Use messages for (some) public API errors

not entirely ready - looking for comments.

BUG=
[email protected]

Review-Url: https://codereview.chromium.org/2979623002 .

Author: sigmundch

pkg/front_end/lib/compilation_error.dart

@@ -9,18 +9,20 @@ library front_end.compilation_error;
 import 'package:source_span/source_span.dart' show SourceSpan;
 
 /// A single error that occurred during compilation, and information about where
-/// it occurred.
+/// it occurred and how to fix it.
 ///
 /// TODO(paulberry): add a reference to the analyzer error code.
 ///
 /// Not intended to be implemented or extended by clients.
+// TODO(sigmund): rename to CompliationMessage
 abstract class CompilationError {
-  /// A text description of how the user can fix the error.  May be `null`.
-  String get correction;
+  /// A text description of the compile error.
+  String get message;
+
+  /// A suggestion for the user to hint them on how to fix the error. May be
+  /// `null`.
+  String get tip;
 
   /// The source span where the error occurred.
   SourceSpan get span;
-
-  /// A text description of the compile error.
-  String get message;
 }

pkg/front_end/lib/kernel_generator.dart

@@ -12,6 +12,7 @@ import 'package:kernel/kernel.dart' show Program;
 
 import 'compiler_options.dart';
 import 'src/base/processed_options.dart';
+import 'src/fasta/fasta_codes.dart';
 import 'src/kernel_generator_impl.dart';
 
 /// Generates a kernel representation of the program whose main library is in
@@ -40,7 +41,7 @@ Future<Program> kernelForProgram(Uri source, CompilerOptions options) async {
   if (program == null) return null;
 
   if (program.mainMethod == null) {
-    pOptions.reportError("No 'main' method found.");
+    pOptions.reportMessage(messageMissingMain.withLocation(source, -1));
     return null;
   }
 

pkg/front_end/lib/src/base/processed_options.dart

@@ -8,17 +8,19 @@ import 'package:front_end/compilation_error.dart';
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/file_system.dart';
 import 'package:front_end/src/base/performace_logger.dart';
+import 'package:front_end/src/fasta/fasta_codes.dart';
 import 'package:front_end/src/fasta/ticker.dart';
 import 'package:front_end/src/fasta/uri_translator.dart';
 import 'package:front_end/src/fasta/uri_translator_impl.dart';
+import 'package:front_end/src/fasta/problems.dart' show unimplemented;
 import 'package:front_end/src/incremental/byte_store.dart';
 import 'package:front_end/src/multi_root_file_system.dart';
 import 'package:kernel/kernel.dart'
     show Program, loadProgramFromBytes, CanonicalName;
 import 'package:kernel/target/targets.dart';
 import 'package:kernel/target/vm_fasta.dart';
 import 'package:package_config/packages_file.dart' as package_config;
-import 'package:source_span/source_span.dart' show SourceSpan;
+import 'package:source_span/source_span.dart' show SourceSpan, SourceLocation;
 
 /// All options needed for the front end implementation.
 ///
@@ -111,38 +113,48 @@ class ProcessedOptions {
     return _raw.byteStore;
   }
 
-  // TODO(sigmund): delete. We should use messages with error codes directly
-  // instead.
-  void reportError(String message) {
-    _raw.onError(new _CompilationError(message));
+  // TODO(sigmund,ahe): delete in favor of reportMessage.
+  void deprecated_reportError(String error) {
+    _raw.onError(new _StringMessage(error));
   }
 
+  void reportMessage(LocatedMessage message) {
+    _raw.onError(new _CompilationMessage(message));
+  }
+
+  void reportMessageWithoutLocation(Message message) =>
+      reportMessage(message.withLocation(null, -1));
+
   /// Runs various validations checks on the input options. For instance,
   /// if an option is a path to a file, it checks that the file exists.
   Future<bool> validateOptions() async {
     for (var source in inputs) {
       if (source.scheme == 'file' &&
           !await fileSystem.entityForUri(source).exists()) {
-        reportError("Entry-point file not found: $source");
+        reportMessageWithoutLocation(
+            templateMissingInputFile.withArguments('$source'));
         return false;
       }
     }
 
     if (_raw.sdkRoot != null &&
         !await fileSystem.entityForUri(sdkRoot).exists()) {
-      reportError("SDK root directory not found: ${sdkRoot}");
+      reportMessageWithoutLocation(
+          templateMissingSdkRoot.withArguments('$sdkRoot'));
       return false;
     }
 
     var summary = sdkSummary;
     if (summary != null && !await fileSystem.entityForUri(summary).exists()) {
-      reportError("SDK summary not found: ${summary}");
+      reportMessageWithoutLocation(
+          templateMissingSdkSummary.withArguments('$summary'));
       return false;
     }
 
     if (compileSdk && summary != null) {
-      reportError(
-          "The compileSdk and sdkSummary options are mutually exclusive");
+      reportMessageWithoutLocation(
+          templateInternalProblemUnsupported.withArguments(
+              "The compileSdk and sdkSummary options are mutually exclusive"));
       return false;
     }
     return true;
@@ -245,7 +257,7 @@ class ProcessedOptions {
     if (_packages == null) {
       if (_raw.packagesFileUri == null) {
         // TODO(sigmund,paulberry): implement
-        throw new UnimplementedError('search for .packages');
+        return unimplemented('search for .packages');
       } else if (_raw.packagesFileUri.path.isEmpty) {
         _packages = {};
       } else {
@@ -265,7 +277,7 @@ class ProcessedOptions {
     if (_raw.sdkRoot == null) {
       // TODO(paulberry): implement the algorithm for finding the SDK
       // automagically.
-      throw new UnimplementedError('infer the default sdk location');
+      return unimplemented('infer the default sdk location');
     }
     var root = _raw.sdkRoot;
     if (!root.path.endsWith('/')) {
@@ -346,12 +358,30 @@ class HermeticAccessException extends FileSystemException {
   String toString() => message;
 }
 
-/// An error that only contains a message and no error location.
-class _CompilationError implements CompilationError {
-  String get correction => null;
-  SourceSpan get span => null;
+/// Wraps a [LocatedMessage] to implement the public [CompilationError] API.
+class _CompilationMessage implements CompilationError {
+  final LocatedMessage original;
+
+  String get message => original.message;
+
+  String get tip => original.tip;
+
+  SourceSpan get span =>
+      new SourceLocation(original.charOffset, sourceUrl: original.uri)
+          .pointSpan();
+
+  _CompilationMessage(this.original);
+
+  String toString() => message;
+}
+
+/// Wraps an error message as a [CompilationError] API.
+class _StringMessage implements CompilationError {
   final String message;
-  _CompilationError(this.message);
+  String get tip => null;
+  SourceSpan get span => null;
+
+  _StringMessage(this.message);
 
   String toString() => message;
 }

pkg/front_end/lib/src/fasta/fasta_codes_generated.dart

@@ -1432,6 +1432,28 @@ Message _withArgumentsInternalProblemUnsupported(String name) {
       arguments: {'name': name});
 }
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String string)>
+    templateInternalVerificationError =
+    const Template<Message Function(String string)>(
+        messageTemplate:
+            r"""Verification of the generated program failed: #string.""",
+        withArguments: _withArgumentsInternalVerificationError);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string)> codeInternalVerificationError =
+    const Code<Message Function(String string)>(
+  "InternalVerificationError",
+  templateInternalVerificationError,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInternalVerificationError(String string) {
+  return new Message(codeInternalVerificationError,
+      message: """Verification of the generated program failed: $string.""",
+      arguments: {'string': string});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeInvalidAwaitFor = messageInvalidAwaitFor;
 
@@ -1582,6 +1604,35 @@ const MessageCode messageMissingExponent = const MessageCode("MissingExponent",
     tip:
         r"""Make sure there is an exponent, and remove any whitespace before it.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String string)> templateMissingInputFile =
+    const Template<Message Function(String string)>(
+        messageTemplate: r"""Input file not found: #string.""",
+        withArguments: _withArgumentsMissingInputFile);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string)> codeMissingInputFile =
+    const Code<Message Function(String string)>(
+  "MissingInputFile",
+  templateMissingInputFile,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsMissingInputFile(String string) {
+  return new Message(codeMissingInputFile,
+      message: """Input file not found: $string.""",
+      arguments: {'string': string});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Null> codeMissingMain = messageMissingMain;
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const MessageCode messageMissingMain = const MessageCode("MissingMain",
+    dart2jsCode: "MISSING_MAIN",
+    message: r"""No 'main' method found.""",
+    tip: r"""Try adding a method named 'main' to your program.""");
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Template<
     Message Function(Uri uri_)> templateMissingPartOf = const Template<
@@ -1606,6 +1657,46 @@ Message _withArgumentsMissingPartOf(Uri uri_) {
       arguments: {'uri': uri_});
 }
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String string)> templateMissingSdkRoot =
+    const Template<Message Function(String string)>(
+        messageTemplate: r"""SDK root directory not found: #string.""",
+        withArguments: _withArgumentsMissingSdkRoot);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string)> codeMissingSdkRoot =
+    const Code<Message Function(String string)>(
+  "MissingSdkRoot",
+  templateMissingSdkRoot,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsMissingSdkRoot(String string) {
+  return new Message(codeMissingSdkRoot,
+      message: """SDK root directory not found: $string.""",
+      arguments: {'string': string});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String string)> templateMissingSdkSummary =
+    const Template<Message Function(String string)>(
+        messageTemplate: r"""SDK summary not found: #string.""",
+        withArguments: _withArgumentsMissingSdkSummary);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string)> codeMissingSdkSummary =
+    const Code<Message Function(String string)>(
+  "MissingSdkSummary",
+  templateMissingSdkSummary,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsMissingSdkSummary(String string) {
+  return new Message(codeMissingSdkSummary,
+      message: """SDK summary not found: $string.""",
+      arguments: {'string': string});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeNamedFunctionExpression = messageNamedFunctionExpression;
 

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

@@ -643,7 +643,7 @@ class KernelTarget extends TargetImplementation {
 
   void verify() {
     var verifyErrors = verifyProgram(program);
-    errors.addAll(verifyErrors.map((error) => '$error'));
+    errors.addAll(verifyErrors.map((error) => error.message));
     ticker.logMs("Verified program");
   }
 

pkg/front_end/lib/src/fasta/kernel/verifier.dart

@@ -24,13 +24,14 @@ import 'package:kernel/verifier.dart' show VerificationError, VerifyingVisitor;
 
 import '../deprecated_problems.dart' show deprecated_printUnexpected;
 
+import '../fasta_codes.dart';
+
 import 'redirecting_factory_body.dart' show RedirectingFactoryBody;
 
-List<VerificationError> verifyProgram(Program program,
-    {bool isOutline: false}) {
+List<LocatedMessage> verifyProgram(Program program, {bool isOutline: false}) {
   FastaVerifyingVisitor verifier = new FastaVerifyingVisitor(isOutline);
   program.accept(verifier);
-  return verifier.errors;
+  return verifier.errors.map(convertError).toList();
 }
 
 class FastaVerifyingVisitor extends VerifyingVisitor
@@ -106,3 +107,13 @@ class FastaVerifyingVisitor extends VerifyingVisitor
     problem(null, "Unexpected appearance of the unknown type.");
   }
 }
+
+LocatedMessage convertError(VerificationError error) {
+  var node = error.node ?? error.context;
+  int offset = node?.fileOffset ?? -1;
+  var file = node?.location?.file;
+  Uri uri = file == null ? null : Uri.parse(file);
+  return templateInternalVerificationError
+      .withArguments(error.details)
+      .withLocation(uri, offset);
+}

pkg/front_end/lib/src/fasta/problems.dart

@@ -34,7 +34,7 @@ dynamic internalProblem(Message message, int charOffset, Uri uri) {
   }
 }
 
-dynamic unimplemented(String what, int charOffset, Uri uri) {
+dynamic unimplemented(String what, [int charOffset = -1, Uri uri = null]) {
   return internalProblem(
       templateInternalProblemUnimplemented.withArguments(what),
       charOffset,

pkg/front_end/lib/src/kernel_generator_impl.dart

@@ -120,7 +120,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
         trimProgram(summaryProgram, (uri) => !excluded.contains(uri));
       }
       if (options.verify) {
-        verifyProgram(summaryProgram).forEach((e) => options.reportError('$e'));
+        verifyProgram(summaryProgram).forEach(options.reportMessage);
       }
       if (options.debugDump) {
         printProgramText(summaryProgram,
@@ -147,7 +147,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
     }
 
     if (kernelTarget.errors.isNotEmpty) {
-      kernelTarget.errors.forEach(options.reportError);
+      kernelTarget.errors.forEach(options.deprecated_reportError);
       return null;
     }
 
@@ -156,7 +156,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
         program: program,
         deps: kernelTarget.loader.getDependencies());
   } on deprecated_InputError catch (e) {
-    options.reportError(e.deprecated_format());
+    options.deprecated_reportError(e.deprecated_format());
     return null;
   } catch (e, t) {
     return reportCrash(e, t);

pkg/front_end/messages.yaml

@@ -624,6 +624,9 @@ InternalProblemAlreadyInitialized:
 InternalProblemBodyOnAbstractMethod:
   template: "Attempting to set body on abstract method."
 
+InternalVerificationError:
+  template: "Verification of the generated program failed: #string."
+
 LocalDefinitionHidesExport:
   template: "Local definition of '#name' hides export from '#uri'."
 
@@ -781,3 +784,17 @@ PartOfUseUri:
 
 PartOfUriMismatch:
   template: "Using '#uri' as part of '#uri2' but its 'part of' declaration says '#string'."
+
+MissingMain:
+  template: "No 'main' method found."
+  tip: "Try adding a method named 'main' to your program."
+  dart2jsCode: MISSING_MAIN
+
+MissingInputFile:
+  template: "Input file not found: #string."
+
+MissingSdkRoot:
+  template: "SDK root directory not found: #string."
+
+MissingSdkSummary:
+  template: "SDK summary not found: #string."