Check for serverapp for reraise flag (#887)

* Check for serverapp for reraise flag

The supporting serverextension apps (enable/disable/list) should probably always complete even if an exception raises an error, so in those cases, default to just warning about exceptions, but still complete.

* Add regtest for ExtensionManager wo/serverapp

It should not raise exceptions if there is no serverapp.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fix lint

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Steven Silvester <[email protected]>

Author: 3 people

jupyter_server/extension/manager.py

@@ -322,7 +322,7 @@ def add_extension(self, extension_name, enabled=False):
             return True
         # Raise a warning if the extension cannot be loaded.
         except Exception as e:
-            if self.serverapp.reraise_server_extension_failures:
+            if self.serverapp and self.serverapp.reraise_server_extension_failures:
                 raise
             self.log.warning(
                 "%s | error adding extension (enabled: %s): %s",
@@ -343,7 +343,7 @@ def link_extension(self, name):
                 self.linked_extensions[name] = True
                 self.log.info("%s | extension was successfully linked.", name)
             except Exception as e:
-                if self.serverapp.reraise_server_extension_failures:
+                if self.serverapp and self.serverapp.reraise_server_extension_failures:
                     raise
                 self.log.warning("%s | error linking extension: %s", name, e, exc_info=True)
 
@@ -354,7 +354,7 @@ def load_extension(self, name):
             try:
                 extension.load_all_points(self.serverapp)
             except Exception as e:
-                if self.serverapp.reraise_server_extension_failures:
+                if self.serverapp and self.serverapp.reraise_server_extension_failures:
                     raise
                 self.log.warning("%s | extension failed loading with message: %s", name, e)
                 self.log.exception("%s | stack trace", name)

tests/extension/test_manager.py

@@ -1,5 +1,6 @@
 import os
 import unittest.mock as mock
+from contextlib import nullcontext
 
 import pytest
 from jupyter_core.paths import jupyter_config_path
@@ -96,39 +97,42 @@ def test_extension_manager_linked_extensions(jp_serverapp):
     assert name in manager.linked_extensions
 
 
-def test_extension_manager_fail_add(jp_serverapp):
+@pytest.mark.parametrize("has_app", [True, False])
+def test_extension_manager_fail_add(jp_serverapp, has_app):
     name = "tests.extension.notanextension"
-    manager = ExtensionManager(serverapp=jp_serverapp)
+    manager = ExtensionManager(serverapp=jp_serverapp if has_app else None)
     manager.add_extension(name, enabled=True)  # should only warn
     jp_serverapp.reraise_server_extension_failures = True
-    with pytest.raises(ExtensionModuleNotFound):
-        manager.add_extension(name, enabled=True)
+    with pytest.raises(ExtensionModuleNotFound) if has_app else nullcontext():
+        assert manager.add_extension(name, enabled=True) is False
 
 
-def test_extension_manager_fail_link(jp_serverapp):
+@pytest.mark.parametrize("has_app", [True, False])
+def test_extension_manager_fail_link(jp_serverapp, has_app):
     name = "tests.extension.mockextensions.app"
     with mock.patch(
         "tests.extension.mockextensions.app.MockExtensionApp.parse_command_line",
         side_effect=RuntimeError,
     ):
-        manager = ExtensionManager(serverapp=jp_serverapp)
+        manager = ExtensionManager(serverapp=jp_serverapp if has_app else None)
         manager.add_extension(name, enabled=True)
         manager.link_extension(name)  # should only warn
         jp_serverapp.reraise_server_extension_failures = True
-        with pytest.raises(RuntimeError):
+        with pytest.raises(RuntimeError) if has_app else nullcontext():
             manager.link_extension(name)
 
 
-def test_extension_manager_fail_load(jp_serverapp):
+@pytest.mark.parametrize("has_app", [True, False])
+def test_extension_manager_fail_load(jp_serverapp, has_app):
     name = "tests.extension.mockextensions.app"
     with mock.patch(
         "tests.extension.mockextensions.app.MockExtensionApp.initialize_handlers",
         side_effect=RuntimeError,
     ):
-        manager = ExtensionManager(serverapp=jp_serverapp)
+        manager = ExtensionManager(serverapp=jp_serverapp if has_app else None)
         manager.add_extension(name, enabled=True)
         manager.link_extension(name)
         manager.load_extension(name)  # should only warn
         jp_serverapp.reraise_server_extension_failures = True
-        with pytest.raises(RuntimeError):
+        with pytest.raises(RuntimeError) if has_app else nullcontext():
             manager.load_extension(name)