Add a --stop-on-error flag (#391)

Closes #264

CHANGELOG.md

@@ -5,6 +5,9 @@
 * Add a `--poll` flag to make `--watch` mode repeatedly check the filesystem for
   updates rather than relying on native filesystem notifications.
 
+* Add a `--stop-on-error` flag to stop compiling additional files once an error
+  is encountered.
+
 ## 1.7.3
 
 * No user-visible changes.

lib/src/executable.dart

@@ -80,12 +80,14 @@ main(List<String> args) async {
         //
         // We let exitCode 66 take precedence for deterministic behavior.
         if (exitCode != 66) exitCode = 65;
+        if (options.stopOnError) return;
       } on FileSystemException catch (error, stackTrace) {
         printError("Error reading ${p.relative(error.path)}: ${error.message}.",
             options.trace ? stackTrace : null);
 
         // Error 66 indicates no input.
         exitCode = 66;
+        if (options.stopOnError) return;
       }
     }
   } on UsageException catch (error) {

lib/src/executable/options.dart

@@ -79,6 +79,8 @@ class ExecutableOptions {
           help: 'Manually check for changes rather than using a native '
               'watcher.\n'
               'Only valid with --watch.')
+      ..addFlag('stop-on-error',
+          help: "Don't compile more files once an error is encountered.")
       ..addFlag('interactive',
           abbr: 'i',
           help: 'Run an interactive SassScript shell.',
@@ -177,6 +179,10 @@ class ExecutableOptions {
   /// Whether to manually poll for changes when watching.
   bool get poll => _options['poll'] as bool;
 
+  /// Whether to stop compiling additional files once one file produces an
+  /// error.
+  bool get stopOnError => _options['stop-on-error'] as bool;
+
   /// A map from source paths to the destination paths where the compiled CSS
   /// should be written.
   ///

lib/src/executable/watch.dart

@@ -41,7 +41,11 @@ Future watch(ExecutableOptions options, StylesheetGraph graph) async {
     var destination = options.sourcesToDestinations[source];
     graph.addCanonical(new FilesystemImporter('.'),
         p.toUri(p.canonicalize(source)), p.toUri(source));
-    await watcher.compile(source, destination, ifModified: true);
+    var success = await watcher.compile(source, destination, ifModified: true);
+    if (!success && options.stopOnError) {
+      dirWatcher.events.listen(null).cancel();
+      return;
+    }
   }
 
   print("Sass is watching for changes. Press Ctrl-C to stop.\n");
@@ -51,25 +55,34 @@ Future watch(ExecutableOptions options, StylesheetGraph graph) async {
 /// Holds state that's shared across functions that react to changes on the
 /// filesystem.
 class _Watcher {
+  /// The options for the Sass executable.
   final ExecutableOptions _options;
 
+  /// The graph of stylesheets being compiled.
   final StylesheetGraph _graph;
 
   _Watcher(this._options, this._graph);
 
   /// Compiles the stylesheet at [source] to [destination], and prints any
   /// errors that occur.
-  Future compile(String source, String destination,
+  ///
+  /// Returns whether or not compilation succeeded.
+  Future<bool> compile(String source, String destination,
       {bool ifModified: false}) async {
     try {
       await compileStylesheet(_options, _graph, source, destination,
           ifModified: ifModified);
+      return true;
     } on SassException catch (error, stackTrace) {
       _delete(destination);
       _printError(error.toString(color: _options.color), stackTrace);
+      exitCode = 65;
+      return false;
     } on FileSystemException catch (error, stackTrace) {
       _printError("Error reading ${p.relative(error.path)}: ${error.message}.",
           stackTrace);
+      exitCode = 66;
+      return false;
     }
   }
 
@@ -97,7 +110,7 @@ class _Watcher {
       stderr.writeln(new Trace.from(stackTrace).terse.toString().trimRight());
     }
 
-    stderr.writeln();
+    if (!_options.stopOnError) stderr.writeln();
   }
 
   /// Listens to `watcher.events` and updates the filesystem accordingly.
@@ -119,11 +132,13 @@ class _Watcher {
           // from the graph.
           var node = _graph.nodes[url];
           _graph.reload(url);
-          await _recompileDownstream([node]);
+          var success = await _recompileDownstream([node]);
+          if (!success && _options.stopOnError) return;
           break;
 
         case ChangeType.ADD:
-          await _retryPotentialImports(event.path);
+          var success = await _retryPotentialImports(event.path);
+          if (!success && _options.stopOnError) return;
 
           var destination = _destinationFor(event.path);
           if (destination == null) continue loop;
@@ -131,11 +146,13 @@ class _Watcher {
           _graph.addCanonical(
               new FilesystemImporter('.'), url, p.toUri(event.path));
 
-          await compile(event.path, destination);
+          success = await compile(event.path, destination);
+          if (!success && _options.stopOnError) return;
           break;
 
         case ChangeType.REMOVE:
-          await _retryPotentialImports(event.path);
+          var success = await _retryPotentialImports(event.path);
+          if (!success && _options.stopOnError) return;
           if (!_graph.nodes.containsKey(url)) continue loop;
 
           var destination = _destinationFor(event.path);
@@ -143,7 +160,8 @@ class _Watcher {
 
           var downstream = _graph.nodes[url].downstream;
           _graph.remove(url);
-          await _recompileDownstream(downstream);
+          success = await _recompileDownstream(downstream);
+          if (!success && _options.stopOnError) return;
           break;
       }
     }
@@ -176,29 +194,38 @@ class _Watcher {
 
   /// Recompiles [nodes] and everything that transitively imports them, if
   /// necessary.
-  Future _recompileDownstream(Iterable<StylesheetNode> nodes) async {
+  ///
+  /// Returns whether all recompilations succeeded.
+  Future<bool> _recompileDownstream(Iterable<StylesheetNode> nodes) async {
     var seen = new Set<StylesheetNode>();
     var toRecompile = new Queue.of(nodes);
 
+    var allSucceeded = true;
     while (!toRecompile.isEmpty) {
       var node = toRecompile.removeFirst();
       if (!seen.add(node)) continue;
 
-      await _compileIfEntrypoint(node.canonicalUrl);
+      var success = await _compileIfEntrypoint(node.canonicalUrl);
+      allSucceeded = allSucceeded && success;
+      if (!success && _options.stopOnError) return false;
+
       toRecompile.addAll(node.downstream);
     }
+    return allSucceeded;
   }
 
   /// Compiles the stylesheet at [url] to CSS if it's an entrypoint that's being
   /// watched.
-  Future _compileIfEntrypoint(Uri url) async {
-    if (url.scheme != 'file') return;
+  ///
+  /// Returns `false` if compilation failed, `true` otherwise.
+  Future<bool> _compileIfEntrypoint(Uri url) async {
+    if (url.scheme != 'file') return true;
 
     var source = p.fromUri(url);
     var destination = _destinationFor(source);
-    if (destination == null) return;
+    if (destination == null) return true;
 
-    await compile(source, destination);
+    return await compile(source, destination);
   }
 
   /// If a Sass file at [source] should be compiled to CSS, returns the path to
@@ -223,7 +250,9 @@ class _Watcher {
   /// Re-runs all imports in [_graph] that might refer to [path], and recompiles
   /// the files that contain those imports if they end up importing new
   /// stylesheets.
-  Future _retryPotentialImports(String path) async {
+  ///
+  /// Returns whether all recompilations succeeded.
+  Future<bool> _retryPotentialImports(String path) async {
     var name = _name(p.basename(path));
     var changed = <StylesheetNode>[];
     for (var node in _graph.nodes.values) {
@@ -250,7 +279,7 @@ class _Watcher {
       if (importChanged) changed.add(node);
     }
 
-    await _recompileDownstream(changed);
+    return await _recompileDownstream(changed);
   }
 
   /// Removes an extension from [extension], and a leading underscore if it has one.

lib/src/io/node.dart

@@ -263,7 +263,9 @@ Future<Stream<WatchEvent>> watchDir(String path, {bool poll: false}) {
 
   var completer = new Completer<Stream<WatchEvent>>();
   watcher.on('ready', allowInterop(() {
-    controller = new StreamController<WatchEvent>();
+    controller = new StreamController<WatchEvent>(onCancel: () {
+      watcher.close();
+    });
     completer.complete(controller.stream);
   }));
 

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.8.0-dev
+version: 1.8.0
 description: A Sass implementation in Dart.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/sass/dart-sass

test/cli/shared/colon_args.dart

@@ -68,6 +68,41 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
     await d.file("out2.css.map", contains("test2.scss")).validate();
   });
 
+  test("continues compiling after an error", () async {
+    await d.file("test1.scss", "a {b: }").create();
+    await d.file("test2.scss", "x {y: z}").create();
+
+    var sass = await runSass(
+        ["--no-source-map", "test1.scss:out1.css", "test2.scss:out2.css"]);
+    await expectLater(sass.stderr, emits('Error: Expected expression.'));
+    await expectLater(sass.stderr, emitsThrough(contains('test1.scss 1:7')));
+    await sass.shouldExit(65);
+
+    await d.nothing("out1.css").validate();
+    await d
+        .file("out2.css", equalsIgnoringWhitespace("x { y: z; }"))
+        .validate();
+  });
+
+  test("stops compiling after an error with --stop-on-error", () async {
+    await d.file("test1.scss", "a {b: }").create();
+    await d.file("test2.scss", "x {y: z}").create();
+
+    var sass = await runSass(
+        ["--stop-on-error", "test1.scss:out1.css", "test2.scss:out2.css"]);
+    await expectLater(
+        sass.stderr,
+        emitsInOrder([
+          'Error: Expected expression.',
+          emitsThrough(contains('test1.scss 1:7')),
+          emitsDone
+        ]));
+    await sass.shouldExit(65);
+
+    await d.nothing("out1.css").validate();
+    await d.nothing("out2.css").validate();
+  });
+
   group("with a directory argument", () {
     test("compiles all the stylesheets in the directory", () async {
       await d.dir("in", [

test/cli/shared/watch.dart

@@ -64,6 +64,48 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
 
           await d.file("out.css", "x {y: z}").validate();
         });
+
+        test("continues compiling after an error", () async {
+          await d.file("test1.scss", "a {b: }").create();
+          await d.file("test2.scss", "x {y: z}").create();
+
+          var sass =
+              await watch(["test1.scss:out1.css", "test2.scss:out2.css"]);
+          await expectLater(sass.stderr, emits('Error: Expected expression.'));
+          await expectLater(
+              sass.stderr, emitsThrough(contains('test1.scss 1:7')));
+          await expectLater(
+              sass.stdout, emitsThrough('Compiled test2.scss to out2.css.'));
+          await expectLater(sass.stdout, _watchingForChanges);
+          await sass.kill();
+
+          await d.nothing("out1.css").validate();
+          await d
+              .file("out2.css", equalsIgnoringWhitespace("x { y: z; }"))
+              .validate();
+        });
+
+        test("stops compiling after an error with --stop-on-error", () async {
+          await d.file("test1.scss", "a {b: }").create();
+          await d.file("test2.scss", "x {y: z}").create();
+
+          var sass = await watch([
+            "--stop-on-error",
+            "test1.scss:out1.css",
+            "test2.scss:out2.css"
+          ]);
+          await expectLater(
+              sass.stderr,
+              emitsInOrder([
+                'Error: Expected expression.',
+                emitsThrough(contains('test1.scss 1:7')),
+                emitsDone
+              ]));
+          await sass.shouldExit(65);
+
+          await d.nothing("out1.css").validate();
+          await d.nothing("out2.css").validate();
+        });
       });
 
       group("recompiles a watched file", () {
@@ -168,6 +210,28 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
           await d.nothing("out.css").validate();
         });
 
+        test("stops compiling after an error with --stop-on-error", () async {
+          await d.file("test.scss", "a {b: c}").create();
+
+          var sass = await watch(["--stop-on-error", "test.scss:out.css"]);
+          await expectLater(
+              sass.stdout, emits('Compiled test.scss to out.css.'));
+          await expectLater(sass.stdout, _watchingForChanges);
+          await tickIfPoll();
+
+          await d.file("test.scss", "a {b: }").create();
+          await expectLater(
+              sass.stderr,
+              emitsInOrder([
+                'Error: Expected expression.',
+                emitsThrough(contains('test.scss 1:7')),
+                emitsDone
+              ]));
+          await sass.shouldExit(65);
+
+          await d.nothing("out.css").validate();
+        });
+
         group("when its dependency is deleted", () {
           test("and removes the output", () async {
             await d.file("_other.scss", "a {b: c}").create();