README.md

Rewatch build system

Rewatch is the Rust implementation of the ReScript build and watch commands. It reads rescript.json, discovers packages and source files, maintains module dependencies, and invokes the compiler in dependency order.

Code map

• src/config.rs parses configuration and converts supported settings to compiler arguments.
• src/build/packages.rs discovers packages and resolves package dependencies.
• src/build/parse.rs produces compiler AST artifacts.
• src/build/deps.rs builds the module dependency graph.
• src/build/compile.rs invokes the compiler and updates build artifacts.
• src/watcher.rs maps filesystem and configuration changes to incremental rebuilds.
• src/cli.rs and src/main.rs own command-line parsing and dispatch.

Focused documentation:

• configuration support matrix
• monorepo discovery and build scope
• feature-gated source directories
• integration-test workspace

The ReScript website owns user-facing configuration documentation. The support matrix in this directory records what the current Rewatch implementation accepts, including compatibility fields which are not recommended for new projects.

Building and testing

Run commands from the repository root:

make rewatch
make test-rewatch
cargo test --manifest-path rewatch/Cargo.toml
cargo clippy --manifest-path rewatch/Cargo.toml --all-targets --all-features
cargo fmt --check --manifest-path rewatch/Cargo.toml

The integration suite is tests/suite.sh. It creates and modifies projects under testrepo/; use its helpers for portable path and file operations rather than adding platform-specific sed commands or fixed sleeps.

When a CLI or configuration value affects compilation, trace it through both build and watch entry points. Command-line values override project configuration. Keep that precedence and the compiler-argument conversion in one owning layer where possible, and add both unit and integration coverage.

Put public Rust API contracts in source documentation, local algorithm or state invariants beside their implementation, and cross-module navigation in this guide. Update or remove focused documents when the implementation changes; do not preserve completed plans as descriptions of current behavior.