# Development

[README](../README.md)

Local verification and implementation constraints. See [architecture](architecture.md) for ownership and frontend contracts.

## Verify

```sh
cargo test
cargo clippy --all-targets -- -D warnings
cargo fmt --check
ruby -c src/ruby_host.rb
```

## Test organization

Rust tests live alongside their modules; native LSP integration checks are in [`tests/lsp.rs`](../tests/lsp.rs).

- Editor checks cover Unicode editing, multi-target state, undo/redo, saving failures, and modal paste acceptance and rejection atomicity.
- Session and Ruby checks exercise real Ruby execution, command/capability ownership, effect validation, configuration fallback, plugin retirement, crash/timeout recovery, and inherited-pipe cleanup.
- Unix terminal-hook checks use isolated child processes and real PTYs to keep process-global hooks out of the parallel runner. They cover cleanup on entry failure, normal return, I/O errors, and panics, including original panic-payload propagation.
- Native LSP integration checks launch framed-protocol fixture subprocesses, covering initialization/settings, opt-in startup, synchronization, UTF-16/file-URI conversion, dirty targets, stale requests/diagnostics, and transport failures.
- Hover regression checks cover content forms, sanitization, cancelled/superseded replies, invalid results, scrolling/dismissal, Unicode clipping, and preserved editing state.

Clipboard checks use isolated providers rather than reading or overwriting the desktop clipboard.

## Performance and process limits

- Undo uses full-buffer snapshots and movement scans the current line. This favors straightforward correctness over large-file performance.
- Legacy synchronous plugin invocation may pause input for up to 500 ms before a host timeout. Async plugins opt into background replies; pending requests and transport queues are bounded. Config/plugin startup has a 2-second deadline per host. Buffer context/document snapshots must fit within a 4 MiB JSON frame; a too-large frame disables that plugin, not editing.

See [syntax caches](architecture.md#syntax-caches) for the current full-tree highlighting ceiling.