// Copyright 2018 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.devtools.build.lib.analysis.util;

import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.ImmutableMap.toImmutableMap;
import static com.google.common.collect.Streams.stream;

import com.google.common.base.Functions;
import com.google.common.base.Preconditions;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableListMultimap;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.MapDifference;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.collect.Sets;
import com.google.common.eventbus.EventBus;
import com.google.devtools.build.lib.actions.ActionLookupKey;
import com.google.devtools.build.lib.actions.ArtifactFactory;
import com.google.devtools.build.lib.actions.BuildFailedException;
import com.google.devtools.build.lib.actions.PackageRoots;
import com.google.devtools.build.lib.actions.TestExecException;
import com.google.devtools.build.lib.analysis.AnalysisEnvironment;
import com.google.devtools.build.lib.analysis.AnalysisOptions;
import com.google.devtools.build.lib.analysis.AnalysisResult;
import com.google.devtools.build.lib.analysis.AnalysisUtils;
import com.google.devtools.build.lib.analysis.AspectValue;
import com.google.devtools.build.lib.analysis.BlazeDirectories;
import com.google.devtools.build.lib.analysis.BuildView;
import com.google.devtools.build.lib.analysis.CachingAnalysisEnvironment;
import com.google.devtools.build.lib.analysis.ConfiguredAspect;
import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.ConfiguredTargetFactory;
import com.google.devtools.build.lib.analysis.ConfiguredTargetValue;
import com.google.devtools.build.lib.analysis.DependencyKey;
import com.google.devtools.build.lib.analysis.DependencyKind;
import com.google.devtools.build.lib.analysis.DependencyResolver;
import com.google.devtools.build.lib.analysis.DuplicateException;
import com.google.devtools.build.lib.analysis.ExecGroupCollection;
import com.google.devtools.build.lib.analysis.ExecGroupCollection.InvalidExecGroupException;
import com.google.devtools.build.lib.analysis.InconsistentAspectOrderException;
import com.google.devtools.build.lib.analysis.ResolvedToolchainContext;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.TargetAndConfiguration;
import com.google.devtools.build.lib.analysis.ToolchainCollection;
import com.google.devtools.build.lib.analysis.ToolchainContext;
import com.google.devtools.build.lib.analysis.TopLevelArtifactContext;
import com.google.devtools.build.lib.analysis.ViewCreationFailedException;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationCollection;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
import com.google.devtools.build.lib.analysis.config.BuildOptions;
import com.google.devtools.build.lib.analysis.config.ConfigConditions;
import com.google.devtools.build.lib.analysis.config.ConfigMatchingProvider;
import com.google.devtools.build.lib.analysis.config.ConfigurationResolver;
import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
import com.google.devtools.build.lib.analysis.config.TransitionResolver;
import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
import com.google.devtools.build.lib.analysis.config.transitions.NoTransition;
import com.google.devtools.build.lib.analysis.configuredtargets.MergedConfiguredTarget;
import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
import com.google.devtools.build.lib.analysis.starlark.StarlarkTransition;
import com.google.devtools.build.lib.analysis.test.CoverageReportActionFactory;
import com.google.devtools.build.lib.bugreport.BugReporter;
import com.google.devtools.build.lib.causes.Cause;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.events.ExtendedEventHandler;
import com.google.devtools.build.lib.events.StoredEventHandler;
import com.google.devtools.build.lib.packages.Attribute;
import com.google.devtools.build.lib.packages.BuildType;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.NoSuchTargetException;
import com.google.devtools.build.lib.packages.PackageSpecification;
import com.google.devtools.build.lib.packages.PackageSpecification.PackageGroupContents;
import com.google.devtools.build.lib.packages.RawAttributeMapper;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.skyframe.AspectKeyCreator;
import com.google.devtools.build.lib.skyframe.AspectKeyCreator.AspectKey;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetAndData;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetFunction;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetFunction.ComputedToolchainContexts;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
import com.google.devtools.build.lib.skyframe.PackageValue;
import com.google.devtools.build.lib.skyframe.SkyFunctionEnvironmentForTesting;
import com.google.devtools.build.lib.skyframe.SkyframeBuildView;
import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
import com.google.devtools.build.lib.skyframe.SkyframeExecutorWrappingWalkableGraph;
import com.google.devtools.build.lib.skyframe.StarlarkBuiltinsValue;
import com.google.devtools.build.lib.skyframe.TargetPatternPhaseValue;
import com.google.devtools.build.lib.skyframe.ToolchainException;
import com.google.devtools.build.lib.skyframe.UnloadedToolchainContext;
import com.google.devtools.build.lib.util.AbruptExitException;
import com.google.devtools.build.lib.util.OrderedSetMultimap;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.Version;
import com.google.devtools.build.skyframe.WalkableGraph;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import javax.annotation.Nullable;
import net.starlark.java.eval.Mutability;

/**
 * A util class that contains all the helper stuff previously in BuildView that only exists to give
 * tests access to Skyframe internals. The code largely predates the introduction of Skyframe, and
 * mostly exists to avoid having to rewrite our tests to work with Skyframe natively.
 */
public class BuildViewForTesting {
  private final BuildView buildView;
  private final SkyframeExecutor skyframeExecutor;
  private final SkyframeBuildView skyframeBuildView;

  private final ConfiguredRuleClassProvider ruleClassProvider;

  private ImmutableMap<ActionLookupKey, Version> currentActionLookupKeys = ImmutableMap.of();

  public BuildViewForTesting(
      BlazeDirectories directories,
      ConfiguredRuleClassProvider ruleClassProvider,
      SkyframeExecutor skyframeExecutor,
      CoverageReportActionFactory coverageReportActionFactory) {
    this.buildView =
        new BuildView(
            directories, ruleClassProvider, skyframeExecutor, coverageReportActionFactory);
    this.ruleClassProvider = ruleClassProvider;
    this.skyframeExecutor = Preconditions.checkNotNull(skyframeExecutor);
    this.skyframeBuildView = skyframeExecutor.getSkyframeBuildView();
  }

  Set<ActionLookupKey> getSkyframeEvaluatedActionLookupKeyCountForTesting() {
    Set<ActionLookupKey> actionLookupKeys = populateActionLookupKeyMapAndGetDiff();
    Preconditions.checkState(
        actionLookupKeys.size() == skyframeBuildView.getEvaluatedCounts().total(),
        "Number of newly evaluated action lookup values %s does not agree with number that changed"
            + " in graph: %s. Keys: %s",
        actionLookupKeys.size(),
        skyframeBuildView.getEvaluatedCounts().total(),
        actionLookupKeys);
    return actionLookupKeys;
  }

  private Set<ActionLookupKey> populateActionLookupKeyMapAndGetDiff() {
    ImmutableMap<ActionLookupKey, Version> newMap =
        skyframeExecutor.getEvaluator().getAllValuesMutable().entrySet().stream()
            .filter(e -> e.getKey() instanceof ActionLookupKey)
            .collect(
                toImmutableMap(e -> (ActionLookupKey) e.getKey(), e -> e.getValue().getVersion()));
    MapDifference<ActionLookupKey, Version> difference =
        Maps.difference(newMap, currentActionLookupKeys);
    currentActionLookupKeys = newMap;
    return Sets.union(
        difference.entriesDiffering().keySet(), difference.entriesOnlyOnLeft().keySet());
  }

  /** Returns whether the given configured target has errors. */
  public boolean hasErrors(ConfiguredTarget configuredTarget) {
    return configuredTarget == null;
  }

  @ThreadCompatible
  public AnalysisResult update(
      TargetPatternPhaseValue loadingResult,
      BuildOptions targetOptions,
      ImmutableSet<Label> explicitTargetPatterns,
      List<String> aspects,
      ImmutableMap<String, String> aspectsParameters,
      AnalysisOptions viewOptions,
      boolean keepGoing,
      int loadingPhaseThreads,
      TopLevelArtifactContext topLevelOptions,
      ExtendedEventHandler eventHandler,
      EventBus eventBus)
      throws ViewCreationFailedException, InterruptedException, InvalidConfigurationException,
          BuildFailedException, TestExecException, AbruptExitException {
    populateActionLookupKeyMapAndGetDiff();
    return buildView.update(
        loadingResult,
        targetOptions,
        explicitTargetPatterns,
        aspects,
        aspectsParameters,
        viewOptions,
        keepGoing,
        /*checkForActionConflicts=*/ true,
        loadingPhaseThreads,
        topLevelOptions,
        /*reportIncompatibleTargets=*/ true,
        eventHandler,
        eventBus,
        BugReporter.defaultInstance(),
        /*includeExecutionPhase=*/ false,
        /*mergedPhasesExecutionJobsCount=*/ 0,
        /*resourceManager=*/ null,
        /*buildResultListener=*/ null,
        /*executionSetupCallback=*/ null);
  }

  /** Sets the configurations. Not thread-safe. */
  public void setConfigurationsForTesting(
      EventHandler eventHandler, BuildConfigurationCollection configurations) {
    try {
      skyframeBuildView.setConfigurations(
          eventHandler, configurations, /* maxDifferencesToShow */ -1,
          /* allowAnalysisCacheDiscards */ true);
    } catch (InvalidConfigurationException e) {
      throw new UnsupportedOperationException(
          "InvalidConfigurationException was thrown and caught during a test, "
              + "this case is not yet handled",
          e);
    }
  }

  public ArtifactFactory getArtifactFactory() {
    return skyframeBuildView.getArtifactFactory();
  }

  /**
   * Gets a configuration for the given target.
   *
   * <p>Unconditionally includes all fragments.
   */
  public BuildConfigurationValue getConfigurationForTesting(
      Target target, BuildConfigurationValue config, ExtendedEventHandler eventHandler)
      throws InvalidConfigurationException, InterruptedException {
    List<TargetAndConfiguration> node =
        ImmutableList.of(new TargetAndConfiguration(target, config));
    Collection<TargetAndConfiguration> configs =
        ConfigurationResolver.getConfigurationsFromExecutor(
                node,
                AnalysisUtils.targetsToDeps(new LinkedHashSet<>(node), ruleClassProvider),
                eventHandler,
                skyframeExecutor)
            .getTargetsAndConfigs();
    return configs.iterator().next().getConfiguration();
  }

  /**
   * Sets the possible artifact roots in the artifact factory. This allows the factory to resolve
   * paths with unknown roots to artifacts.
   */
  public void setArtifactRoots(PackageRoots packageRoots) {
    getArtifactFactory().setPackageRoots(packageRoots.getPackageRootLookup());
  }

  // TODO(janakr): pass the configuration in as a parameter here.
  public Collection<ConfiguredTarget> getDirectPrerequisitesForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget ct,
      BuildConfigurationCollection configurations)
      throws DependencyResolver.Failure, InvalidConfigurationException,
          InconsistentAspectOrderException, StarlarkTransition.TransitionException {
    return Collections2.transform(
        getConfiguredTargetAndDataDirectPrerequisitesForTesting(eventHandler, ct, configurations),
        ConfiguredTargetAndData::getConfiguredTarget);
  }

  protected Collection<ConfiguredTargetAndData>
      getConfiguredTargetAndDataDirectPrerequisitesForTesting(
          ExtendedEventHandler eventHandler,
          ConfiguredTarget ct,
          BuildConfigurationCollection configurations)
          throws DependencyResolver.Failure, InvalidConfigurationException,
              InconsistentAspectOrderException, StarlarkTransition.TransitionException {

    SkyframeExecutorWrappingWalkableGraph walkableGraph =
        SkyframeExecutorWrappingWalkableGraph.of(skyframeExecutor);

    // Directly check the graph for the dependencies of the target.
    // This duplicates the logic in ConfiguredTargetFunction#computeDependencies without
    // actually recomputing anything, all values should be directly from skyframe.
    try {
      // Fetch the dependency keys. This is actually only needed to load the aspects for each
      // dependency.
      Multimap<Label, DependencyKey> dependencyKeys =
          getDirectPrerequisiteDependenciesForTesting(
                  eventHandler, ct, configurations, /* toolchainContexts= */ null)
              .values()
              .stream()
              .collect(
                  ImmutableListMultimap.toImmutableListMultimap(
                      DependencyKey::getLabel, Functions.identity()));

      // Load the keys of the dependencies of the target, based on data currently in skyframe.
      Iterable<SkyKey> directPrerequisites =
          walkableGraph.getDirectDeps(ConfiguredTargetKey.fromConfiguredTarget(ct));

      // Turn the keys back into ConfiguredTarget instances, possibly merging in aspects that were
      // propagated from the original target.
      return stream(Iterables.filter(directPrerequisites, ConfiguredTargetKey.class))
          .map(configuredTargetKey -> getConfiguredTarget(walkableGraph, configuredTargetKey))
          // For each configured target, add in any aspects from depNodeNames.
          .map(
              configuredTarget ->
                  mergeAspects(
                      walkableGraph,
                      configuredTarget,
                      findDependencyKey(dependencyKeys, configuredTarget)))
          .collect(toImmutableList());
    } catch (InterruptedException e) {
      return ImmutableList.of();
    }
  }

  // Helper method to look up a specific existing key in the graph, and handle the error condition.
  private static ConfiguredTargetAndData getConfiguredTarget(
      WalkableGraph graph, ConfiguredTargetKey key) {
    try {
      ConfiguredTargetValue value = (ConfiguredTargetValue) graph.getValue(key);
      if (value != null) {
        ConfiguredTarget ct = value.getConfiguredTarget();
        BuildConfigurationValue config = null;
        if (ct.getConfigurationKey() != null) {
          config = (BuildConfigurationValue) graph.getValue(ct.getConfigurationKey());
        }
        PackageValue packageValue =
            (PackageValue) graph.getValue(PackageValue.key(ct.getLabel().getPackageIdentifier()));
        return new ConfiguredTargetAndData(
            ct,
            packageValue.getPackage().getTarget(ct.getLabel().getName()),
            config,
            /* transitionKeys= */ null);
      }
      return null;
    } catch (InterruptedException | NoSuchTargetException e) {
      throw new IllegalStateException("Unexpected error retrieving keys from graph", e);
    }
  }

  @Nullable
  private static DependencyKey findDependencyKey(
      Multimap<Label, DependencyKey> dependencyKeys, ConfiguredTargetAndData configuredTarget) {
    // TODO(blaze-configurability): Figure out how to map the ConfiguredTarget back to the correct
    // DependencyKey when there are more than one.
    return Iterables.getFirst(dependencyKeys.get(configuredTarget.getTarget().getLabel()), null);
  }

  // Helper method to find the aspects needed for a target and merge them.
  protected static ConfiguredTargetAndData mergeAspects(
      WalkableGraph graph, ConfiguredTargetAndData ctd, @Nullable DependencyKey dependencyKey) {
    if (dependencyKey == null || dependencyKey.getAspects().getUsedAspects().isEmpty()) {
      return ctd;
    }

    ConfiguredTargetKey ctKey =
        ConfiguredTargetKey.builder()
            .setLabel(dependencyKey.getLabel())
            .setConfiguration(ctd.getConfiguration())
            .build();
    List<SkyKey> aspectKeys =
        dependencyKey.getAspects().getUsedAspects().stream()
            .map(aspect -> AspectKeyCreator.createAspectKey(aspect.getAspect(), ctKey))
            .collect(toImmutableList());

    try {
      ImmutableList<ConfiguredAspect> configuredAspects =
          graph.getSuccessfulValues(aspectKeys).values().stream()
              .map(value -> (AspectValue) value)
              .map(AspectValue::getConfiguredAspect)
              .collect(toImmutableList());

      return ctd.fromConfiguredTarget(
          MergedConfiguredTarget.of(ctd.getConfiguredTarget(), configuredAspects));
    } catch (InterruptedException | DuplicateException e) {
      throw new IllegalStateException("Unexpected exception while finding prerequisites", e);
    }
  }

  public OrderedSetMultimap<DependencyKind, DependencyKey>
      getDirectPrerequisiteDependenciesForTesting(
          final ExtendedEventHandler eventHandler,
          final ConfiguredTarget ct,
          BuildConfigurationCollection configurations,
          @Nullable ToolchainCollection<ToolchainContext> toolchainContexts)
          throws DependencyResolver.Failure, InterruptedException, InconsistentAspectOrderException,
              StarlarkTransition.TransitionException, InvalidConfigurationException {

    Target target;
    try {
      target = skyframeExecutor.getPackageManager().getTarget(eventHandler, ct.getLabel());
    } catch (NoSuchPackageException | NoSuchTargetException | InterruptedException e) {
      eventHandler.handle(
          Event.error("Failed to get target from package during prerequisite analysis." + e));
      return OrderedSetMultimap.create();
    }

    if (!(target instanceof Rule)) {
      return OrderedSetMultimap.create();
    }

    class SilentDependencyResolver extends DependencyResolver {
      private SilentDependencyResolver() {}

      @Override
      protected Map<Label, Target> getTargets(
          OrderedSetMultimap<DependencyKind, Label> labelMap,
          TargetAndConfiguration fromNode,
          NestedSetBuilder<Cause> rootCauses) {
        return labelMap.values().stream()
            .distinct()
            .collect(
                Collectors.toMap(
                    Function.identity(),
                    label -> {
                      try {
                        return skyframeExecutor.getPackageManager().getTarget(eventHandler, label);
                      } catch (NoSuchPackageException
                          | NoSuchTargetException
                          | InterruptedException e) {
                        throw new IllegalStateException(e);
                      }
                    }));
      }
    }

    DependencyResolver dependencyResolver = new SilentDependencyResolver();
    BuildConfigurationValue configuration =
        skyframeExecutor.getConfiguration(eventHandler, ct.getConfigurationKey());
    TargetAndConfiguration ctgNode = new TargetAndConfiguration(target, configuration);
    return dependencyResolver.dependentNodeMap(
        ctgNode,
        /*aspect=*/ null,
        getConfigurableAttributeKeysForTesting(
            eventHandler,
            ctgNode,
            toolchainContexts == null ? null : toolchainContexts.getTargetPlatform()),
        toolchainContexts,
        ruleClassProvider.getTrimmingTransitionFactory());
  }

  /**
   * Returns ConfigMatchingProvider instances corresponding to the configurable attribute keys
   * present in this rule's attributes.
   */
  private ImmutableMap<Label, ConfigMatchingProvider> getConfigurableAttributeKeysForTesting(
      ExtendedEventHandler eventHandler,
      TargetAndConfiguration ctg,
      @Nullable PlatformInfo platformInfo)
      throws StarlarkTransition.TransitionException, InvalidConfigurationException,
          InterruptedException {
    if (!(ctg.getTarget() instanceof Rule)) {
      return ImmutableMap.of();
    }
    Rule rule = (Rule) ctg.getTarget();
    Map<Label, ConfigMatchingProvider> keys = new LinkedHashMap<>();
    RawAttributeMapper mapper = RawAttributeMapper.of(rule);
    for (Attribute attribute : rule.getAttributes()) {
      for (Label label : mapper.getConfigurabilityKeys(attribute.getName(), attribute.getType())) {
        if (BuildType.Selector.isDefaultConditionLabel(label)) {
          continue;
        }
        ConfiguredTarget ct =
            getConfiguredTargetForTesting(eventHandler, label, ctg.getConfiguration());
        ConfigMatchingProvider matchProvider = ct.getProvider(ConfigMatchingProvider.class);
        ConstraintValueInfo constraintValueInfo = ct.get(ConstraintValueInfo.PROVIDER);
        if (matchProvider != null) {
          keys.put(label, matchProvider);
        } else if (constraintValueInfo != null && platformInfo != null) {
          keys.put(label, constraintValueInfo.configMatchingProvider(platformInfo));
        } else {
          throw new InvalidConfigurationException(
              String.format("%s isn't a valid select() condition", label));
        }
      }
    }
    return ImmutableMap.copyOf(keys);
  }

  private OrderedSetMultimap<DependencyKind, ConfiguredTargetAndData> getPrerequisiteMapForTesting(
      final ExtendedEventHandler eventHandler,
      ConfiguredTarget target,
      BuildConfigurationCollection configurations,
      @Nullable ToolchainCollection<ToolchainContext> toolchainContexts)
      throws DependencyResolver.Failure, InvalidConfigurationException, InterruptedException,
          InconsistentAspectOrderException, StarlarkTransition.TransitionException {
    OrderedSetMultimap<DependencyKind, DependencyKey> depNodeNames =
        getDirectPrerequisiteDependenciesForTesting(
            eventHandler, target, configurations, toolchainContexts);

    ImmutableMultimap<DependencyKey, ConfiguredTargetAndData> cts =
        skyframeExecutor.getConfiguredTargetMapForTesting(
            eventHandler, target.getConfigurationKey(), ImmutableSet.copyOf(depNodeNames.values()));

    OrderedSetMultimap<DependencyKind, ConfiguredTargetAndData> result =
        OrderedSetMultimap.create();
    for (Map.Entry<DependencyKind, DependencyKey> entry : depNodeNames.entries()) {
      result.putAll(entry.getKey(), cts.get(entry.getValue()));
    }
    return result;
  }

  private ConfigurationTransition getTopLevelTransitionForTarget(
      Label label, BuildConfigurationValue config, ExtendedEventHandler handler) {
    Target target;
    try {
      target = skyframeExecutor.getPackageManager().getTarget(handler, label);
    } catch (NoSuchPackageException | NoSuchTargetException e) {
      // TODO(bazel-team): refactor this method so we actually throw an exception here (likely
      // {@link TransitionException}. Every version of getConfiguredTarget runs through this
      // method and many test cases rely on not erroring out here so be able to reach an error
      // later on.
      return NoTransition.INSTANCE;
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      throw new AssertionError("Configuration of " + label + " interrupted");
    }
    // Return early if a rule target is in error. We don't want whatever caused the rule error to
    // also cause problems in computing the transition (e.g. an unchecked exception).
    if (target instanceof Rule && ((Rule) target).containsErrors()) {
      return null;
    }
    return TransitionResolver.evaluateTransition(
        config, NoTransition.INSTANCE, target, ruleClassProvider.getTrimmingTransitionFactory());
  }

  /**
   * Returns a configured target for the specified target and configuration. If the target in
   * question has a top-level rule class transition, that transition is applied in the returned
   * ConfiguredTarget.
   *
   * <p>Returns {@code null} if something goes wrong.
   */
  public ConfiguredTarget getConfiguredTargetForTesting(
      ExtendedEventHandler eventHandler, Label label, BuildConfigurationValue config)
      throws StarlarkTransition.TransitionException, InvalidConfigurationException,
          InterruptedException {
    ConfigurationTransition transition =
        getTopLevelTransitionForTarget(label, config, eventHandler);
    if (transition == null) {
      return null;
    }
    return skyframeExecutor.getConfiguredTargetForTesting(eventHandler, label, config, transition);
  }

  ConfiguredTargetAndData getConfiguredTargetAndDataForTesting(
      ExtendedEventHandler eventHandler, Label label, BuildConfigurationValue config)
      throws StarlarkTransition.TransitionException, InvalidConfigurationException,
          InterruptedException {
    ConfigurationTransition transition =
        getTopLevelTransitionForTarget(label, config, eventHandler);
    if (transition == null) {
      return null;
    }
    return skyframeExecutor.getConfiguredTargetAndDataForTesting(
        eventHandler, label, config, transition);
  }

  /**
   * Returns a RuleContext which is the same as the original RuleContext of the target parameter.
   */
  public RuleContext getRuleContextForTesting(
      ConfiguredTarget target,
      StoredEventHandler eventHandler,
      BuildConfigurationCollection configurations)
      throws DependencyResolver.Failure, InvalidConfigurationException, InterruptedException,
          InconsistentAspectOrderException, ToolchainException,
          StarlarkTransition.TransitionException, InvalidExecGroupException {
    BuildConfigurationValue targetConfig =
        skyframeExecutor.getConfiguration(eventHandler, target.getConfigurationKey());
    SkyFunction.Environment skyframeEnv =
        new SkyFunctionEnvironmentForTesting(eventHandler, skyframeExecutor);
    StarlarkBuiltinsValue starlarkBuiltinsValue =
        (StarlarkBuiltinsValue)
            Preconditions.checkNotNull(skyframeEnv.getValue(StarlarkBuiltinsValue.key()));
    CachingAnalysisEnvironment analysisEnv =
        new CachingAnalysisEnvironment(
            getArtifactFactory(),
            skyframeExecutor.getActionKeyContext(),
            ConfiguredTargetKey.builder()
                .setLabel(target.getLabel())
                .setConfiguration(targetConfig)
                .build(),
            targetConfig.extendedSanityChecks(),
            targetConfig.allowAnalysisFailures(),
            eventHandler,
            skyframeEnv,
            starlarkBuiltinsValue);
    return getRuleContextForTesting(eventHandler, target, analysisEnv, configurations);
  }

  /**
   * Creates and returns a rule context that is equivalent to the one that was used to create the
   * given configured target.
   */
  public RuleContext getRuleContextForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget configuredTarget,
      AnalysisEnvironment env,
      BuildConfigurationCollection configurations)
      throws DependencyResolver.Failure, InvalidConfigurationException, InterruptedException,
          InconsistentAspectOrderException, ToolchainException,
          StarlarkTransition.TransitionException, InvalidExecGroupException {
    BuildConfigurationValue targetConfig =
        skyframeExecutor.getConfiguration(eventHandler, configuredTarget.getConfigurationKey());
    Target target;
    try {
      target =
          skyframeExecutor.getPackageManager().getTarget(eventHandler, configuredTarget.getLabel());
    } catch (NoSuchPackageException | NoSuchTargetException e) {
      eventHandler.handle(
          Event.error("Failed to get target when trying to get rule context for testing"));
      throw new IllegalStateException(e);
    }

    SkyFunctionEnvironmentForTesting skyfunctionEnvironment =
        new SkyFunctionEnvironmentForTesting(eventHandler, skyframeExecutor);

    ComputedToolchainContexts result =
        ConfiguredTargetFunction.computeUnloadedToolchainContexts(
            skyfunctionEnvironment,
            ruleClassProvider,
            new TargetAndConfiguration(target.getAssociatedRule(), targetConfig),
            null);

    ToolchainCollection<UnloadedToolchainContext> unloadedToolchainCollection =
        result.toolchainCollection;
    ExecGroupCollection.Builder execGroupCollectionBuilder = result.execGroupCollectionBuilder;

    OrderedSetMultimap<DependencyKind, ConfiguredTargetAndData> prerequisiteMap =
        getPrerequisiteMapForTesting(
            eventHandler,
            configuredTarget,
            configurations,
            unloadedToolchainCollection.asToolchainContexts());
    String targetDescription = target.toString();

    ToolchainCollection.Builder<ResolvedToolchainContext> resolvedToolchainContext =
        ToolchainCollection.builder();
    for (Map.Entry<String, UnloadedToolchainContext> unloadedToolchainContext :
        unloadedToolchainCollection.getContextMap().entrySet()) {
      ResolvedToolchainContext toolchainContext =
          ResolvedToolchainContext.load(
              unloadedToolchainContext.getValue(),
              targetDescription,
              prerequisiteMap.get(DependencyKind.forExecGroup(unloadedToolchainContext.getKey())));
      resolvedToolchainContext.addContext(unloadedToolchainContext.getKey(), toolchainContext);
    }

    return new RuleContext.Builder(env, target, /*aspects=*/ ImmutableList.of(), targetConfig)
        .setRuleClassProvider(ruleClassProvider)
        .setHostConfiguration(configurations.getHostConfiguration())
        .setConfigurationFragmentPolicy(
            target.getAssociatedRule().getRuleClassObject().getConfigurationFragmentPolicy())
        .setActionOwnerSymbol(ConfiguredTargetKey.fromConfiguredTarget(configuredTarget))
        .setMutability(Mutability.create("configured target"))
        .setVisibility(
            NestedSetBuilder.create(
                Order.STABLE_ORDER,
                PackageGroupContents.create(ImmutableList.of(PackageSpecification.everything()))))
        .setPrerequisites(ConfiguredTargetFactory.transformPrerequisiteMap(prerequisiteMap))
        .setConfigConditions(ConfigConditions.EMPTY)
        .setToolchainContexts(resolvedToolchainContext.build())
        .setExecGroupCollectionBuilder(execGroupCollectionBuilder)
        .unsafeBuild();
  }

  /** Clears the analysis cache as in --discard_analysis_cache. */
  void clearAnalysisCache(
      ImmutableSet<ConfiguredTarget> topLevelTargets, ImmutableSet<AspectKey> topLevelAspects) {
    skyframeBuildView.clearAnalysisCache(topLevelTargets, topLevelAspects);
  }
}