flutter_hook_config

A package:hooks protocol extension that lets the Flutter SDK pass Flutter-specific configuration to build and link hooks in a typed way.

Today it exposes the absolute paths of the engine host tools a hook might need:

• impellerc, the offline shader compiler (used, for example, by flutter_gpu_shaders to compile .shaderbundle.json files).
• libtessellator, the tessellation library.

The Flutter SDK (flutter_tools) resolves these through the same artifact lookup it uses for its own build steps, so under --local-engine a hook gets the locally built tools, matching the engine the app is being built against, instead of the ones in the SDK cache.

For hook authors

Add flutter_hook_config to your hook's dependencies and read the config from the BuildInput / LinkInput via input.config.flutter. Always check input.config.buildForFlutter first: a hook may also be invoked by a plain dart build, or by a Flutter SDK that predates this extension, in which case no Flutter-specific config is available and you should fall back to your own tool discovery.

See the library documentation for a usage example.

For the Flutter SDK

flutter_tools constructs a FlutterExtension (populated from Artifacts.getHostArtifact(...)) and passes it to the hook runner alongside the other protocol extensions (CodeAssetExtension, DataAssetsExtension), so the configuration above becomes available to every build and link hook.