Abort sass if stdin is closed when watching

bin/sass.dart

@@ -54,6 +54,7 @@ Future<void> main(List<String> args) async {
     var graph = StylesheetGraph(
         ImportCache(loadPaths: options.loadPaths, logger: options.logger));
     if (options.watch) {
+      ensureWatchWillExit();
       await watch(options, graph);
       return;
     }

lib/src/io/interface.dart

@@ -94,6 +94,14 @@ String? getEnvironmentVariable(String name) => throw '';
 int get exitCode => throw '';
 set exitCode(int value) => throw '';
 
+/// Attaches a listener to exit when stdin closes.
+///
+/// The listener is *not* attached when stdin is a TTY because it would
+/// interfere with the Unix background job system. If we read from stdin and
+/// then Ctrl+Z to move the process to the background, it will incorrectly
+/// cause the job to stop. See: https://github.com/brunch/brunch/issues/998.
+void ensureWatchWillExit() => throw '';
+
 /// Recursively watches the directory at [path] for modifications.
 ///
 /// Returns a future that completes with a single-subscription stream once the

lib/src/io/node.dart

@@ -196,6 +196,9 @@ final stderr = Stderr(process.stderr);
 @JS('process.stdout.isTTY')
 external bool? get isTTY;
 
+@JS('process.stdin.isTTY')
+external bool? get isStdinTTY;
+
 bool get hasTerminal => isTTY == true;
 
 bool get isWindows => process.platform == 'win32';
@@ -213,6 +216,12 @@ int get exitCode => process.exitCode;
 
 set exitCode(int code) => process.exitCode = code;
 
+void ensureWatchWillExit() {
+  if (isStdinTTY == true) {
+    process.stdin.on('end', allowInterop(() => process.exit(0)));
+  }
+}
+
 Future<Stream<WatchEvent>> watchDir(String path, {bool poll = false}) {
   var watcher = chokidar.watch(
       path, ChokidarOptions(disableGlobbing: true, usePolling: poll));

lib/src/io/vm.dart

@@ -87,6 +87,10 @@ DateTime modificationTime(String path) {
 
 String? getEnvironmentVariable(String name) => io.Platform.environment[name];
 
+void ensureWatchWillExit() {
+  if (!io.stdin.hasTerminal) io.stdin.listen(null, onDone: () => io.exit(0));
+}
+
 Future<Stream<WatchEvent>> watchDir(String path, {bool poll = false}) async {
   var watcher = poll ? PollingDirectoryWatcher(path) : DirectoryWatcher(path);