Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/lib/src/validator/dependency.dart

Index: sdk/lib/_internal/pub_generated/lib/src/validator/dependency.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/validator/dependency.dart b/sdk/lib/_internal/pub_generated/lib/src/validator/dependency.dart
deleted file mode 100644
index 4440ff7b558d4607ce92033f8b774956f87aa33b..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/validator/dependency.dart
+++ /dev/null
@@ -1,275 +0,0 @@
-// 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 pub.validator.dependency;
-
-import 'dart:async';
-
-import 'package:pub_semver/pub_semver.dart';
-
-import '../entrypoint.dart';
-import '../log.dart' as log;
-import '../package.dart';
-import '../utils.dart';
-import '../validator.dart';
-
-/// The range of all pub versions that don't support `^` version constraints.
-///
-/// This is the actual range of pub versions, whereas [_postCaretPubVersions] is
-/// the nicer-looking range that doesn't include a prerelease tag.
-final _preCaretPubVersions = new VersionConstraint.parse("<1.8.0-dev.3.0");
-
-/// The range of all pub versions that do support `^` version constraints.
-///
-/// This is intersected with the user's SDK constraint to provide a suggested
-/// constraint.
-final _postCaretPubVersions = new VersionConstraint.parse("^1.8.0");
-
-/// A validator that validates a package's dependencies.
-class DependencyValidator extends Validator {
-  /// Whether the SDK constraint guarantees that `^` version constraints are
-  /// safe.
-  bool get _caretAllowed =>
-      entrypoint.root.pubspec.environment.sdkVersion.intersect(
-          _preCaretPubVersions).isEmpty;
-
-  DependencyValidator(Entrypoint entrypoint)
-      : super(entrypoint);
-
-  Future validate() {
-    final completer0 = new Completer();
-    scheduleMicrotask(() {
-      try {
-        var caretDeps = [];
-        var it0 = entrypoint.root.pubspec.dependencies.iterator;
-        break0() {
-          join0() {
-            completer0.complete();
-          }
-          if (caretDeps.isNotEmpty && !_caretAllowed) {
-            _errorAboutCaretConstraints(caretDeps);
-            join0();
-          } else {
-            join0();
-          }
-        }
-        var trampoline0;
-        continue0() {
-          trampoline0 = null;
-          if (it0.moveNext()) {
-            var dependency = it0.current;
-            join1() {
-              trampoline0 = continue0;
-              do trampoline0(); while (trampoline0 != null);
-            }
-            if (dependency.source != "hosted") {
-              new Future.value(_warnAboutSource(dependency)).then((x0) {
-                trampoline0 = () {
-                  trampoline0 = null;
-                  try {
-                    x0;
-                    join1();
-                  } catch (e0, s0) {
-                    completer0.completeError(e0, s0);
-                  }
-                };
-                do trampoline0(); while (trampoline0 != null);
-              }, onError: completer0.completeError);
-            } else {
-              join2() {
-                join1();
-              }
-              if (dependency.constraint.isAny) {
-                _warnAboutNoConstraint(dependency);
-                join2();
-              } else {
-                join3() {
-                  join2();
-                }
-                if (dependency.constraint is Version) {
-                  _warnAboutSingleVersionConstraint(dependency);
-                  join3();
-                } else {
-                  join4() {
-                    join3();
-                  }
-                  if (dependency.constraint is VersionRange) {
-                    join5() {
-                      join6() {
-                        join4();
-                      }
-                      if (dependency.constraint.toString().startsWith("^")) {
-                        caretDeps.add(dependency);
-                        join6();
-                      } else {
-                        join6();
-                      }
-                    }
-                    if (dependency.constraint.min == null) {
-                      _warnAboutNoConstraintLowerBound(dependency);
-                      join5();
-                    } else {
-                      join7() {
-                        join5();
-                      }
-                      if (dependency.constraint.max == null) {
-                        _warnAboutNoConstraintUpperBound(dependency);
-                        join7();
-                      } else {
-                        join7();
-                      }
-                    }
-                  } else {
-                    join4();
-                  }
-                }
-              }
-            }
-          } else {
-            break0();
-          }
-        }
-        trampoline0 = continue0;
-        do trampoline0(); while (trampoline0 != null);
-      } catch (e, s) {
-        completer0.completeError(e, s);
-      }
-    });
-    return completer0.future;
-  }
-
-  /// Warn that dependencies should use the hosted source.
-  Future _warnAboutSource(PackageDep dep) {
-    return entrypoint.cache.sources['hosted'].getVersions(
-        dep.name,
-        dep.name).catchError((e) => <Version>[]).then((versions) {
-      var constraint;
-      var primary = Version.primary(versions);
-      if (primary != null) {
-        constraint = _constraintForVersion(primary);
-      } else {
-        constraint = dep.constraint.toString();
-        if (!dep.constraint.isAny && dep.constraint is! Version) {
-          constraint = '"$constraint"';
-        }
-      }
-
-      // Path sources are errors. Other sources are just warnings.
-      var messages = warnings;
-      if (dep.source == "path") {
-        messages = errors;
-      }
-
-      messages.add(
-          'Don\'t depend on "${dep.name}" from the ${dep.source} '
-              'source. Use the hosted source instead. For example:\n' '\n' 'dependencies:\n'
-              '  ${dep.name}: $constraint\n' '\n'
-              'Using the hosted source ensures that everyone can download your '
-              'package\'s dependencies along with your package.');
-    });
-  }
-
-  /// Warn that dependencies should have version constraints.
-  void _warnAboutNoConstraint(PackageDep dep) {
-    var message =
-        'Your dependency on "${dep.name}" should have a version ' 'constraint.';
-    var locked = entrypoint.lockFile.packages[dep.name];
-    if (locked != null) {
-      message =
-          '$message For example:\n' '\n' 'dependencies:\n'
-              '  ${dep.name}: ${_constraintForVersion(locked.version)}\n';
-    }
-    warnings.add(
-        "$message\n"
-            'Without a constraint, you\'re promising to support ${log.bold("all")} '
-            'future versions of "${dep.name}".');
-  }
-
-  /// Warn that dependencies should allow more than a single version.
-  void _warnAboutSingleVersionConstraint(PackageDep dep) {
-    warnings.add(
-        'Your dependency on "${dep.name}" should allow more than one version. '
-            'For example:\n' '\n' 'dependencies:\n'
-            '  ${dep.name}: ${_constraintForVersion(dep.constraint)}\n' '\n'
-            'Constraints that are too tight will make it difficult for people to '
-            'use your package\n'
-            'along with other packages that also depend on "${dep.name}".');
-  }
-
-  /// Warn that dependencies should have lower bounds on their constraints.
-  void _warnAboutNoConstraintLowerBound(PackageDep dep) {
-    var message = 'Your dependency on "${dep.name}" should have a lower bound.';
-    var locked = entrypoint.lockFile.packages[dep.name];
-    if (locked != null) {
-      var constraint;
-      if (locked.version == (dep.constraint as VersionRange).max) {
-        constraint = _constraintForVersion(locked.version);
-      } else {
-        constraint = '">=${locked.version} ${dep.constraint}"';
-      }
-
-      message =
-          '$message For example:\n' '\n' 'dependencies:\n' '  ${dep.name}: $constraint\n';
-    }
-    warnings.add(
-        "$message\n"
-            'Without a constraint, you\'re promising to support ${log.bold("all")} '
-            'previous versions of "${dep.name}".');
-  }
-
-  /// Warn that dependencies should have upper bounds on their constraints.
-  void _warnAboutNoConstraintUpperBound(PackageDep dep) {
-    var constraint;
-    if ((dep.constraint as VersionRange).includeMin) {
-      constraint = _constraintForVersion((dep.constraint as VersionRange).min);
-    } else {
-      constraint =
-          '"${dep.constraint} ' '<${(dep.constraint as VersionRange).min.nextBreaking}"';
-    }
-
-    warnings.add(
-        'Your dependency on "${dep.name}" should have an upper bound. For ' 'example:\n'
-            '\n' 'dependencies:\n' '  ${dep.name}: $constraint\n' '\n'
-            'Without an upper bound, you\'re promising to support '
-            '${log.bold("all")} future versions of ${dep.name}.');
-  }
-
-  /// Emits an error for any version constraints that use `^` without an
-  /// appropriate SDK constraint.
-  void _errorAboutCaretConstraints(List<PackageDep> caretDeps) {
-    var newSdkConstraint =
-        entrypoint.root.pubspec.environment.sdkVersion.intersect(_postCaretPubVersions);
-
-    if (newSdkConstraint.isEmpty) newSdkConstraint = _postCaretPubVersions;
-
-    var buffer = new StringBuffer(
-        "Older versions of pub don't support ^ version constraints.\n"
-            "Make sure your SDK constraint excludes those old versions:\n" "\n"
-            "environment:\n" "  sdk: \"$newSdkConstraint\"\n" "\n");
-
-    if (caretDeps.length == 1) {
-      buffer.writeln("Or use a fully-expanded constraint:");
-    } else {
-      buffer.writeln("Or use fully-expanded constraints:");
-    }
-
-    buffer.writeln();
-    buffer.writeln("dependencies:");
-
-    caretDeps.forEach((dep) {
-      VersionRange constraint = dep.constraint;
-      buffer.writeln(
-          "  ${dep.name}: \">=${constraint.min} <${constraint.max}\"");
-    });
-
-    errors.add(buffer.toString().trim());
-  }
-
-  /// Returns the suggested version constraint for a dependency that was tested
-  /// against [version].
-  String _constraintForVersion(Version version) {
-    if (_caretAllowed) return "^$version";
-    return '">=$version <${version.nextBreaking}"';
-  }
-}