Lots of bug fixes relating to failed builds and recovery from them

build/lib/src/builder/logging.dart

@@ -9,7 +9,27 @@ const Symbol logKey = #buildLog;
 /// Will be `null` when not running within a build.
 Logger get log => Zone.current[logKey] as Logger;
 
-T scopeLog<T>(T fn(), Logger log) => runZoned(fn, zoneSpecification:
-        new ZoneSpecification(print: (self, parent, zone, message) {
-      log.info(message);
-    }), zoneValues: {logKey: log});
+/// Runs [fn] in an error handling [Zone].
+///
+/// Any calls to [print] will be logged with `log.info`, and any errors will be
+/// logged with `log.severe`.
+///
+/// Completes with the first error or result of `fn`, whichever comes first.
+Future<T> scopeLogAsync<T>(Future<T> fn(), Logger log) {
+  var done = new Completer<T>();
+  runZoned(fn,
+      zoneSpecification:
+          new ZoneSpecification(print: (self, parent, zone, message) {
+        log.info(message);
+      }),
+      zoneValues: {logKey: log},
+      onError: (Object e, StackTrace s) {
+        log.severe('', e);
+        if (done.isCompleted) return;
+        done.completeError(e, s);
+      }).then((result) {
+    if (done.isCompleted) return;
+    done.complete(result);
+  });
+  return done.future;
+}

build/lib/src/generate/run_builder.dart

@@ -46,7 +46,7 @@ Future<Null> runBuilder(Builder builder, Iterable<AssetId> inputs,
     }
   }
 
-  await scopeLog(() => Future.wait(inputs.map(buildForInput)), logger);
+  await scopeLogAsync(() => Future.wait(inputs.map(buildForInput)), logger);
 
   if (shouldDisposeResourceManager) {
     await resourceManager.disposeAll();

build_compilers/lib/src/dev_compiler_builder.dart

@@ -40,9 +40,9 @@ class DevCompilerBuilder implements Builder {
     try {
       await createDevCompilerModule(module, buildStep);
     } on DartDevcCompilationException catch (e) {
-      log.warning('Error compiling ${module.jsId}:\n$e');
       await buildStep.writeAsString(
           buildStep.inputId.changeExtension(jsModuleErrorsExtension), '$e');
+      log.severe('', e);
     }
   }
 }

build_compilers/lib/src/modules.dart

@@ -116,9 +116,14 @@ class Module extends Object with _$ModuleSerializerMixin {
       var next = modulesToCrawl.last;
       modulesToCrawl.remove(next);
       if (transitiveDeps.containsKey(next)) continue;
-      var module = new Module.fromJson(JSON.decode(
-              await reader.readAsString(next.changeExtension(moduleExtension)))
-          as Map<String, dynamic>);
+      var nextModuleId = next.changeExtension(moduleExtension);
+      if (!await reader.canRead(nextModuleId)) {
+        log.warning('Missing module $nextModuleId');
+        continue;
+      }
+      var module = new Module.fromJson(
+          JSON.decode(await reader.readAsString(nextModuleId))
+              as Map<String, dynamic>);
       transitiveDeps[next] = module;
       modulesToCrawl.addAll(module.directDependencies);
     }

build_runner/lib/src/asset/reader.dart

@@ -35,16 +35,20 @@ class SinglePhaseReader implements AssetReader {
   Iterable<Glob> get globsRan => _globsRan;
 
   bool _isReadable(AssetId id) {
+    _assetsRead.add(id);
     var node = _assetGraph.get(id);
-    if (node == null) return false;
+    if (node == null) {
+      _assetGraph.add(new SyntheticAssetNode(id));
+      return false;
+    }
+    if (node is SyntheticAssetNode) return false;
     if (node is! GeneratedAssetNode) return true;
     return (node as GeneratedAssetNode).phaseNumber < _phaseNumber;
   }
 
   @override
   Future<bool> canRead(AssetId id) async {
     if (!_isReadable(id)) return new Future.value(false);
-    _assetsRead.add(id);
     await _ensureAssetIsBuilt(id);
     var node = _assetGraph.get(id);
     if (node is GeneratedAssetNode) {
@@ -59,15 +63,13 @@ class SinglePhaseReader implements AssetReader {
   @override
   Future<List<int>> readAsBytes(AssetId id) async {
     if (!_isReadable(id)) throw new AssetNotFoundException(id);
-    _assetsRead.add(id);
     await _ensureAssetIsBuilt(id);
     return _delegate.readAsBytes(id);
   }
 
   @override
   Future<String> readAsString(AssetId id, {Encoding encoding: UTF8}) async {
     if (!_isReadable(id)) throw new AssetNotFoundException(id);
-    _assetsRead.add(id);
     await _ensureAssetIsBuilt(id);
     return _delegate.readAsString(id, encoding: encoding);
   }

build_runner/lib/src/asset_graph/graph.dart

@@ -60,10 +60,17 @@ class AssetGraph {
   ///
   /// Throws a [StateError] if it already exists in the graph.
   void _add(AssetNode node) {
-    if (contains(node.id)) {
-      throw new StateError(
-          'Tried to add node ${node.id} to the asset graph but it already '
-          'exists.');
+    var existing = get(node.id);
+    if (existing != null) {
+      if (existing is SyntheticAssetNode) {
+        _remove(existing.id);
+        node.outputs.addAll(existing.outputs);
+        node.primaryOutputs.addAll(existing.primaryOutputs);
+      } else {
+        throw new StateError(
+            'Tried to add node ${node.id} to the asset graph but it already '
+            'exists.');
+      }
     }
     _nodesByPackage.putIfAbsent(node.id.package, () => {})[node.id.path] = node;
   }
@@ -84,8 +91,9 @@ class AssetGraph {
       allNodes.where((n) => n is GeneratedAssetNode).map((n) => n.id);
 
   /// All the source files in the graph.
-  Iterable<AssetId> get sources =>
-      allNodes.where((n) => n is! GeneratedAssetNode).map((n) => n.id);
+  Iterable<AssetId> get sources => allNodes
+      .where((n) => n is! GeneratedAssetNode && n is! SyntheticAssetNode)
+      .map((n) => n.id);
 
   /// Updates graph structure, invalidating and deleting any outputs that were
   /// affected.
@@ -105,31 +113,32 @@ class AssetGraph {
     // Builds up `idsToDelete` and `idsToRemove` by recursively invalidating
     // the outputs of `id`.
     void clearNodeAndDeps(AssetId id, ChangeType rootChangeType,
-        {AssetId parent, bool rootIsSource}) {
+        {bool rootIsSource}) {
       var node = this.get(id);
       if (node == null) return;
       if (!invalidatedIds.add(id)) return;
-      if (parent == null) rootIsSource = node is! GeneratedAssetNode;
-
-      // Update all outputs of this asset as well.
-      for (var output in node.outputs) {
-        clearNodeAndDeps(output, rootChangeType,
-            parent: node.id, rootIsSource: rootIsSource);
-      }
+      rootIsSource ??= node is! GeneratedAssetNode;
 
       if (node is GeneratedAssetNode) {
         idsToDelete.add(id);
         if (rootIsSource &&
             rootChangeType == ChangeType.REMOVE &&
-            node.primaryInput == parent) {
+            idsToRemove.contains(node.primaryInput)) {
           idsToRemove.add(id);
         } else {
           node.needsUpdate = true;
+          node.wasOutput = false;
+          node.globs = new Set();
         }
       } else {
         // This is a source
         if (rootChangeType == ChangeType.REMOVE) idsToRemove.add(id);
       }
+
+      // Update all outputs of this asset as well.
+      for (var output in node.outputs) {
+        clearNodeAndDeps(output, rootChangeType, rootIsSource: rootIsSource);
+      }
     }
 
     updates.forEach(clearNodeAndDeps);

build_runner/lib/src/asset_graph/node.dart

@@ -23,6 +23,18 @@ class AssetNode {
   String toString() => 'AssetNode: $id';
 }
 
+/// A node which is not a generated or source asset.
+///
+/// Typically these are created as a result of `canRead` calls for assets that
+/// don't exist in the graph. We still need to set up proper dependencies so
+/// that if that asset gets added later the outputs are properly invalidated.
+class SyntheticAssetNode extends AssetNode {
+  SyntheticAssetNode(AssetId id) : super(id);
+
+  @override
+  String toString() => 'SyntheticAssetNode: $id';
+}
+
 /// A generated node in the asset graph.
 class GeneratedAssetNode extends AssetNode {
   /// The phase which generated this asset.

build_runner/lib/src/asset_graph/serialization.dart

@@ -8,7 +8,7 @@ part of 'graph.dart';
 ///
 /// This should be incremented any time the serialize/deserialize formats
 /// change.
-const _version = 7;
+const _version = 8;
 
 /// Deserializes an [AssetGraph] from a [Map].
 class _AssetGraphDeserializer {
@@ -43,16 +43,21 @@ class _AssetGraphDeserializer {
 
   AssetNode _deserializeAssetNode(List serializedNode) {
     AssetNode node;
-    if (serializedNode.length == 3) {
-      node = new AssetNode(_idToAssetId[serializedNode[0]]);
-    } else if (serializedNode.length == 8) {
+    var id = _idToAssetId[serializedNode[0]];
+    if (serializedNode.length == 4) {
+      if (_deserializeBool(serializedNode[3] as int)) {
+        node = new SyntheticAssetNode(id);
+      } else {
+        node = new AssetNode(id);
+      }
+    } else if (serializedNode.length == 9) {
       node = new GeneratedAssetNode(
-        serializedNode[5] as int,
-        _idToAssetId[serializedNode[3]],
-        _deserializeBool(serializedNode[7] as int),
-        _deserializeBool(serializedNode[4] as int),
-        _idToAssetId[serializedNode[0]],
-        globs: (serializedNode[6] as Iterable<String>)
+        serializedNode[6] as int,
+        _idToAssetId[serializedNode[4]],
+        _deserializeBool(serializedNode[8] as int),
+        _deserializeBool(serializedNode[5] as int),
+        id,
+        globs: (serializedNode[7] as Iterable<String>)
             .map((pattern) => new Glob(pattern))
             .toSet(),
       );
@@ -125,7 +130,7 @@ class _WrappedAssetNode extends Object with ListMixin implements List {
   _WrappedAssetNode(this.node, this.serializer);
 
   @override
-  int get length => 3;
+  int get length => 4;
   @override
   set length(_) => throw new UnsupportedError(
       'length setter not unsupported for WrappedAssetNode');
@@ -141,6 +146,8 @@ class _WrappedAssetNode extends Object with ListMixin implements List {
         return node.primaryOutputs
             .map((id) => serializer._assetIdToId[id])
             .toList();
+      case 3:
+        return _serializeBool(node is SyntheticAssetNode);
       default:
         throw new RangeError.index(index, this);
     }
@@ -167,22 +174,22 @@ class _WrappedGeneratedAssetNode extends _WrappedAssetNode {
   Object operator [](int index) {
     if (index < super.length) return super[index];
     switch (index) {
-      case 3:
+      case 4:
         return generatedNode.primaryInput != null
             ? serializer._assetIdToId[generatedNode.primaryInput]
             : null;
-      case 4:
-        return _serializeBool(generatedNode.wasOutput);
       case 5:
-        return generatedNode.phaseNumber;
+        return _serializeBool(generatedNode.wasOutput);
       case 6:
-        return generatedNode.globs.map((glob) => glob.pattern).toList();
+        return generatedNode.phaseNumber;
       case 7:
+        return generatedNode.globs.map((glob) => glob.pattern).toList();
+      case 8:
         return _serializeBool(generatedNode.needsUpdate);
       default:
         throw new RangeError.index(index, this);
     }
   }
-
-  static int _serializeBool(bool value) => value ? 1 : 0;
 }
+
+int _serializeBool(bool value) => value ? 1 : 0;

build_runner/lib/src/generate/build_definition.dart

@@ -153,12 +153,17 @@ class _Loader {
       }
     }
 
-    var newSources = inputSources
-        .difference(assetGraph.allNodes.map((node) => node.id).toSet());
+    var newSources = inputSources.difference(assetGraph.allNodes
+        .where((node) => node is! SyntheticAssetNode)
+        .map((node) => node.id)
+        .toSet());
     addUpdates(newSources, ChangeType.ADD);
     var removedAssets = assetGraph.allNodes
-        .where((n) =>
-            n is! GeneratedAssetNode || (n as GeneratedAssetNode).wasOutput)
+        .where((n) {
+          if (n is SyntheticAssetNode) return false;
+          if (n is GeneratedAssetNode) return n.wasOutput;
+          return true;
+        })
         .map((n) => n.id)
         .where((id) => !allSources.contains((id)));
 

build_runner/lib/src/generate/build_impl.dart

@@ -227,6 +227,7 @@ class BuildImpl {
     var ids = new Set<AssetId>();
     await Future
         .wait(_assetGraph.packageNodes(inputSet.package).map((node) async {
+      if (node is SyntheticAssetNode) return;
       if (!inputSet.matches(node.id)) return;
       if (node is GeneratedAssetNode) {
         if (node.phaseNumber >= phaseNumber) return;
@@ -310,8 +311,9 @@ class BuildImpl {
         input.package,
         (phase, input) => _runLazyPhaseForInput(phase, input, resourceManager));
     var wrappedWriter = new AssetWriterSpy(_writer);
+    var logger = new Logger('$builder on $input');
     await runBuilder(builder, [input], wrappedReader, wrappedWriter, _resolvers,
-        resourceManager: resourceManager);
+        logger: logger, resourceManager: resourceManager);
 
     // Reset the state for all the `builderOutputs` nodes based on what was
     // read and written.
@@ -339,11 +341,15 @@ class BuildImpl {
         (phase, input) => _runLazyPhaseForInput(phase, input, resourceManager));
     var wrappedWriter = new AssetWriterSpy(_writer);
 
-    var logger = new Logger('runBuilder');
+    var logger = new Logger('$builder on $package');
     var buildStep = new BuildStepImpl(null, builderOutputs, wrappedReader,
         wrappedWriter, _packageGraph.root.name, _resolvers, resourceManager);
     try {
-      await scopeLog(() => builder.build(buildStep), logger);
+      // Wrapping in `new Future.value` to work around
+      // https://github.com/dart-lang/sdk/issues/31237, users might return
+      // synchronously and not have any analysis errors today.
+      await scopeLogAsync(
+          () => new Future.value(builder.build(buildStep)), logger);
     } finally {
       await buildStep.complete();
     }