diff --git a/src/main/java/com/google/devtools/build/lib/actions/CompletionContext.java b/src/main/java/com/google/devtools/build/lib/actions/CompletionContext.java
index 9adb7c1..12df48a 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/CompletionContext.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/CompletionContext.java
@@ -25,6 +25,7 @@
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.Map;
+import javax.annotation.Nullable;
 
 /**
  * Container for the data one needs to resolve aggregate artifacts from events signaling the
@@ -104,16 +105,13 @@
     return pathResolver;
   }
 
+  @Nullable
+  public FileArtifactValue getFileArtifactValue(Artifact artifact) {
+    return importantInputMap.getMetadata(artifact);
+  }
+
   /** Returns true if the given artifact is guaranteed to be a file (and not a directory). */
-  public boolean isGuaranteedToBeOutputFile(Artifact artifact) {
-    FileArtifactValue metadata = importantInputMap.getMetadata(artifact);
-    // If we have no metadata for an output file that will be reported in BEP, return that the
-    // output is not guaranteed to be a file. (We expect this to happen for baseline_coverage.dat
-    // files when coverage is enabled.)
-    if (metadata == null) {
-      return false;
-    }
-    FileStateType type = metadata.getType();
+  public static boolean isGuaranteedToBeOutputFile(FileStateType type) {
     return type == FileStateType.REGULAR_FILE
         || type == FileStateType.SPECIAL_FILE
         || type == FileStateType.NONEXISTENT;
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BUILD b/src/main/java/com/google/devtools/build/lib/analysis/BUILD
index 7eef655..b4084ca 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BUILD
@@ -374,6 +374,7 @@
         "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
         "//src/main/java/com/google/devtools/build/lib/actions:commandline_item",
         "//src/main/java/com/google/devtools/build/lib/actions:execution_requirements",
+        "//src/main/java/com/google/devtools/build/lib/actions:file_metadata",
         "//src/main/java/com/google/devtools/build/lib/actions:fileset_output_symlink",
         "//src/main/java/com/google/devtools/build/lib/actions:localhost_capacity",
         "//src/main/java/com/google/devtools/build/lib/actions:package_roots",
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/TargetCompleteEvent.java b/src/main/java/com/google/devtools/build/lib/analysis/TargetCompleteEvent.java
index 9c54ee9..8fc1c54 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/TargetCompleteEvent.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/TargetCompleteEvent.java
@@ -23,10 +23,12 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
+import com.google.common.io.BaseEncoding;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.CompletionContext;
 import com.google.devtools.build.lib.actions.CompletionContext.ArtifactReceiver;
 import com.google.devtools.build.lib.actions.EventReportingArtifacts;
+import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.analysis.TopLevelArtifactHelper.ArtifactsInOutputGroup;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
@@ -110,6 +112,8 @@
     }
   }
 
+  private static final BaseEncoding LOWERCASE_HEX_ENCODING = BaseEncoding.base16().lowerCase();
+
   private final Label label;
   private final ConfiguredTargetKey configuredTargetKey;
   private final NestedSet<Cause> rootCauses;
@@ -337,7 +341,8 @@
             String uri =
                 converters.pathConverter().apply(completionContext.pathResolver().toPath(artifact));
             if (uri != null) {
-              builder.addImportantOutput(newFileFromArtifact(name, artifact).setUri(uri).build());
+              builder.addImportantOutput(
+                  newFileFromArtifact(name, artifact, completionContext).setUri(uri).build());
             }
           }
 
@@ -354,12 +359,12 @@
   }
 
   public static BuildEventStreamProtos.File.Builder newFileFromArtifact(
-      String name, Artifact artifact) {
-    return newFileFromArtifact(name, artifact, PathFragment.EMPTY_FRAGMENT);
+      String name, Artifact artifact, CompletionContext completionContext) {
+    return newFileFromArtifact(name, artifact, PathFragment.EMPTY_FRAGMENT, completionContext);
   }
 
   public static BuildEventStreamProtos.File.Builder newFileFromArtifact(
-      String name, Artifact artifact, PathFragment relPath) {
+      String name, Artifact artifact, PathFragment relPath, CompletionContext completionContext) {
     if (name == null) {
       name = artifact.getRootRelativePath().getRelative(relPath).getPathString();
       if (OS.getCurrent() != OS.WINDOWS) {
@@ -373,13 +378,24 @@
         name = new String(name.getBytes(ISO_8859_1), UTF_8);
       }
     }
-    return File.newBuilder()
-        .setName(name)
-        .addAllPathPrefix(artifact.getRoot().getExecPath().segments());
+    File.Builder file =
+        File.newBuilder()
+            .setName(name)
+            .addAllPathPrefix(artifact.getRoot().getExecPath().segments());
+    FileArtifactValue fileArtifactValue = completionContext.getFileArtifactValue(artifact);
+    if (fileArtifactValue != null && fileArtifactValue.getType().exists()) {
+      byte[] digest = fileArtifactValue.getDigest();
+      if (digest != null) {
+        file.setDigest(LOWERCASE_HEX_ENCODING.encode(digest));
+      }
+      file.setLength(fileArtifactValue.getSize());
+    }
+    return file;
   }
 
-  public static BuildEventStreamProtos.File.Builder newFileFromArtifact(Artifact artifact) {
-    return newFileFromArtifact(/* name= */ null, artifact);
+  public static BuildEventStreamProtos.File.Builder newFileFromArtifact(
+      Artifact artifact, CompletionContext completionContext) {
+    return newFileFromArtifact(/* name= */ null, artifact, completionContext);
   }
 
   @Override
@@ -444,7 +460,7 @@
     Iterable<Artifact> filteredImportantArtifacts = getLegacyFilteredImportantArtifacts();
     for (Artifact artifact : filteredImportantArtifacts) {
       if (artifact.isDirectory()) {
-        builder.addDirectoryOutput(newFileFromArtifact(artifact).build());
+        builder.addDirectoryOutput(newFileFromArtifact(artifact, completionContext).build());
       }
     }
     // TODO(aehlig): remove direct reporting of artifacts as soon as clients no longer need it.
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.proto b/src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.proto
index e9e0058..6da5620 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.proto
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.proto
@@ -479,6 +479,13 @@
     // The contents of the file, if they are guaranteed to be short.
     bytes contents = 3;
   }
+
+  // Digest of the file, using the build tool's configured digest algorithm,
+  // hex-encoded.
+  string digest = 5;
+
+  // Length of the file in bytes.
+  int64 length = 6;
 }
 
 // Payload of a message to describe a set of files, usually build artifacts, to
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/NamedArtifactGroup.java b/src/main/java/com/google/devtools/build/lib/runtime/NamedArtifactGroup.java
index 75d56fa..6c0439e 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/NamedArtifactGroup.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/NamedArtifactGroup.java
@@ -14,6 +14,7 @@
 
 package com.google.devtools.build.lib.runtime;
 
+import static com.google.devtools.build.lib.actions.CompletionContext.isGuaranteedToBeOutputFile;
 import static com.google.devtools.build.lib.analysis.TargetCompleteEvent.newFileFromArtifact;
 
 import com.google.common.collect.ImmutableList;
@@ -21,6 +22,7 @@
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.CompletionContext;
 import com.google.devtools.build.lib.actions.CompletionContext.ArtifactReceiver;
+import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.buildeventstream.ArtifactGroupNamer;
 import com.google.devtools.build.lib.buildeventstream.BuildEvent;
 import com.google.devtools.build.lib.buildeventstream.BuildEvent.LocalFile.LocalFileType;
@@ -74,8 +76,10 @@
     for (Object elem : set.getLeaves()) {
       ExpandedArtifact expandedArtifact = (ExpandedArtifact) elem;
       if (expandedArtifact.relPath == null) {
+        FileArtifactValue fileMetadata =
+            completionContext.getFileArtifactValue(expandedArtifact.artifact);
         LocalFileType outputType =
-            completionContext.isGuaranteedToBeOutputFile(expandedArtifact.artifact)
+            fileMetadata != null && isGuaranteedToBeOutputFile(fileMetadata.getType())
                 ? LocalFileType.OUTPUT_FILE
                 : LocalFileType.OUTPUT;
         artifacts.add(
@@ -104,7 +108,8 @@
         String uri =
             pathConverter.apply(completionContext.pathResolver().toPath(expandedArtifact.artifact));
         if (uri != null) {
-          builder.addFiles(newFileFromArtifact(expandedArtifact.artifact).setUri(uri));
+          builder.addFiles(
+              newFileFromArtifact(expandedArtifact.artifact, completionContext).setUri(uri));
         }
       } else {
         String uri =
@@ -112,9 +117,9 @@
                 completionContext.pathResolver().convertPath(expandedArtifact.target));
         if (uri != null) {
           builder.addFiles(
-              newFileFromArtifact(null, expandedArtifact.artifact, expandedArtifact.relPath)
-                  .setUri(uri)
-                  .build());
+              newFileFromArtifact(
+                      null, expandedArtifact.artifact, expandedArtifact.relPath, completionContext)
+                  .setUri(uri));
         }
       }
     }
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/TargetCompleteEventTest.java b/src/test/java/com/google/devtools/build/lib/analysis/TargetCompleteEventTest.java
index 4c8fd7f..653085a 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/TargetCompleteEventTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/TargetCompleteEventTest.java
@@ -15,13 +15,13 @@
 package com.google.devtools.build.lib.analysis;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.devtools.build.lib.actions.CompletionContext.FAILED_COMPLETION_CTX;
 import static com.google.devtools.build.lib.analysis.TargetCompleteEvent.newFileFromArtifact;
 import static java.nio.charset.StandardCharsets.ISO_8859_1;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
-import com.google.devtools.build.lib.actions.CompletionContext;
 import com.google.devtools.build.lib.actions.EventReportingArtifacts.ReportedArtifacts;
 import com.google.devtools.build.lib.analysis.TopLevelArtifactHelper.ArtifactsToBuild;
 import com.google.devtools.build.lib.analysis.util.AnalysisTestCase;
@@ -65,7 +65,7 @@
     TargetCompleteEvent event =
         TargetCompleteEvent.successfulBuild(
             ctAndData,
-            CompletionContext.FAILED_COMPLETION_CTX,
+            FAILED_COMPLETION_CTX,
             artifactsToBuild.getAllArtifactsByOutputGroup(),
             /*announceTargetSummary=*/ false);
 
@@ -73,7 +73,9 @@
     ReportedArtifacts reportedArtifacts = event.reportedArtifacts();
     for (NestedSet<Artifact> artifactSet : reportedArtifacts.artifacts) {
       for (Artifact a : artifactSet.toListInterruptibly()) {
-        fileProtos.add(newFileFromArtifact(null, a, PathFragment.EMPTY_FRAGMENT).build());
+        fileProtos.add(
+            newFileFromArtifact(null, a, PathFragment.EMPTY_FRAGMENT, FAILED_COMPLETION_CTX)
+                .build());
       }
     }
     // Bytes are the same but the encoding is actually UTF-8 as required of a protobuf string.
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/BUILD b/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
index c6f3026..b06c6b8 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
@@ -551,21 +551,28 @@
 )
 
 java_test(
-    name = "TargetCompleteEventKeepsMinimalMetadataTest",
-    srcs = ["TargetCompleteEventKeepsMinimalMetadataTest.java"],
+    name = "TargetCompleteEventTest",
+    srcs = ["TargetCompleteEventTest.java"],
     tags = [
         "no_windows",
     ],
     deps = [
         "//src/main/java/com/google/devtools/build/lib:runtime",
+        "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
+        "//src/main/java/com/google/devtools/build/lib/actions:file_metadata",
         "//src/main/java/com/google/devtools/build/lib/analysis:analysis_cluster",
         "//src/main/java/com/google/devtools/build/lib/analysis:configured_target",
+        "//src/main/java/com/google/devtools/build/lib/buildeventservice",
+        "//src/main/java/com/google/devtools/build/lib/buildeventstream/proto:build_event_stream_java_proto",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/collect/nestedset",
+        "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/test/java/com/google/devtools/build/lib/analysis/util",
         "//src/test/java/com/google/devtools/build/lib/buildtool/util",
+        "//src/test/java/com/google/devtools/build/lib/packages:testutil",
         "//third_party:guava",
+        "//third_party:jsr305",
         "//third_party:junit4",
         "//third_party:truth",
     ],
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventKeepsMinimalMetadataTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventKeepsMinimalMetadataTest.java
deleted file mode 100644
index d26ccb8..0000000
--- a/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventKeepsMinimalMetadataTest.java
+++ /dev/null
@@ -1,138 +0,0 @@
-// Copyright 2021 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.buildtool;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import com.google.common.collect.Iterables;
-import com.google.common.eventbus.Subscribe;
-import com.google.devtools.build.lib.actions.Artifact;
-import com.google.devtools.build.lib.analysis.ConfiguredTarget;
-import com.google.devtools.build.lib.analysis.OutputGroupInfo;
-import com.google.devtools.build.lib.analysis.TargetCompleteEvent;
-import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
-import com.google.devtools.build.lib.analysis.util.AnalysisMock;
-import com.google.devtools.build.lib.buildtool.util.BuildIntegrationTestCase;
-import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.collect.nestedset.NestedSet;
-import java.util.Collection;
-import java.util.concurrent.atomic.AtomicReference;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-/**
- * Validates that TargetCompleteEvents do not keep a map of action output metadata for the
- * _validation output group, which can be quite large.
- */
-@RunWith(JUnit4.class)
-public class TargetCompleteEventKeepsMinimalMetadataTest extends BuildIntegrationTestCase {
-
-  @Before
-  public void stageEmbeddedTools() throws Exception {
-    AnalysisMock.get().setupMockToolsRepository(mockToolsConfig);
-  }
-
-  @Test
-  public void artifactsNotRetained() throws Exception {
-    write(
-        "validation_actions/defs.bzl",
-        "def _rule_with_implicit_outs_and_validation_impl(ctx):",
-        "",
-        "  ctx.actions.write(ctx.outputs.main, \"main output\\n\")",
-        "",
-        "  ctx.actions.write(ctx.outputs.implicit, \"implicit output\\n\")",
-        "",
-        "  validation_output = ctx.actions.declare_file(ctx.attr.name + \".validation\")",
-        "  # The actual tool will be created in individual tests, depending on whether",
-        "  # validation should pass or fail.",
-        "  ctx.actions.run(",
-        "      outputs = [validation_output],",
-        "      executable = ctx.executable._validation_tool,",
-        "      arguments = [validation_output.path])",
-        "",
-        "  return [",
-        "    DefaultInfo(files = depset([ctx.outputs.main])),",
-        "    OutputGroupInfo(_validation = depset([validation_output])),",
-        "  ]",
-        "",
-        "",
-        "rule_with_implicit_outs_and_validation = rule(",
-        "  implementation = _rule_with_implicit_outs_and_validation_impl,",
-        "  outputs = {",
-        "    \"main\": \"%{name}.main\",",
-        "    \"implicit\": \"%{name}.implicit\",",
-        "  },",
-        "  attrs = {",
-        "    \"_validation_tool\": attr.label(",
-        "        allow_single_file = True,",
-        "        default = Label(\"//validation_actions:validation_tool\"),",
-        "        executable = True,",
-        "        cfg = \"host\"),",
-        "  }",
-        ")");
-    write("validation_actions/validation_tool", "#!/bin/bash", "echo \"validation output\" > $1")
-        .setExecutable(true);
-    write(
-        "validation_actions/BUILD",
-        "load(",
-        "    \":defs.bzl\",",
-        "    \"rule_with_implicit_outs_and_validation\")",
-        "",
-        "rule_with_implicit_outs_and_validation(name = \"foo0\")");
-
-    AtomicReference<TargetCompleteEvent> targetCompleteEventRef = new AtomicReference<>();
-    runtimeWrapper.registerSubscriber(
-        new Object() {
-          @SuppressWarnings("unused")
-          @Subscribe
-          public void accept(TargetCompleteEvent event) {
-            targetCompleteEventRef.set(event);
-          }
-        });
-
-    addOptions("--experimental_run_validations");
-    BuildResult buildResult = buildTarget("//validation_actions:foo0");
-
-    Collection<ConfiguredTarget> successfulTargets = buildResult.getSuccessfulTargets();
-    ConfiguredTarget fooTarget = Iterables.getOnlyElement(successfulTargets);
-
-    // Check that the primary output, :foo0.main, has its metadata retained and the
-    // CompletionContext can confirm it is an output file.
-    Artifact main =
-        ((RuleConfiguredTarget) fooTarget)
-            .getArtifactByOutputLabel(
-                Label.parseAbsoluteUnchecked("//validation_actions:foo0.main"));
-    assertThat(targetCompleteEventRef.get().getCompletionContext().isGuaranteedToBeOutputFile(main))
-        .isTrue();
-
-    // Check that the validation output, :foo0.validation, does not have its metadata retained and
-    // the CompletionContext cannot confirm it is an output file (even though it is).
-    OutputGroupInfo outputGroups = fooTarget.get(OutputGroupInfo.STARLARK_CONSTRUCTOR);
-    NestedSet<Artifact> validationArtifacts =
-        outputGroups.getOutputGroup(OutputGroupInfo.VALIDATION);
-    assertThat(validationArtifacts.isEmpty()).isFalse();
-
-    Artifact validationArtifact = Iterables.getOnlyElement(validationArtifacts.toList());
-
-    assertThat(targetCompleteEventRef.get()).isNotNull();
-    assertThat(
-            targetCompleteEventRef
-                .get()
-                .getCompletionContext()
-                .isGuaranteedToBeOutputFile(validationArtifact))
-        .isFalse();
-  }
-}
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventTest.java
new file mode 100644
index 0000000..e8af081
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventTest.java
@@ -0,0 +1,234 @@
+// Copyright 2021 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.buildtool;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.Iterables;
+import com.google.common.eventbus.Subscribe;
+import com.google.common.hash.HashCode;
+import com.google.common.io.BaseEncoding;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.CompletionContext;
+import com.google.devtools.build.lib.actions.FileArtifactValue;
+import com.google.devtools.build.lib.actions.FileStateType;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.OutputGroupInfo;
+import com.google.devtools.build.lib.analysis.TargetCompleteEvent;
+import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
+import com.google.devtools.build.lib.analysis.util.AnalysisMock;
+import com.google.devtools.build.lib.buildeventservice.BazelBuildEventServiceModule;
+import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos;
+import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEvent;
+import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEventId.IdCase;
+import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.NamedSetOfFiles;
+import com.google.devtools.build.lib.buildtool.util.BuildIntegrationTestCase;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+import com.google.devtools.build.lib.packages.util.MockGenruleSupport;
+import com.google.devtools.build.lib.runtime.BlazeRuntime;
+import com.google.devtools.build.lib.runtime.NoSpawnCacheModule;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+import javax.annotation.Nullable;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Verifies TargetCompleteEvent behavior during a complete build. */
+@RunWith(JUnit4.class)
+public final class TargetCompleteEventTest extends BuildIntegrationTestCase {
+
+  @Rule public final TemporaryFolder tmpFolder = new TemporaryFolder();
+
+  @Before
+  public void stageEmbeddedTools() throws Exception {
+    AnalysisMock.get().setupMockToolsRepository(mockToolsConfig);
+  }
+
+  @Override
+  protected BlazeRuntime.Builder getRuntimeBuilder() throws Exception {
+    return super.getRuntimeBuilder()
+        .addBlazeModule(new NoSpawnCacheModule())
+        .addBlazeModule(new BazelBuildEventServiceModule());
+  }
+
+  private void afterBuildCommand() throws Exception {
+    runtimeWrapper.newCommand();
+  }
+
+  /**
+   * Validates that TargetCompleteEvents do not keep a map of action output metadata for the
+   * _validation output group, which can be quite large.
+   */
+  @Test
+  public void artifactsNotRetained() throws Exception {
+    write(
+        "validation_actions/defs.bzl",
+        "def _rule_with_implicit_outs_and_validation_impl(ctx):",
+        "",
+        "  ctx.actions.write(ctx.outputs.main, \"main output\\n\")",
+        "",
+        "  ctx.actions.write(ctx.outputs.implicit, \"implicit output\\n\")",
+        "",
+        "  validation_output = ctx.actions.declare_file(ctx.attr.name + \".validation\")",
+        "  # The actual tool will be created in individual tests, depending on whether",
+        "  # validation should pass or fail.",
+        "  ctx.actions.run(",
+        "      outputs = [validation_output],",
+        "      executable = ctx.executable._validation_tool,",
+        "      arguments = [validation_output.path])",
+        "",
+        "  return [",
+        "    DefaultInfo(files = depset([ctx.outputs.main])),",
+        "    OutputGroupInfo(_validation = depset([validation_output])),",
+        "  ]",
+        "",
+        "",
+        "rule_with_implicit_outs_and_validation = rule(",
+        "  implementation = _rule_with_implicit_outs_and_validation_impl,",
+        "  outputs = {",
+        "    \"main\": \"%{name}.main\",",
+        "    \"implicit\": \"%{name}.implicit\",",
+        "  },",
+        "  attrs = {",
+        "    \"_validation_tool\": attr.label(",
+        "        allow_single_file = True,",
+        "        default = Label(\"//validation_actions:validation_tool\"),",
+        "        executable = True,",
+        "        cfg = \"host\"),",
+        "  }",
+        ")");
+    write("validation_actions/validation_tool", "#!/bin/bash", "echo \"validation output\" > $1")
+        .setExecutable(true);
+    write(
+        "validation_actions/BUILD",
+        "load(",
+        "    \":defs.bzl\",",
+        "    \"rule_with_implicit_outs_and_validation\")",
+        "",
+        "rule_with_implicit_outs_and_validation(name = \"foo0\")");
+
+    AtomicReference<TargetCompleteEvent> targetCompleteEventRef = new AtomicReference<>();
+    runtimeWrapper.registerSubscriber(
+        new Object() {
+          @SuppressWarnings("unused")
+          @Subscribe
+          public void accept(TargetCompleteEvent event) {
+            targetCompleteEventRef.set(event);
+          }
+        });
+
+    addOptions("--experimental_run_validations");
+    BuildResult buildResult = buildTarget("//validation_actions:foo0");
+
+    Collection<ConfiguredTarget> successfulTargets = buildResult.getSuccessfulTargets();
+    ConfiguredTarget fooTarget = Iterables.getOnlyElement(successfulTargets);
+
+    // Check that the primary output, :foo0.main, has its metadata retained and the
+    // CompletionContext can confirm it is an output file.
+    Artifact main =
+        ((RuleConfiguredTarget) fooTarget)
+            .getArtifactByOutputLabel(
+                Label.parseAbsoluteUnchecked("//validation_actions:foo0.main"));
+    FileStateType mainType =
+        targetCompleteEventRef.get().getCompletionContext().getFileArtifactValue(main).getType();
+    assertThat(CompletionContext.isGuaranteedToBeOutputFile(mainType)).isTrue();
+
+    // Check that the validation output, :foo0.validation, does not have its metadata retained and
+    // the CompletionContext cannot confirm it is an output file (even though it is).
+    OutputGroupInfo outputGroups = fooTarget.get(OutputGroupInfo.STARLARK_CONSTRUCTOR);
+    NestedSet<Artifact> validationArtifacts =
+        outputGroups.getOutputGroup(OutputGroupInfo.VALIDATION);
+    assertThat(validationArtifacts.isEmpty()).isFalse();
+
+    Artifact validationArtifact = Iterables.getOnlyElement(validationArtifacts.toList());
+
+    FileArtifactValue validationArtifactMetadata =
+        targetCompleteEventRef
+            .get()
+            .getCompletionContext()
+            .getFileArtifactValue(validationArtifact);
+    assertThat(validationArtifactMetadata).isNull();
+  }
+
+  @Test
+  public void digestAndLengthInBuildEventProtocol() throws Exception {
+    MockGenruleSupport.setup(mockToolsConfig);
+
+    // Produces a TargetCompleteEvent in BEP and verifies that we include the output file's
+    // length and digest.
+    write(
+        "foo/BUILD",
+        "genrule(name = 'foobin', outs = ['out.txt'], cmd = 'echo -n \"Hello\" > $@')");
+    File buildEventBinaryFile = tmpFolder.newFile();
+    // We use WAIT_FOR_UPLOAD_COMPLETE because it's the easiest way to force the BES module to
+    // wait until the BEP binary file has been written.
+    addOptions(
+        "--build_event_binary_file=" + buildEventBinaryFile.getAbsolutePath(),
+        "--bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE");
+    buildTarget("//foo:foobin");
+    // We need to wait for all events to be written to the file, which is done in #afterCommand()
+    // if --bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE.
+    afterBuildCommand();
+
+    List<BuildEvent> buildEvents = new ArrayList<>();
+    try (InputStream in = new FileInputStream(buildEventBinaryFile)) {
+      while (in.available() > 0) {
+        buildEvents.add(BuildEvent.parseDelimitedFrom(in));
+      }
+    }
+    BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(buildEvents);
+    assertThat(outFile).isNotNull();
+    assertThat(outFile.getLength()).isEqualTo("Hello".length());
+    byte[] bepDigest = BaseEncoding.base16().lowerCase().decode(outFile.getDigest());
+    // Try all registered hash functions and verify that one of them was used to produce the digest.
+    boolean foundHashFunction = false;
+    for (DigestHashFunction hashFunction : DigestHashFunction.getPossibleHashFunctions()) {
+      HashCode hashCode =
+          hashFunction.getHashFunction().hashString("Hello", StandardCharsets.UTF_8);
+      if (Arrays.equals(bepDigest, hashCode.asBytes())) {
+        foundHashFunction = true;
+      }
+    }
+    assertThat(foundHashFunction).isTrue();
+  }
+
+  @Nullable
+  private static BuildEventStreamProtos.File findOutputFileInBEPStream(
+      List<BuildEvent> buildEvents) {
+    for (BuildEvent buildEvent : buildEvents) {
+      if (buildEvent.getId().getIdCase() == IdCase.NAMED_SET) {
+        NamedSetOfFiles namedSetOfFiles = buildEvent.getNamedSetOfFiles();
+        for (BuildEventStreamProtos.File file : namedSetOfFiles.getFilesList()) {
+          if (file.getName().contains("out.txt")) {
+            return file;
+          }
+        }
+      }
+    }
+    return null;
+  }
+}