build_runner_accelerator

A Rust-accelerated frontend for build_runner. Rust plans actions and manages incremental state; a Dart worker runs builders through build_runner APIs.

Requires Dart >=3.11.0 <4.0.0 and build_runner >=2.15.3 <2.18.0. See supported dependencies for compatibility details. Support applies to the validated configurations in the compatibility inventory, not every feature of a named builder. Read the compatibility contract before adopting it.

Performance

In user-reported measurements of a real-world Flutter application, cache-warm clean builds were 2.6× faster than stock build_runner (repeat count and variability not reported). Across two environments, clean builds including AOT compilation with analyzer caches cleared were approximately 1.1× faster, and no-op builds were 2.2–4.1× faster.

Our 500-feature mixed-builder benchmark measured 1.2× faster clean builds and 4.6× faster warm no-op builds. These are Linux measurements; see benchmarks for cache definitions, conditions and results.

Installation

The current package version is 0.16.1.

Add the package to your application:

dart pub add dev:build_runner_accelerator:^0.16.1

Or add it to pubspec.yaml:

dev_dependencies:
  build_runner_accelerator: ^0.16.1

Then use the project-local command:

dart run build_runner_accelerator build
dart run build_runner_accelerator watch

To warm the worker before the first build, run this after pub get:

dart run build_runner_accelerator prewarm --background

Prewarm prepares caches but does not run build actions. It is optional.

Before you build

The launcher downloads and verifies a matching native binary. Published targets are Linux x64/arm64, macOS arm64, and Windows x64/arm64; platform limits are in binary selection. Unsupported requests or an unavailable binary fail explicitly. The accelerator never starts stock build_runner; run dart run build_runner build directly when needed. Stop native commands before running stock in the same workspace, and follow the recovery guide before returning to native.

Builder failures leave outputs and the graph at their last successful state. Interrupted publication is recovered before the next build/watch; preserve any pending undo evidence. Publication is not a simultaneous atomic snapshot and has no power-loss durability guarantee. See interrupted publication.

Common options

# Build selected outputs and their dependencies.
dart run build_runner_accelerator build --build-filter='lib/*.g.dart'

# Verify generated outputs without changing them (exit 1 on differences).
dart run build_runner_accelerator build --only-check

# Retain manual output edits until their producer reruns.
dart run build_runner_accelerator build --keep-modified-outputs

Output policies are build-only and mutually exclusive. Filters and policies have compatibility limits; see the CLI reference. For build.yaml, named configs and --define, see configuration. Upgrading from an older version? See the migration guide.

Documentation and contributing

The documentation index separates usage, contribution guides, and historical evidence. Start with development to contribute, benchmarks for measured performance, or the roadmap for remaining release gates.