support resolving .packages in FE

pkg/front_end/test/src/base/processed_options_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/base/processed_options.dart';
 import 'package:front_end/src/fasta/fasta.dart' show ByteSink;
+import 'package:front_end/src/fasta/fasta_codes.dart';
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
 import 'package:kernel/kernel.dart' show Program, Library, CanonicalName;
+import 'package:package_config/packages.dart' show Packages;
 
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(ProcessedOptionsTest);
   });
 }
 
 @reflectiveTest
 class ProcessedOptionsTest {
-  final fileSystem = new MemoryFileSystem(Uri.parse('file:///'));
+  MemoryFileSystem fileSystem = new MemoryFileSystem(Uri.parse('file:///'));
 
   Program _mockOutline;
 
   Program get mockSummary => _mockOutline ??=
       new Program(libraries: [new Library(Uri.parse('file:///a/b.dart'))]);
 
   test_compileSdk_false() {
     for (var value in [false, true]) {
       var raw = new CompilerOptions()..compileSdk = value;
       var processed = new ProcessedOptions(raw);
@@ skipping 39 matching lines @@
     fileSystem.entityForUri(uri).writeAsBytesSync(sink.builder.takeBytes());
   }
 
   Future<Null> checkMockSummary(CompilerOptions raw) async {
     var processed = new ProcessedOptions(raw);
     var sdkSummary = await processed.loadSdkSummary(new CanonicalName.root());
     expect(sdkSummary.libraries.single.importUri,
         mockSummary.libraries.single.importUri);
   }
 
+  checkPackageExpansion(
+      String packageName, String packageDir, Packages packages) {
+    var input = Uri.parse('package:$packageName/a.dart');
+    var expected = Uri.parse('file:///$packageDir/a.dart');

[ahe, 2017/07/14 13:44:58]

Is this a real file or a fake URI?

[Siggi Cherem (dart-lang), 2017/07/14 19:54:07]

All fake. Tracked in https://github.com/dart-lang/sdk/issues/30141

+    expect(packages.resolve(input), expected);
+  }
+
   test_getUriTranslator_explicitPackagesFile() async {
     // This .packages file should be ignored.
     fileSystem
         .entityForUri(Uri.parse('file:///.packages'))
         .writeAsStringSync('foo:bar\n');
     // This one should be used.
     fileSystem
         .entityForUri(Uri.parse('file:///explicit.packages'))
         .writeAsStringSync('foo:baz\n');
     var raw = new CompilerOptions()
       ..fileSystem = fileSystem
       ..packagesFileUri = Uri.parse('file:///explicit.packages');
     var processed = new ProcessedOptions(raw);
     var uriTranslator = await processed.getUriTranslator();
-    expect(uriTranslator.packages, {'foo': Uri.parse('file:///baz/')});
+    checkPackageExpansion('foo', 'baz', uriTranslator.packages);
   }
 
   test_getUriTranslator_explicitPackagesFile_withBaseLocation() async {
     // This .packages file should be ignored.
     fileSystem
         .entityForUri(Uri.parse('file:///.packages'))
         .writeAsStringSync('foo:bar\n');
     // This one should be used.
     fileSystem
         .entityForUri(Uri.parse('file:///base/location/explicit.packages'))
         .writeAsStringSync('foo:baz\n');
     var raw = new CompilerOptions()
       ..fileSystem = fileSystem
       ..packagesFileUri = Uri.parse('file:///base/location/explicit.packages');
     var processed = new ProcessedOptions(raw);
     var uriTranslator = await processed.getUriTranslator();
-    expect(uriTranslator.packages,
-        {'foo': Uri.parse('file:///base/location/baz/')});
+    checkPackageExpansion('foo', 'base/location/baz', uriTranslator.packages);
+  }
+
+  test_getUriTranslator_implicitPackagesFile_ambiguous() async {
+    // This .packages file should be ignored.
+    fileSystem
+        .entityForUri(Uri.parse('file:///.packages'))

[ahe, 2017/07/14 13:44:58]

Use custom URI.

I don't like seeing error messages like this:

file:///file:///test-lib:4:11: Error: Expected an expression, but got '...'.
  int y = ......;
          ^

They're really confusing compared to:

org-dartlang-memory-filesystem:///test-lib:4:11: Error: Expected an expression,
but got '...'.
  int y = ......;
          ^

It's also hard to debug who's causing the URI to have a path that starts with
file:.

[Siggi Cherem (dart-lang), 2017/07/14 19:54:06]

tracking here https://github.com/dart-lang/sdk/issues/30141

+        .writeAsStringSync('foo:bar\n');
+    // This one should be used.
+    fileSystem
+        .entityForUri(Uri.parse('file:///explicit.packages'))
+        .writeAsStringSync('foo:baz\n');
+    var raw = new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..packagesFileUri = Uri.parse('file:///explicit.packages');
+    var processed = new ProcessedOptions(raw);
+    var uriTranslator = await processed.getUriTranslator();
+    checkPackageExpansion('foo', 'baz', uriTranslator.packages);
+  }
+
+  test_getUriTranslator_implicitPackagesFile_nextToScript() async {
+    // Fake the existence of the base directory.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/'))
+        .writeAsStringSync('');
+    // Packages directory should be ignored (.packages file takes precedence).
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/packages/'))
+        .writeAsStringSync('');
+    // This .packages file should be ignored.
+    fileSystem
+        .entityForUri(Uri.parse('file:///.packages'))
+        .writeAsStringSync('foo:bar\n');
+    // This one should be used.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/.packages'))
+        .writeAsStringSync('foo:baz\n');
+    var raw = new CompilerOptions()..fileSystem = fileSystem;
+    var processed = new ProcessedOptions(
+        raw, false, [Uri.parse('file:///base/location/script.dart')]);
+    var uriTranslator = await processed.getUriTranslator();
+    checkPackageExpansion('foo', 'base/location/baz', uriTranslator.packages);
+  }
+
+  test_getUriTranslator_implicitPackagesFile_searchAbove() async {
+    // Fake the existence of the base directory.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/'))
+        .writeAsStringSync('');
+    // This .packages file should be ignored.
+    fileSystem
+        .entityForUri(Uri.parse('file:///.packages'))
+        .writeAsStringSync('foo:bar\n');
+    // This one should be used.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/.packages'))
+        .writeAsStringSync('foo:baz\n');
+    var raw = new CompilerOptions()..fileSystem = fileSystem;
+    var processed = new ProcessedOptions(
+        raw, false, [Uri.parse('file:///base/location/script.dart')]);
+    var uriTranslator = await processed.getUriTranslator();
+    checkPackageExpansion('foo', 'base/baz', uriTranslator.packages);
+  }
+
+  test_getUriTranslator_implicitPackagesFile_packagesDirectory() async {
+    // Fake the existence of the base directory.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/'))
+        .writeAsStringSync('');
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/packages/'))
+        .writeAsStringSync('');
+
+    // Both of these .packages file should be ignored.
+    fileSystem
+        .entityForUri(Uri.parse('file:///.packages'))
+        .writeAsStringSync('foo:bar\n');
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/.packages'))
+        .writeAsStringSync('foo:baz\n');
+    var raw = new CompilerOptions()..fileSystem = fileSystem;
+    var processed = new ProcessedOptions(
+        raw, false, [Uri.parse('file:///base/location/script.dart')]);
+    var uriTranslator = await processed.getUriTranslator();
+    checkPackageExpansion(
+        'foo', 'base/location/packages/foo', uriTranslator.packages);
+  }
+
+  test_getUriTranslator_implicitPackagesFile_noPackages() async {
+    // Fake the existence of the base directory.
+    fileSystem
+        .entityForUri(Uri.parse('file:///base/location/'))
+        .writeAsStringSync('');
+    var errors = [];
+    // .packages file should be ignored.
+    var raw = new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..onError = (e) => errors.add(e);
+    var processed = new ProcessedOptions(
+        raw, false, [Uri.parse('file:///base/location/script.dart')]);
+    var uriTranslator = await processed.getUriTranslator();
+    expect(errors, isEmpty);
+    expect(uriTranslator.packages.asMap(), isEmpty);
   }
 
   test_getUriTranslator_noPackages() async {
+    var errors = [];
     // .packages file should be ignored.
     fileSystem
         .entityForUri(Uri.parse('file:///.packages'))
         .writeAsStringSync('foo:bar\n');
     var raw = new CompilerOptions()
       ..fileSystem = fileSystem
-      ..packagesFileUri = new Uri();
+      ..packagesFileUri = new Uri()
+      ..onError = (e) => errors.add(e);
     var processed = new ProcessedOptions(raw);
     var uriTranslator = await processed.getUriTranslator();
-    expect(uriTranslator.packages, isEmpty);
+    expect(uriTranslator.packages.asMap(), isEmpty);
+    expect(errors.single.message,
+        startsWith(_stringPrefixOf(templateInvalidPackagesFile)));
+  }
+
+  test_validateOptions_noInputs() async {
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
+    var errors = [];
+    var raw = new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..onError = (e) => errors.add(e);
+    var options = new ProcessedOptions(raw);
+    var result = await options.validateOptions();
+    expect(errors.single.message, messageMissingInputs.message);
+    expect(result, isFalse);
+  }
+
+  test_validateOptions_input_doesnt_exist() async {
+    var errors = [];
+    var raw = new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..onError = (e) => errors.add(e);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
+    var result = await options.validateOptions();
+    expect(errors.single.message,
+        startsWith(_stringPrefixOf(templateMissingInputFile)));
+    expect(result, isFalse);
   }
 
   test_validateOptions_root_exists() async {
     var sdkRoot = Uri.parse('file:///sdk/root/');
     fileSystem
         // Note: this test is a bit hackish because the memory file system
         // doesn't have the notion of directories.
         .entityForUri(sdkRoot)
         .writeAsStringSync('\n');
     fileSystem
         .entityForUri(sdkRoot.resolve('outline.dill'))
         .writeAsStringSync('\n');
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
 
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkRoot = sdkRoot
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     var result = await options.validateOptions();
     // Note: we check this first so test failures show the cause directly.
     expect(errors, isEmpty);
     expect(result, isTrue);
   }
 
   test_validateOptions_root_doesnt_exists() async {
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
     var sdkRoot = Uri.parse('file:///sdk/root');
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkRoot = sdkRoot
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     expect(await options.validateOptions(), isFalse);
-    expect(errors.first.message, contains("SDK root directory not found"));
+    expect(errors.first.message,
+        startsWith(_stringPrefixOf(templateMissingSdkRoot)));
   }
 
   test_validateOptions_summary_exists() async {
     var sdkSummary = Uri.parse('file:///sdk/root/outline.dill');
     fileSystem.entityForUri(sdkSummary).writeAsStringSync('\n');
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
 
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkSummary = sdkSummary
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     var result = await options.validateOptions();
     expect(errors, isEmpty);
     expect(result, isTrue);
   }
 
   test_validateOptions_summary_doesnt_exists() async {
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
     var sdkSummary = Uri.parse('file:///sdk/root/outline.dill');
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkSummary = sdkSummary
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     expect(await options.validateOptions(), isFalse);
-    expect(errors.first.message, contains("SDK summary not found"));
+    expect(errors.single.message,
+        startsWith(_stringPrefixOf(templateMissingSdkSummary)));
   }
 
   test_validateOptions_inferred_summary_exists() async {
     var sdkRoot = Uri.parse('file:///sdk/root/');
     var sdkSummary = Uri.parse('file:///sdk/root/outline.dill');
     fileSystem.entityForUri(sdkRoot).writeAsStringSync('\n');
     fileSystem.entityForUri(sdkSummary).writeAsStringSync('\n');
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
 
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkRoot = sdkRoot
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     var result = await options.validateOptions();
     expect(errors, isEmpty);
     expect(result, isTrue);
   }
 
   test_validateOptions_inferred_summary_doesnt_exists() async {
     var sdkRoot = Uri.parse('file:///sdk/root/');
     var sdkSummary = Uri.parse('file:///sdk/root/outline.dill');
     fileSystem.entityForUri(sdkRoot).writeAsStringSync('\n');
+    fileSystem
+        .entityForUri(Uri.parse('file:///foo.dart'))
+        .writeAsStringSync('main(){}\n');
     var errors = [];
     var raw = new CompilerOptions()
       ..sdkSummary = sdkSummary
       ..fileSystem = fileSystem
       ..onError = (e) => errors.add(e);
-    var options = new ProcessedOptions(raw);
+    var options = new ProcessedOptions(raw, false, [Uri.parse('foo.dart')]);
     expect(await options.validateOptions(), isFalse);
-    expect(errors.first.message, contains("SDK summary not found"));
+    expect(errors.single.message,
+        startsWith(_stringPrefixOf(templateMissingSdkSummary)));
+  }
+
+  /// Returns the longest prefix of the text in a message template that doesn't
+  /// mention a template argument.
+  _stringPrefixOf(Template template) {
+    var messageTemplate = template.messageTemplate;
+    var index = messageTemplate.indexOf('#');
+    var prefix = messageTemplate.substring(0, index - 1);
+
+    // Check that the prefix is not empty and that it contains more than one
+    // word.
+    expect(prefix.length > 0, isTrue);
+    expect(prefix.contains(' '), isTrue);
+    return prefix;
   }
 }