hmr 2.1.0

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

Changelog

2.1.0

Focus on perceived reload latency and terminal UX polish. No breaking changes — existing 2.0.0 setups upgrade in place.

New

• Smart default exclusions: when no hmr.excludes is set in pubspec.yaml, irrelevant noise (test/, build/, doc(s)/, .git/, .idea/, .vscode/, editor swap files, .DS_Store, …) is skipped to cut perceived reload time. Setting hmr.excludes opts out of the defaults and gives you full control. .dart_tool/ is always ignored regardless.
• Immediate compile feedback: the reload line is rendered the moment a file change is observed (CompileStarted) instead of waiting for the VM to finish. The full restart vs. hot reload verb is decided upfront and shown as the definitive label, so there's no dim-then-swap flicker.
• "hot restart" label is now shown when the entrypoint file itself is modified (previously displayed as "update"), matching the underlying behavior of forcing a full process restart.
• lib/src/version.dart exposes the package version for CLI surfacing.

Changed

• JSON event payloads use shorter, less ambiguous kind values: hotReload → reload, hotRestart → restart. The internal ReloadKind enum is unchanged. Consumers of --format=json need to update any field they assert on.
• Removed the "compiled in xx ms" suffix from terminal output — the verb + trigger line is enough; the timing wasn't actionable.

Fixes

• Force a full restart when the entrypoint file is modified. A hot reload would re-load the source but never re-execute main(), leaving the app in a stale state.
• Detect post-restart crashes and emit CompileFailed so the error is rendered in place of a stale "reloading…" header.
• Suppress the reloading header when a reload resolves to an error — only the error itself is shown.
• Suppress remaining VM-service info lines that occasionally leaked into child stdout/stderr.
• Restart the child process when the VM service connection is disposed with an RPC error, instead of hanging on a dead socket.
• Close the RuntimeBridge startup race more reliably by polling for the ext.hmr.dispatch extension during initial child startup.

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