Validate flutter.yaml against a JSON schema

examples/stocks/flutter.yaml

 name: stocks
-version: 0.0.2
-update-url: http://localhost:9888/
 uses-material-design: true

packages/flutter_tools/lib/src/flx.dart

@@ -8,6 +8,7 @@ import 'dart:io';
 
 import 'package:flx/bundle.dart';
 import 'package:flx/signing.dart';
+import 'package:json_schema/json_schema.dart';
 import 'package:path/path.dart' as path;
 import 'package:yaml/yaml.dart';
 
@@ -108,6 +109,20 @@ dynamic _loadManifest(String manifestPath) {
   return loadYaml(manifestDescriptor);
 }
 
+Future<int> _validateManifest(Object manifest) async {
+  String schemaPath = path.join(path.absolute(ArtifactStore.flutterRoot),
+      'packages', 'flutter_tools', 'schema', 'flutter_yaml.json');
+  Schema schema = await Schema.createSchemaFromUrl('file://$schemaPath');
+
+  Validator validator = new Validator(schema);
+  if (validator.validate(manifest))
+    return 0;
+
+  printError('Error in flutter.yaml:');
+  printError(validator.errors.join('\n'));
+  return 1;
+}
+
 ZipEntry _createAssetEntry(_Asset asset) {
   String source = asset.source ?? asset.key;
   File file = new File('${asset.base}/$source');
@@ -184,7 +199,14 @@ Future<int> build(
   String workingDirPath: defaultWorkingDirPath,
   bool precompiledSnapshot: false
 }) async {
-  Map<String, dynamic> manifestDescriptor = _loadManifest(manifestPath);
+  Object manifest = _loadManifest(manifestPath);
+  if (manifest != null) {
+    int result = await _validateManifest(manifest);
+    if (result != 0)
+      return result;
+  }
+  Map<String, dynamic> manifestDescriptor = manifest;
+
   String assetBasePath = path.dirname(path.absolute(manifestPath));
 
   File snapshotFile;

packages/flutter_tools/pubspec.yaml

@@ -14,6 +14,7 @@ dependencies:
   crypto: ^0.9.2
   den_api: ^0.1.0
   file: ^0.1.0
+  json_schema: ^1.0.3
   mustache4dart: ^1.0.0
   path: ^1.3.0
   pub_semver: ^1.0.0

packages/flutter_tools/schema/flutter_yaml.json

+{
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "title": "flutter.yaml",
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {
+        "name": { "type": "string" },
+        "uses-material-design": { "type": "boolean" },
+        "assets": {
+            "type": "array",
+            "items": { "type": "string" }
+        },
+        "fonts": {
+            "type": "array",
+            "items": {
+                "type": "object",
+                "additionalProperties": false,
+                "properties": {
+                    "family": { "type": "string" },
+                    "fonts": {
+                        "type": "array",
+                        "items": {
+                            "type": "object",
+                            "additionalProperties": false,
+                            "properties": {
+                                "asset": { "type": "string" },
+                                "weight": { "type": "integer" },
+                                "style": { "enum": [ "normal", "italic" ] }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}