Order tree artifacts.

Fixes #5686.

RELNOTES: None
PiperOrigin-RevId: 207559658

2 files changed, 36 insertions, 13 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
index 13ff08a65f..aca26775a1 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
@@ -13,13 +13,12 @@
 // limitations under the License.
 package com.google.devtools.build.lib.skyframe;
 
-import com.google.common.base.Function;
 import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Maps;
-import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
 import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.actions.cache.DigestUtils;
@@ -29,6 +28,7 @@ import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.skyframe.SkyValue;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.Map;
 import java.util.Set;
 import javax.annotation.Nullable;
@@ -39,21 +39,14 @@ import javax.annotation.Nullable;
  */
 @AutoCodec
 class TreeArtifactValue implements SkyValue {
-  private static final Function<Artifact, PathFragment> PARENT_RELATIVE_PATHS =
-      new Function<Artifact, PathFragment>() {
-        @Override
-        public PathFragment apply(Artifact artifact) {
-            return artifact.getParentRelativePath();
-        }
-      };
 
   private final byte[] digest;
-  private final Map<TreeFileArtifact, FileArtifactValue> childData;
+  private final ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> childData;
 
   @AutoCodec.VisibleForSerialization
   TreeArtifactValue(byte[] digest, Map<TreeFileArtifact, FileArtifactValue> childData) {
     this.digest = digest;
-    this.childData = ImmutableMap.copyOf(childData);
+    this.childData = sortedCopy(childData);
   }
 
   /**
@@ -69,7 +62,13 @@ class TreeArtifactValue implements SkyValue {
 
     return new TreeArtifactValue(
         DigestUtils.fromMetadata(digestBuilder).getDigestBytesUnsafe(),
-        ImmutableMap.copyOf(childFileValues));
+        sortedCopy(childFileValues));
+  }
+
+  private static ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> sortedCopy(
+      Map<TreeFileArtifact, FileArtifactValue> data) {
+    return ImmutableSortedMap.copyOf(data,
+        Comparator.comparing(TreeFileArtifact::getParentRelativePath));
   }
 
   FileArtifactValue getSelfData() {
@@ -81,7 +80,8 @@ class TreeArtifactValue implements SkyValue {
   }
 
   Set<PathFragment> getChildPaths() {
-    return ImmutableSet.copyOf(Iterables.transform(childData.keySet(), PARENT_RELATIVE_PATHS));
+    return ImmutableSet.copyOf(Iterables.transform(childData.keySet(),
+        TreeFileArtifact::getParentRelativePath));
   }
 
   @Nullable
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactMetadataTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactMetadataTest.java
index 0f5d21bca7..15e7b82168 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactMetadataTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactMetadataTest.java
@@ -55,9 +55,14 @@ import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Random;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -124,6 +129,24 @@ public class TreeArtifactMetadataTest extends ArtifactFunctionTestCase {
   }
 
   @Test
+  public void testTreeArtifactOrdering() throws Exception {
+    int rangeSize = 100;
+    int attempts = 10;
+    List<PathFragment> children =
+        IntStream.range(0, rangeSize)
+            .mapToObj(i -> PathFragment.create("file" + i))
+            .collect(Collectors.toList());
+
+    for (int i = 0; i < attempts; i++) {
+      Collections.shuffle(children, new Random());
+      Artifact treeArtifact = createTreeArtifact("out");
+      TreeArtifactValue value = evaluateTreeArtifact(treeArtifact, children);
+      assertThat(value.getChildPaths()).containsExactlyElementsIn(children);
+      assertThat(value.getChildPaths()).isOrdered(Comparator.naturalOrder());
+    }
+  }
+
+  @Test
   public void testEqualTreeArtifacts() throws Exception {
     Artifact treeArtifact = createTreeArtifact("out");
     ImmutableList<PathFragment> children =