Validate extension name before toggling through CLI (#1509)

Co-authored-by: Zach Sailer <zsailer@apple.com>

Author: Darshan808

jupyter_server/extension/serverextension.py

@@ -259,9 +259,23 @@ def toggle_server_extension(self, import_name: str) -> None:
             self.log.info(f"- Writing config: {config_dir}")
             # Validate the server extension.
             self.log.info(f"    - Validating {import_name}...")
+            config = extension_manager.config_manager
+            enabled = False
+            if config:
+                jpserver_extensions = config.get_jpserver_extensions()
+                if import_name not in jpserver_extensions:
+                    msg = (
+                        f"The module '{import_name}' could not be found. Are you "
+                        "sure the extension is installed?"
+                    )
+                    raise ValueError(msg)
+                enabled = jpserver_extensions[import_name]
+
             # Interface with the Extension Package and validate.
-            extpkg = ExtensionPackage(name=import_name)
-            extpkg.validate()
+            extpkg = ExtensionPackage(name=import_name, enabled=enabled)
+            if not extpkg.validate():
+                msg = "validation failed"
+                raise ValueError(msg)
             version = extpkg.version
             self.log.info(f"      {import_name} {version} {GREEN_OK}")
 

tests/extension/test_serverextension.py

@@ -134,3 +134,11 @@ def test_server_extension_apps(jp_env_config_path, jp_extension_environ):
 def test_server_extension_app():
     app = ServerExtensionApp()
     app.launch_instance(["list"])
+
+
+def test_toggle_missing_server_extension(jp_env_config_path, capsys):
+    app = ToggleServerExtensionApp()
+    app.extra_args = ["missingextension"]
+    app.start()
+    captured = capsys.readouterr()
+    assert "Validation failed: The module 'missingextension' could not be found." in captured.err