com.google.devtools.build.lib.skyframe.TransitiveTargetCycleReporter.java Source code

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Here is the source code for com.google.devtools.build.lib.skyframe.TransitiveTargetCycleReporter.java

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// Copyright 2014 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.skyframe;

import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.packages.PackageGroup;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.pkgcache.PackageProvider;
import com.google.devtools.build.skyframe.CycleInfo;
import com.google.devtools.build.skyframe.SkyKey;

import java.util.List;

/**
 * Reports cycles between {@link TransitiveTargetValue}s. These indicates cycles between targets
 * (e.g. '//a:foo' depends on '//b:bar' and '//b:bar' depends on '//a:foo').
 */
class TransitiveTargetCycleReporter extends AbstractLabelCycleReporter {

    private static final Predicate<SkyKey> IS_TRANSITIVE_TARGET_SKY_KEY = SkyFunctions
            .isSkyFunction(SkyFunctions.TRANSITIVE_TARGET);

    TransitiveTargetCycleReporter(PackageProvider packageProvider) {
        super(packageProvider);
    }

    @Override
    protected boolean canReportCycle(SkyKey topLevelKey, CycleInfo cycleInfo) {
        return Iterables.all(
                Iterables.concat(ImmutableList.of(topLevelKey), cycleInfo.getPathToCycle(), cycleInfo.getCycle()),
                IS_TRANSITIVE_TARGET_SKY_KEY);
    }

    @Override
    public String prettyPrint(SkyKey key) {
        return getLabel(key).toString();
    }

    @Override
    protected Label getLabel(SkyKey key) {
        return (Label) key.argument();
    }

    @Override
    protected String getAdditionalMessageAboutCycle(EventHandler eventHandler, SkyKey topLevelKey,
            CycleInfo cycleInfo) {
        Target currentTarget = getTargetForLabel(eventHandler, getLabel(topLevelKey));
        List<SkyKey> keys = Lists.newArrayList();
        if (!cycleInfo.getPathToCycle().isEmpty()) {
            keys.add(topLevelKey);
            keys.addAll(cycleInfo.getPathToCycle());
        }
        keys.addAll(cycleInfo.getCycle());
        // Make sure we check the edge from the last element of the cycle to the first element of the
        // cycle.
        keys.add(cycleInfo.getCycle().get(0));
        for (SkyKey nextKey : keys) {
            Label nextLabel = getLabel(nextKey);
            Target nextTarget = getTargetForLabel(eventHandler, nextLabel);
            // This is inefficient but it's no big deal since we only do this when there's a cycle.
            if (currentTarget.getVisibility().getDependencyLabels().contains(nextLabel)
                    && !nextTarget.getTargetKind().equals(PackageGroup.targetKind())) {
                return "\nThe cycle is caused by a visibility edge from " + currentTarget.getLabel()
                        + " to the non-package-group target " + nextTarget.getLabel() + " . Note that "
                        + "visibility labels are supposed to be package group targets (which prevents cycles "
                        + "of this form)";
            }
            currentTarget = nextTarget;
        }
        return "";
    }
}