Remove the limited invalidation feature.

pkg/analyzer/lib/src/task/dart.dart

Index: pkg/analyzer/lib/src/task/dart.dart
diff --git a/pkg/analyzer/lib/src/task/dart.dart b/pkg/analyzer/lib/src/task/dart.dart
index a7856f9490311fdd1e8cd44ca8cd74738d1130f0..6c999e4501dfe5748e0faf1dd01ed3ebf79c6a31 100644
--- a/pkg/analyzer/lib/src/task/dart.dart
+++ b/pkg/analyzer/lib/src/task/dart.dart
@@ -43,7 +43,6 @@ import 'package:analyzer/src/services/lint.dart';
 import 'package:analyzer/src/task/driver.dart';
 import 'package:analyzer/src/task/general.dart';
 import 'package:analyzer/src/task/html.dart';
-import 'package:analyzer/src/task/incremental_element_builder.dart';
 import 'package:analyzer/src/task/inputs.dart';
 import 'package:analyzer/src/task/model.dart';
 import 'package:analyzer/src/task/strong/checker.dart';
@@ -2466,338 +2465,6 @@ class ContainingLibrariesTask extends SourceBasedAnalysisTask {
 }
 
 /**
- * The description for a change in a Dart source.
- */
-class DartDelta extends Delta {
-  final Set<String> changedNames = new Set<String>();
-  final Map<Source, Set<String>> changedPrivateNames = <Source, Set<String>>{};
-
-  final Map<String, ClassElementDelta> changedClasses =
-      <String, ClassElementDelta>{};
-
-  /**
-   * The cache of libraries in which all results are invalid.
-   */
-  final Set<Source> librariesWithAllInvalidResults = new Set<Source>();
-
-  /**
-   * The cache of libraries in which all results are valid.
-   */
-  final Set<Source> librariesWithAllValidResults = new Set<Source>();
-
-  /**
-   * The cache of libraries with all, but [HINTS] and [VERIFY_ERRORS] results
-   * are valid.
-   */
-  final Set<Source> libraryWithInvalidErrors = new Set<Source>();
-
-  /**
-   * This set is cleared in every [gatherEnd], and [gatherChanges] uses it
-   * to find changes in every source only once per visit process.
-   */
-  final Set<Source> currentVisitUnits = new Set<Source>();
-
-  DartDelta(Source source) : super(source);
-
-  @override
-  bool get shouldGatherChanges => true;
-
-  /**
-   * Add names that are changed in the given [references].
-   * Return `true` if any change was added.
-   */
-  bool addChangedElements(ReferencedNames references, Source refLibrary) {
-    int numberOfChanges = 0;
-    int lastNumberOfChange = -1;
-    while (numberOfChanges != lastNumberOfChange) {
-      lastNumberOfChange = numberOfChanges;
-      // Classes that extend changed classes are also changed.
-      // If there is a delta for a superclass, use it for the subclass.
-      // Otherwise mark the subclass as "general name change".
-      references.superToSubs.forEach((String superName, Set<String> subNames) {
-        ClassElementDelta superDelta = changedClasses[superName];
-        for (String subName in subNames) {
-          if (superDelta != null) {
-            ClassElementDelta subDelta = changedClasses.putIfAbsent(subName,
-                () => new ClassElementDelta(null, refLibrary, subName));
-            _log(() => '$subName in $refLibrary has delta because of its '
-                'superclass $superName has delta');
-            if (subDelta.superDeltas.add(superDelta)) {
-              numberOfChanges++;
-            }
-          } else if (isChanged(refLibrary, superName)) {
-            if (nameChanged(refLibrary, subName)) {
-              _log(() => '$subName in $refLibrary is changed because its '
-                  'superclass $superName is changed');
-              numberOfChanges++;
-            }
-          }
-        }
-      });
-      // If a user element uses a changed top-level element, then the user is
-      // also changed. Note that if a changed class with delta is used, this
-      // does not make the user changed - classes with delta keep their
-      // original elements, so resolution of their names does not change.
-      references.userToDependsOn.forEach((user, dependencies) {
-        for (String dependency in dependencies) {
-          if (isChangedOrClassMember(refLibrary, dependency)) {
-            if (nameChanged(refLibrary, user)) {
-              _log(() => '$user in $refLibrary is changed because '
-                  'of $dependency in $dependencies');
-              numberOfChanges++;
-            }
-          }
-        }
-      });
-    }
-    return numberOfChanges != 0;
-  }
-
-  void classChanged(ClassElementDelta classDelta) {
-    changedClasses[classDelta.name] = classDelta;
-  }
-
-  void elementChanged(Element element) {
-    Source librarySource = element.library.source;
-    nameChanged(librarySource, element.name);
-  }
-
-  @override
-  bool gatherChanges(InternalAnalysisContext context, AnalysisTarget target,
-      ResultDescriptor descriptor, Object value) {
-    // Prepare target source.
-    Source targetUnit = target.source;
-    Source targetLibrary = target.librarySource;
-    if (target is Source) {
-      if (context.getKindOf(target) == SourceKind.LIBRARY) {
-        targetLibrary = target;
-      }
-    }
-    // We don't know what to do with the given target.
-    if (targetUnit == null || targetUnit != targetLibrary) {
-      return false;
-    }
-    // Attempt to find new changed names for the unit only once.
-    if (!currentVisitUnits.add(targetUnit)) {
-      return false;
-    }
-    // Add changes.
-    ReferencedNames referencedNames =
-        context.getResult(targetUnit, REFERENCED_NAMES);
-    if (referencedNames == null) {
-      return false;
-    }
-    return addChangedElements(referencedNames, targetLibrary);
-  }
-
-  @override
-  void gatherEnd() {
-    currentVisitUnits.clear();
-  }
-
-  bool hasAffectedHintsVerifyErrors(
-      ReferencedNames references, Source refLibrary) {
-    for (String superName in references.superToSubs.keys) {
-      if (isChangedOrClass(refLibrary, superName)) {
-        _log(() => '$refLibrary hints/verify errors are affected because '
-            '${references.superToSubs[superName]} subclasses $superName');
-        return true;
-      }
-    }
-    for (String name in references.names) {
-      ClassElementDelta classDelta = changedClasses[name];
-      if (classDelta != null && classDelta.hasAnnotationChanges) {
-        _log(() => '$refLibrary hints/verify errors are  affected because '
-            '$name has a class delta with annotation changes');
-        return true;
-      }
-    }
-    return false;
-  }
-
-  bool hasAffectedReferences(ReferencedNames references, Source refLibrary) {
-    // Resolution must be performed when a referenced element changes.
-    for (String name in references.names) {
-      if (isChangedOrClassMember(refLibrary, name)) {
-        _log(() => '$refLibrary is affected by $name');
-        return true;
-      }
-    }
-    // Resolution must be performed when the unnamed constructor of
-    // an instantiated class is added/changed/removed.
-    // TODO(scheglov) Use only instantiations with default constructor.
-    for (String name in references.instantiatedNames) {
-      for (ClassElementDelta classDelta in changedClasses.values) {
-        if (classDelta.name == name && classDelta.hasUnnamedConstructorChange) {
-          _log(() =>
-              '$refLibrary is affected by the default constructor of $name');
-          return true;
-        }
-      }
-    }
-    for (String name in references.extendedUsedUnnamedConstructorNames) {
-      for (ClassElementDelta classDelta in changedClasses.values) {
-        if (classDelta.name == name && classDelta.hasUnnamedConstructorChange) {
-          _log(() =>
-              '$refLibrary is affected by the default constructor of $name');
-          return true;
-        }
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Return `true` if the given [name], used in a unit of the [librarySource],
-   * is affected by a changed top-level element, excluding classes.
-   */
-  bool isChanged(Source librarySource, String name) {
-    if (_isPrivateName(name)) {
-      if (changedPrivateNames[librarySource]?.contains(name) ?? false) {
-        return true;
-      }
-    }
-    return changedNames.contains(name);
-  }
-
-  /**
-   * Return `true` if the given [name], used in a unit of the [librarySource],
-   * is affected by a changed top-level element or a class.
-   */
-  bool isChangedOrClass(Source librarySource, String name) {
-    if (isChanged(librarySource, name)) {
-      return true;
-    }
-    return changedClasses[name] != null;
-  }
-
-  /**
-   * Return `true` if the given [name], used in a unit of the [librarySource],
-   * is affected by a changed top-level element or a class member.
-   */
-  bool isChangedOrClassMember(Source librarySource, String name) {
-    if (isChanged(librarySource, name)) {
-      return true;
-    }
-    // TODO(scheglov) Optimize this.
-    for (ClassElementDelta classDelta in changedClasses.values) {
-      if (classDelta.hasChanges(librarySource, name)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Register the fact that the given [name], defined in the [librarySource]
-   * is changed.  Return `true` if the [name] is a new name, not yet registered.
-   */
-  bool nameChanged(Source librarySource, String name) {
-    if (_isPrivateName(name)) {
-      return changedPrivateNames
-          .putIfAbsent(librarySource, () => new Set<String>())
-          .add(name);
-    } else {
-      return changedNames.add(name);
-    }
-  }
-
-  @override
-  DeltaResult validate(InternalAnalysisContext context, AnalysisTarget target,
-      ResultDescriptor descriptor, Object value) {
-    // Always invalidate compounding results.
-    if (descriptor == LIBRARY_ELEMENT4 ||
-        descriptor == READY_LIBRARY_ELEMENT6 ||
-        descriptor == READY_LIBRARY_ELEMENT7) {
-      return DeltaResult.INVALIDATE_KEEP_DEPENDENCIES;
-    }
-    // Prepare target source.
-    Source targetUnit = target.source;
-    Source targetLibrary = target.librarySource;
-    if (target is Source) {
-      if (context.getKindOf(target) == SourceKind.LIBRARY) {
-        targetLibrary = target;
-      }
-    }
-    // We don't know what to do with the given target, invalidate it.
-    if (targetUnit == null || targetUnit != targetLibrary) {
-      return DeltaResult.INVALIDATE;
-    }
-    // Keep results that don't change: any library.
-    if (_isTaskResult(ScanDartTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(ParseDartTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(BuildCompilationUnitElementTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(BuildLibraryElementTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(BuildDirectiveElementsTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(ResolveDirectiveElementsTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(BuildEnumMemberElementsTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(BuildSourceExportClosureTask.DESCRIPTOR, descriptor) ||
-        _isTaskResult(ReadyLibraryElement2Task.DESCRIPTOR, descriptor) ||
-        _isTaskResult(ComputeLibraryCycleTask.DESCRIPTOR, descriptor)) {
-      return DeltaResult.KEEP_CONTINUE;
-    }
-    // Keep results that don't change: changed library.
-    if (targetUnit == source) {
-      return DeltaResult.INVALIDATE;
-    }
-    // Keep results that don't change: dependent library.
-    if (targetUnit != source) {
-      if (_isTaskResult(BuildPublicNamespaceTask.DESCRIPTOR, descriptor)) {
-        return DeltaResult.KEEP_CONTINUE;
-      }
-    }
-    // Handle in-library results only for now.
-    if (targetLibrary != null) {
-      // Use cached library results.
-      if (librariesWithAllInvalidResults.contains(targetLibrary)) {
-        return DeltaResult.INVALIDATE;
-      }
-      if (librariesWithAllValidResults.contains(targetLibrary)) {
-        return DeltaResult.KEEP_CONTINUE;
-      }
-      // The library is almost, but not completely valid.
-      // Some error results are invalid.
-      if (libraryWithInvalidErrors.contains(targetLibrary)) {
-        if (descriptor == HINTS || descriptor == VERIFY_ERRORS) {
-          return DeltaResult.INVALIDATE_NO_DELTA;
-        }
-        return DeltaResult.KEEP_CONTINUE;
-      }
-      // Compute the library result.
-      ReferencedNames referencedNames =
-          context.getResult(targetUnit, REFERENCED_NAMES);
-      if (referencedNames == null) {
-        return DeltaResult.INVALIDATE_NO_DELTA;
-      }
-      if (hasAffectedReferences(referencedNames, targetLibrary)) {
-        librariesWithAllInvalidResults.add(targetLibrary);
-        return DeltaResult.INVALIDATE;
-      }
-      if (hasAffectedHintsVerifyErrors(referencedNames, targetLibrary)) {
-        libraryWithInvalidErrors.add(targetLibrary);
-        return DeltaResult.KEEP_CONTINUE;
-      }
-      librariesWithAllValidResults.add(targetLibrary);
-      return DeltaResult.KEEP_CONTINUE;
-    }
-    // We don't know what to do with the given target, invalidate it.
-    return DeltaResult.INVALIDATE;
-  }
-
-  void _log(String getMessage()) {
-//    String message = getMessage();
-//    print(message);
-  }
-
-  static bool _isPrivateName(String name) => name.startsWith('_');
-
-  static bool _isTaskResult(
-      TaskDescriptor taskDescriptor, ResultDescriptor result) {
-    return taskDescriptor.results.contains(result);
-  }
-}
-
-/**
  * A task that merges all of the errors for a single source into a single list
  * of errors.
  */