
+        [
+            'jupyter_server.services.contents.manager.ContentsManager',
+            'notebook.services.contents.manager.ContentsManager'
+        ]
+    )
 
     # Session database initialized below
     _cursor = None