Support optional package name arguments to --show-package-warnings

pkg/compiler/lib/src/apiimpl.dart

 // Copyright (c) 2012, 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.
 
 library leg_apiimpl;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:package_config/packages.dart';
@@ skipping 106 matching lines @@
               hasOption(options, Flags.useContentSecurityPolicy),
             useStartupEmitter: hasOption(options, Flags.fastStartup),
             hasIncrementalSupport:
                 forceIncrementalSupport ||
                 hasOption(options, Flags.incrementalSupport),
             diagnosticOptions: new DiagnosticOptions(
                 suppressWarnings: hasOption(options, Flags.suppressWarnings),
                 fatalWarnings: hasOption(options, Flags.fatalWarnings),
                 suppressHints: hasOption(options, Flags.suppressHints),
                 terseDiagnostics: hasOption(options, Flags.terse),
-                showPackageWarnings:
-                    hasOption(options, Flags.showPackageWarnings)),
+                shownPackageWarnings: extractOptionalCsvOption(
+                      options, Flags.showPackageWarnings)),
             enableExperimentalMirrors:
                 hasOption(options, Flags.enableExperimentalMirrors),
             enableAssertMessage:
                 hasOption(options, Flags.enableAssertMessage),
             generateCodeWithCompileTimeErrors:
                 hasOption(options, Flags.generateCodeWithCompileTimeErrors),
             testMode: hasOption(options, Flags.testMode),
             allowNativeExtensions:
                 hasOption(options, Flags.allowNativeExtensions)) {
     tasks.addAll([
@@ skipping 43 matching lines @@
   // CSV: Comma separated values.
   static List<String> extractCsvOption(List<String> options, String prefix) {
     for (String option in options) {
       if (option.startsWith(prefix)) {
         return option.substring(prefix.length).split(',');
       }
     }
     return const <String>[];
   }
 
+  /// Extract list of comma separated values provided for [flag]. Returns an
+  /// empty list if [option] contain [flag] without arguments. Returns `null` if
+  /// [option] doesn't contain [flag] with or without arguments.
+  static List<String> extractOptionalCsvOption(
+      List<String> options, String flag) {
+    String prefix = '$flag=';
+    for (String option in options) {
+      if (option == flag) {
+        return const <String>[];
+      }
+      if (option.startsWith(flag)) {
+        return option.substring(prefix.length).split(',');
+      }
+    }
+    return null;
+  }
+
   static Uri resolvePlatformConfig(Uri libraryRoot,
                                    List<String> options) {
     String platformConfigPath =
         extractStringOption(options, "--platform-config=", null);
     if (platformConfigPath != null) {
       return libraryRoot.resolve(platformConfigPath);
     } else if (hasOption(options, '--output-type=dart')) {
       return libraryRoot.resolve(_dart2dartPlatform);
     } else {
       Iterable<String> categories = extractCsvOption(options, '--categories=');
@@ skipping 361 matching lines @@
   Uri lookupLibraryUri(String libraryName) {
     assert(invariant(NO_LOCATION_SPANNABLE,
         sdkLibraries != null, message: "setupSdk() has not been run"));
     return sdkLibraries[libraryName];
   }
 
   Uri resolvePatchUri(String libraryName) {
     return backend.resolvePatchUri(libraryName, platformConfigUri);
   }
 }