Fix get_kernel_path for AsyncFileManagers. (#929)

Author: thetorpedodog

jupyter_server/services/contents/filemanager.py

@@ -904,3 +904,13 @@ async def is_hidden(self, path):
         path = path.strip("/")
         os_path = self._get_os_path(path=path)
         return is_hidden(os_path, self.root_dir)
+
+    async def get_kernel_path(self, path, model=None):
+        """Return the initial API path of a kernel associated with a given notebook"""
+        if await self.dir_exists(path):
+            return path
+        if "/" in path:
+            parent_dir = path.rsplit("/", 1)[0]
+        else:
+            parent_dir = ""
+        return parent_dir

jupyter_server/services/sessions/sessionmanager.py

@@ -271,7 +271,7 @@ async def create_session(
     async def start_kernel_for_session(self, session_id, path, name, type, kernel_name):
         """Start a new kernel for a given session."""
         # allow contents manager to specify kernels cwd
-        kernel_path = self.contents_manager.get_kernel_path(path=path)
+        kernel_path = await ensure_async(self.contents_manager.get_kernel_path(path=path))
         kernel_id = await self.kernel_manager.start_kernel(
             path=kernel_path,
             kernel_name=kernel_name,