Debugging DevTools Extensions

Follow this workflow to test and debug DevTools extensions locally.

1. Local Stub Extensions Mode (No Server Needed)

When running DevTools in standalone web mode (flutter run -d chrome), DevTools does not run the devtools_server backend by default. To test extensions without a running server backend:

1. Open packages/devtools_app/lib/src/shared/development_helpers.dart.
2. Set const _debugDevToolsExtensions = true;.

[!WARNING] Never commit _debugDevToolsExtensions = true; to git. A repository unit test (development_helpers_test.dart) enforces that this flag remains false.

Activating stub mode registers the following mock extensions:

• foo_ext (package:foo)
• bar_ext (package:bar)
• provider_ext (package:provider)