Add git shorthand for dependencies

Author: greglittlefield-wf

benchmark/dart2js_output.dart

@@ -1,11 +1,11 @@
-import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/command_runner.dart';
 import 'package:meta/meta.dart';
 
 import 'dart2js_output/compile.dart';
 import 'dart2js_output/dart2js_normalize.dart';
+import 'dart2js_output/dependency.dart';
 import 'dart2js_output/logging.dart';
 import 'dart2js_output/source.dart' as source;
 
@@ -21,16 +21,6 @@ Future<void> main(List<String> args) async {
   await runner.run(args);
 }
 
-final _originMasterDep = jsonEncode({
-  'git': {
-    'url': Directory.current.uri.toString(),
-    'ref': 'origin/HEAD',
-  }
-});
-final _localPathDep = jsonEncode({
-  'path': Directory.current.path,
-});
-
 abstract class BaseCommand extends Command {
   BaseCommand() {
     argParser.addFlag('verbose', defaultsTo: true, negatable: true);
@@ -48,20 +38,21 @@ abstract class CompareCommand extends BaseCommand {
     argParser.addOption(
       'head',
       help: 'Head over_react dependency to compare to the base.'
+          ' Supports dependencies entry in JSON format, or `git:<ref>` shorthand.'
           ' Defaults to the enclosing local working copy of over_react.',
-      defaultsTo: _localPathDep,
+      defaultsTo: localPathDepString,
     );
     argParser.addOption(
       'base',
       help: 'Base over_react dependency to compare against.'
-          ' Defaults to origin/master.',
-      defaultsTo: _originMasterDep,
+          ' Supports dependencies entry in JSON format, or `git:<ref>` shorthand.',
+      defaultsTo: originHeadDepString,
     );
   }
 
-  dynamic get _baseDep => jsonDecode(argResults!['base'] as String);
+  dynamic get _baseDep => parseDependency(argResults!['base'] as String);
 
-  dynamic get _headDep => jsonDecode(argResults!['head'] as String);
+  dynamic get _headDep => parseDependency(argResults!['head'] as String);
 }
 
 class CompareSizeCommand extends CompareCommand {
@@ -128,12 +119,13 @@ class GetCodeCommand extends BaseCommand {
     argParser.addOption(
       'dependency',
       help: 'over_react dependency to compile with.'
+          ' Supports dependencies entry in JSON format, or `git:<ref>` shorthand.'
           ' Defaults to the enclosing local working copy of over_react.',
-      defaultsTo: _localPathDep,
+      defaultsTo: localPathDepString,
     );
   }
 
-  dynamic get _dep => jsonDecode(argResults!['dependency'] as String);
+  dynamic get _dep => parseDependency(argResults!['dependency'] as String);
 
   @override
   Future<void> run() async {

benchmark/dart2js_output/dependency.dart

@@ -0,0 +1,25 @@
+import 'dart:convert';
+import 'dart:io';
+
+const originHeadDepString = 'git:origin/HEAD';
+final localPathDepString = jsonEncode({
+  'path': Directory.current.path,
+});
+
+dynamic parseDependency(String dependency) {
+  final gitShorthandMatch = RegExp(r'^git:(.+)$').matchAsPrefix(dependency);
+  if (gitShorthandMatch != null) {
+    return {
+      'git': {
+        'url': Directory.current.uri.toString(),
+        'ref': gitShorthandMatch.group(1)!,
+      }
+    };
+  }
+  try {
+    return jsonDecode(dependency);
+  } catch (e) {
+    throw ArgumentError.value(
+        dependency, 'dependency', 'must be a valid JSON String or a git:<ref> shorthand');
+  }
+}