hmr 2.0.0

Hot Module Replacement system specially designed for command-line Dart applications.

Changelog

2.0.0

Flutter-grade HMR for CLI Dart applications. Major rewrite around the Dart VM service: true hot reload (no recompilation pipeline, no isolate restart), preserved app state, and a child-side runtime API for reacting to events.

Highlights

Three supported usage modes:

1. Built-in CLI (hmr) — zero-config supervisor for the 80% case.
2. Runtime API (package:hmr/runtime.dart) — opt into typed hooks (onReload, onRestart, onFile*) from inside your app.
3. Custom runner (package:hmr/hmr.dart) — compose VmServiceProcessStrategy, FileWatcher, filters, presenters and HotKeyController to build your own supervisor. See example/bin/custom_hmr.dart.

New

• VmServiceProcessStrategy — launches the entrypoint as a child process with --enable-vm-service=0, then issues reloadSources on file changes.
• Automatic fallback from hot reload to a full restart on shape changes.
• Full restart automatically triggered when the entrypoint file itself is modified (a hot reload would skip main() re-execution).
• package:hmr/runtime.dart — opt-in Hmr.instance API for the child process to subscribe to typed events (onReload, onRestart, onFileCreated, onFileModified, onFileDeleted, onFileMoved, or a generic on<E>). Handler exceptions are caught and logged — a buggy hook can never crash the supervised app. No-op outside the supervisor, so the same main() works for both hmr and plain dart run.
• RuntimeBridge forwards events from the parent to the child via the ext.hmr.dispatch VM service extension, with bounded polling to absorb child startup latency without dropping early events.
• Hot keys: r (reload), R (restart), c (clear), h (help), q (quit).
• Structured event model with JSON serialization (--format=json) covering started, compileStarted, compileSucceeded, compileFailed, reloadSucceeded, reloadFailed, fileChanged, processCrashed, stopped. Same shape consumed by the runtime API.
• ProcessCrashed preserves the full child stderr verbatim — no truncation.
• EntrypointResolver with a documented priority chain: CLI arg → pubspec hmr.entrypoint → bin/<package>.dart → bin/main.dart.
• example/bin/custom_hmr.dart — runnable template for building your own supervisor from the library's building blocks.

Breaking

• Removed IsolateRestartStrategy and the --strategy flag — every run uses the VM-service strategy.
• Removed the --rescan-extension flag (use the runtime API instead).
• Renamed impl/ to example/ (pub.dev convention).
• Renamed VmServiceReloadStrategy → VmServiceProcessStrategy.
• Removed the legacy Runner / Watcher / IgnoreMiddleware / DebounceMiddleware / IncludeMiddleware API; build a custom supervisor with ReloadOrchestrator + FileWatcher + ignoreSegment/includeGlobs/ excludeGlobs filters instead.

Fixes

• Surface a clear, red error message when the configured entrypoint does not exist, instead of the cryptic Bad state: VM service URI not found in child process output.
• Stop dropping early runtime-API events: RuntimeBridge.init now polls the isolate (default 500 ms) for ext.hmr.dispatch instead of checking once, closing the race between parent VM-service handshake and child main().
• Suppress VM-service URI lines from child stdout/stderr so terminal output stays focused on app logs.
• Detect post-restart crashes and emit CompileFailed so reload errors are rendered without a stale "reloading…" header.

Docs

• Rewritten README.md with a table of contents, the three usage modes, a full pubspec.yaml schema reference, CLI flags, runtime API table, and a table of every library symbol exported for custom runners.
• New example/README.md covering both the watched-app demo and the custom_hmr.dart template.

1.4.1

• remove SIGTERM on windows

1.4.0

• Expose send and listen methods
• Request SendPort from Isolate to send messages in the Isolate

1.3.2

• Change debounce middleware order

1.3.1

• Remove debounce delay by default

1.3.0

• Migrate filters to responsibility chain pattern

1.2.0

• Implement debounce delay
• Ignore .dart_tool and IDE directories by default

1.1.2

• Remove ProcessSignal.SIGTERM

1.1.1

• Fix entrypoint implicite extension

1.1.0

• Transfert hmr [...args] to Isolate

1.0.3

• Add newline on exit to prevent terminal prompt bad display

1.0.2

• Enforce clear screen on start
• Enforce clear screen on reload

1.0.1

• Prevent the hmr command from being run in a non-Dart project
• Add clean-up of temporary files on exit

1.0.0

Initial Release - Première publication officielle du package HMR pour Dart

• Hot reload without restarting the application

• State retention between reloads

• Automated kernel compilation via dart compile.

• Glob patterns for inclusion/exclusion (**/*.dart)

• Detection of modifications/creations/deletions/moves

• Configurable debounce mechanism

• Visual feedback with ANSI codes (colours, positioning)

• Own compile error handling

• Successive changes counter