Infer package URIs

Closes #33076

Change-Id: I73db84eadaf3ba723c2f1323f9b883077a4df9df
Reviewed-on: https://dart-review.googlesource.com/c/78246
Commit-Queue: Peter von der Ahé <[email protected]>
Reviewed-by: Jens Johansen <[email protected]>

Author: peter-ahe-google

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

@@ -59,8 +59,6 @@ import '../fasta/ticker.dart' show Ticker;
 
 import '../fasta/uri_translator.dart' show UriTranslator;
 
-import '../fasta/uri_translator_impl.dart' show UriTranslatorImpl;
-
 import 'libraries_specification.dart'
     show
         LibrariesSpecification,
@@ -95,7 +93,7 @@ class ProcessedOptions {
 
   /// The object that knows how to resolve "package:" and "dart:" URIs,
   /// or `null` if it has not been computed yet.
-  UriTranslatorImpl _uriTranslator;
+  UriTranslator _uriTranslator;
 
   /// The SDK summary, or `null` if it has not been read yet.
   ///
@@ -382,7 +380,7 @@ class ProcessedOptions {
   ///
   /// This is an asynchronous method since file system operations may be
   /// required to locate/read the packages file as well as SDK metadata.
-  Future<UriTranslatorImpl> getUriTranslator({bool bypassCache: false}) async {
+  Future<UriTranslator> getUriTranslator({bool bypassCache: false}) async {
     if (bypassCache) {
       _uriTranslator = null;
       _packages = null;
@@ -393,7 +391,7 @@ class ProcessedOptions {
       ticker.logMs("Read libraries file");
       var packages = await _getPackages();
       ticker.logMs("Read packages file");
-      _uriTranslator = new UriTranslatorImpl(libraries, packages);
+      _uriTranslator = new UriTranslator(libraries, packages);
     }
     return _uriTranslator;
   }

pkg/front_end/lib/src/fasta/dill/dill_target.dart

@@ -37,11 +37,6 @@ class DillTarget extends TargetImplementation {
     unsupported("addSourceInformation", -1, null);
   }
 
-  @override
-  void read(Uri uri) {
-    unsupported("read", -1, null);
-  }
-
   @override
   Future<Null> buildComponent() {
     return new Future<Null>.sync(() => unsupported("buildComponent", -1, null));

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

@@ -4294,6 +4294,26 @@ const MessageCode messageIncorrectTypeArgumentVariable = const MessageCode(
     severity: Severity.context,
     message: r"""Bound of this variable is violated.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(Uri uri_)> templateInferredPackageUri =
+    const Template<Message Function(Uri uri_)>(
+        messageTemplate: r"""Interpreting this as package URI, '#uri'.""",
+        withArguments: _withArgumentsInferredPackageUri);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(Uri uri_)> codeInferredPackageUri =
+    const Code<Message Function(Uri uri_)>(
+        "InferredPackageUri", templateInferredPackageUri,
+        severity: Severity.warning);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInferredPackageUri(Uri uri_) {
+  String uri = relativizeUri(uri_);
+  return new Message(codeInferredPackageUri,
+      message: """Interpreting this as package URI, '${uri}'.""",
+      arguments: {'uri': uri_});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeInheritedMembersConflict = messageInheritedMembersConflict;
 

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

@@ -53,7 +53,7 @@ Future<List<Uri>> getDependencies(Uri script,
         fileSystem, false, dillTarget, uriTranslator,
         uriToSource: c.uriToSource);
 
-    kernelTarget.read(script);
+    kernelTarget.setEntryPoints(<Uri>[script]);
     await dillTarget.buildOutlines();
     await kernelTarget.loader.buildOutlines();
     return new List<Uri>.from(c.dependencies);

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

@@ -251,7 +251,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
 
       Component componentWithDill;
       try {
-        userCode.read(entryPoint);
+        userCode.setEntryPoints(<Uri>[entryPoint]);
         await userCode.buildOutlines();
 
         // This is not the full component. It is the component including all

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

@@ -63,6 +63,7 @@ import '../messages.dart'
         noLength,
         templateFinalFieldNotInitialized,
         templateFinalFieldNotInitializedByConstructor,
+        templateInferredPackageUri,
         templateMissingImplementationCause,
         templateSuperclassHasNoDefaultConstructor;
 
@@ -152,8 +153,40 @@ class KernelTarget extends TargetImplementation {
     uriToSource[uri] = new Source(lineStarts, sourceCode);
   }
 
-  void read(Uri uri) {
-    loader.read(uri, -1, accessor: loader.first);
+  void setEntryPoints(List<Uri> entryPoints) {
+    Map<String, Uri> packagesMap;
+    for (Uri entryPoint in entryPoints) {
+      String scheme = entryPoint.scheme;
+      Uri fileUri;
+      switch (scheme) {
+        case "package":
+        case "dart":
+        case "data":
+          break;
+        default:
+          // Attempt to reverse-lookup [entryPoint] in package config.
+          String asString = "$entryPoint";
+          packagesMap ??= uriTranslator.packages.asMap();
+          for (String packageName in packagesMap.keys) {
+            String prefix = "${packagesMap[packageName]}";
+            if (asString.startsWith(prefix)) {
+              Uri reversed = Uri.parse(
+                  "package:$packageName/${asString.substring(prefix.length)}");
+              if (entryPoint == uriTranslator.translate(reversed)) {
+                loader.addProblem(
+                    templateInferredPackageUri.withArguments(reversed),
+                    -1,
+                    1,
+                    entryPoint);
+                fileUri = entryPoint;
+                entryPoint = reversed;
+                break;
+              }
+            }
+          }
+      }
+      loader.read(entryPoint, -1, accessor: loader.first, fileUri: fileUri);
+    }
   }
 
   @override

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

@@ -44,7 +44,6 @@ Severity rewriteSeverity(
     switch (path.substring(fastaPath.length + index)) {
       case "command_line.dart":
       case "deprecated_problems.dart":
-      case "entry_points.dart":
       case "kernel/body_builder.dart":
       case "source/diet_listener.dart":
         return severity;

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

@@ -20,9 +20,6 @@ abstract class Target {
 
   Target(this.ticker);
 
-  /// Instructs this target to include [uri] in its result.
-  void read(Uri uri);
-
   /// Build and return outlines for all libraries.
   Future<Component> buildOutlines();
 

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

@@ -4,29 +4,81 @@
 
 library fasta.uri_translator;
 
-/// Instances of [UriTranslator] translate absolute URIs into corresponding
-/// file URIs in a [FileSystem]. Translated URIs are typically `file:` URIs,
-/// but may use a different scheme depending on the used custom file system.
-abstract class UriTranslator {
-  /// Return the URIs of patches that should be applied to the platform library
-  /// with the given [libraryName], or `null` if there are no patches to apply.
-  List<Uri> getDartPatches(String libraryName);
-
-  /// Returns `true` if [uri] is private to the platform libraries (and thus
-  /// not accessible from user code).
-  bool isPlatformImplementation(Uri uri);
-
-  /// Return the corresponding file URI for the given absolute [uri], or `null`
-  /// if there is no corresponding file URI, or the given [uri] is already a
-  /// file URI.
-  ///
-  /// Note: this only translates the URI, there is no guarantee that the
-  /// corresponding file exists in the file system.
-  ///
-  /// If [reportMessage] is true a message will be reported via
-  /// [CompilerContext.current].
-  Uri translate(Uri uri, [bool reportMessage = true]);
-
-  /// Whether the given [libraryName] is supported by the underlying target.
-  bool isLibrarySupported(String libraryName);
+import 'package:package_config/packages.dart' show Packages;
+
+import '../base/libraries_specification.dart' show TargetLibrariesSpecification;
+import 'compiler_context.dart' show CompilerContext;
+import 'fasta_codes.dart';
+import 'severity.dart' show Severity;
+
+class UriTranslator {
+  final TargetLibrariesSpecification dartLibraries;
+
+  final Packages packages;
+
+  UriTranslator(this.dartLibraries, this.packages);
+
+  List<Uri> getDartPatches(String libraryName) =>
+      dartLibraries.libraryInfoFor(libraryName)?.patches;
+
+  bool isPlatformImplementation(Uri uri) {
+    if (uri.scheme != "dart") return false;
+    String path = uri.path;
+    return dartLibraries.libraryInfoFor(path) == null || path.startsWith("_");
+  }
+
+  // TODO(sigmund, ahe): consider expanding this API to include an error
+  // callback, so we can provide an error location when one is available. For
+  // example, if the error occurs in an `import`.
+  Uri translate(Uri uri, [bool reportMessage = true]) {
+    if (uri.scheme == "dart") return _translateDartUri(uri);
+    if (uri.scheme == "package") {
+      return _translatePackageUri(uri, reportMessage);
+    }
+    return null;
+  }
+
+  bool isLibrarySupported(String libraryName) {
+    // TODO(sigmund): change this to `?? false` when all backends provide the
+    // `libraries.json` file by default (Issue #32657).
+    return dartLibraries.libraryInfoFor(libraryName)?.isSupported ?? true;
+  }
+
+  Uri _translateDartUri(Uri uri) {
+    if (!uri.isScheme('dart')) return null;
+    return dartLibraries.libraryInfoFor(uri.path)?.uri;
+  }
+
+  Uri _translatePackageUri(Uri uri, bool reportMessage) {
+    try {
+      // TODO(sigmund): once we remove the `parse` API, we can ensure that
+      // packages will never be null and get rid of `?` below.
+      return packages?.resolve(uri,
+          notFound: reportMessage
+              ? _packageUriNotFound
+              : _packageUriNotFoundNoReport);
+    } on ArgumentError catch (e) {
+      // TODO(sigmund): catch a more precise error when
+      // https://github.com/dart-lang/package_config/issues/40 is fixed.
+      if (reportMessage) {
+        CompilerContext.current.reportWithoutLocation(
+            templateInvalidPackageUri.withArguments(uri, '$e'), Severity.error);
+      }
+      return null;
+    }
+  }
+
+  static Uri _packageUriNotFound(Uri uri) {
+    String name = uri.pathSegments.first;
+    CompilerContext.current.reportWithoutLocation(
+        templatePackageNotFound.withArguments(name, uri), Severity.error);
+    // TODO(sigmund, ahe): ensure we only report an error once,
+    // this null result will likely cause another error further down in the
+    // compiler.
+    return null;
+  }
+
+  static Uri _packageUriNotFoundNoReport(Uri uri) {
+    return null;
+  }
 }

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

@@ -106,7 +106,7 @@ Future<CompilerResult> generateKernelInternal(
         var kernelTarget =
             new KernelTarget(fs, false, dillTarget, uriTranslator);
         sourceLoader = kernelTarget.loader;
-        options.inputs.forEach(kernelTarget.read);
+        kernelTarget.setEntryPoints(options.inputs);
         Component summaryComponent =
             await kernelTarget.buildOutlines(nameRoot: nameRoot);
         List<int> summary = null;

pkg/front_end/lib/src/kernel_generator_impl.dart

@@ -3213,3 +3213,13 @@ IncorrectTypeArgumentInSupertypeInferred:
 IncorrectTypeArgumentVariable:
   template: "Bound of this variable is violated."
   severity: CONTEXT
+
+InferredPackageUri:
+  template: "Interpreting this as package URI, '#uri'."
+  severity: WARNING
+  frontendInternal: true
+  script:
+    "main.dart": |
+      main() {}
+    ".packages": |
+      example:./