src/test/java/com/google/devtools/build/lib/remote/RemoteOutputCheckerTest.java

// Copyright 2025 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.remote;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.ArtifactRoot;
import com.google.devtools.build.lib.actions.FileArtifactValue;
import com.google.devtools.build.lib.actions.util.ActionsTestUtil;
import com.google.devtools.build.lib.remote.options.RemoteOutputsMode;
import com.google.devtools.build.lib.vfs.DigestHashFunction;
import com.google.devtools.build.lib.vfs.FileSystem;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link RemoteOutputChecker} */
@RunWith(JUnit4.class)
public class RemoteOutputCheckerTest {
  private final RemoteOutputChecker remoteOutputChecker =
      new RemoteOutputChecker("build", RemoteOutputsMode.MINIMAL, ImmutableList.of());
  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
  private final ArtifactRoot execRoot =
      ArtifactRoot.asDerivedRoot(fs.getPath("/execroot"), ArtifactRoot.RootType.OUTPUT, "out");

  @Test
  public void testShouldDownloadOutput() {
    remoteOutputChecker.addOutputToDownload(
        ActionsTestUtil.createTreeArtifactWithGeneratingAction(execRoot, "foo/bar"));
    remoteOutputChecker.addOutputToDownload(
        ActionsTestUtil.createArtifact(execRoot, "foo/bar-baz"));
    assertThat(
            remoteOutputChecker.shouldDownloadOutput(PathFragment.create("out/foo/bar-quz"), null))
        .isFalse();
    assertThat(remoteOutputChecker.shouldDownloadOutput(PathFragment.create("out/foo/bar"), null))
        .isTrue();
    assertThat(
            remoteOutputChecker.shouldDownloadOutput(
                PathFragment.create("out/foo/bar/data.txt"), PathFragment.create("out/foo/bar")))
        .isTrue();
    assertThat(
            remoteOutputChecker.shouldDownloadOutput(PathFragment.create("out/foo/bar-baz"), null))
        .isTrue();
  }

  @Test
  public void shouldTrustMetadata_previousBuildDownloadedAll_trusted() {
    // Outputs that the current build does not want downloaded must not be distrusted
    // due to a previous invocation using a broader download policy.
    Artifact artifact = ActionsTestUtil.createArtifact(execRoot, "foo/bar");
    FileArtifactValue metadata =
        FileArtifactValue.createForRemoteFile(
            new byte[] {1, 2, 3}, /* size= */ 3, /* locationIndex= */ 1);

    var previousBuildChecker =
        new RemoteOutputChecker("build", RemoteOutputsMode.ALL, ImmutableList.of());
    var currentBuildChecker =
        new RemoteOutputChecker(
            "build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of(), previousBuildChecker);

    assertThat(currentBuildChecker.shouldTrustMetadata(artifact, metadata)).isTrue();
  }

  @Test
  public void shouldTrustMetadata_previousBuildRegexMatch_trusted() {
    Artifact artifact = ActionsTestUtil.createArtifact(execRoot, "foo/bar");
    FileArtifactValue metadata =
        FileArtifactValue.createForRemoteFile(
            new byte[] {1, 2, 3}, /* size= */ 3, /* locationIndex= */ 1);

    var previousBuildChecker =
        new RemoteOutputChecker(
            "build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of(unused -> true));
    var currentBuildChecker =
        new RemoteOutputChecker(
            "build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of(), previousBuildChecker);

    assertThat(currentBuildChecker.shouldTrustMetadata(artifact, metadata)).isTrue();
  }

  @Test
  public void shouldTrustMetadata_toplevelOutputOfPreviousBuild_distrusted() {
    // A toplevel output downloaded by the previous build must be distrusted if missing locally, so
    // that the generating action reruns to restore it. Under Skymeld, the current build's toplevel
    // outputs are not yet registered when this check runs.
    Artifact artifact = ActionsTestUtil.createArtifact(execRoot, "foo/bar");
    FileArtifactValue metadata =
        FileArtifactValue.createForRemoteFile(
            new byte[] {1, 2, 3}, /* size= */ 3, /* locationIndex= */ 1);

    var previousBuildChecker =
        new RemoteOutputChecker("build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of());
    previousBuildChecker.addOutputToDownload(artifact);
    var currentBuildChecker =
        new RemoteOutputChecker(
            "build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of(), previousBuildChecker);

    assertThat(currentBuildChecker.shouldTrustMetadata(artifact, metadata)).isFalse();
  }

  @Test
  public void shouldTrustMetadata_downloadedByCurrentBuild_distrusted() {
    Artifact artifact = ActionsTestUtil.createArtifact(execRoot, "foo/bar");
    FileArtifactValue metadata =
        FileArtifactValue.createForRemoteFile(
            new byte[] {1, 2, 3}, /* size= */ 3, /* locationIndex= */ 1);

    var previousBuildChecker =
        new RemoteOutputChecker("build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of());
    var currentBuildChecker =
        new RemoteOutputChecker(
            "build", RemoteOutputsMode.TOPLEVEL, ImmutableList.of(), previousBuildChecker);
    currentBuildChecker.addOutputToDownload(artifact);

    assertThat(currentBuildChecker.shouldTrustMetadata(artifact, metadata)).isFalse();
  }
}