Allow NestedSetCodec to share members across multiple deserializations.

This avoids redundancy in memory when multiple NestedSets share a member

PiperOrigin-RevId: 190085907

1 files changed, 25 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/collect/nestedset/NestedSetCodecTest.java b/src/test/java/com/google/devtools/build/lib/collect/nestedset/NestedSetCodecTest.java
index 978d7a0bb5..74eea2176d 100644
--- a/src/test/java/com/google/devtools/build/lib/collect/nestedset/NestedSetCodecTest.java
+++ b/src/test/java/com/google/devtools/build/lib/collect/nestedset/NestedSetCodecTest.java
@@ -15,8 +15,12 @@ package com.google.devtools.build.lib.collect.nestedset;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.skyframe.serialization.AutoRegistry;
+import com.google.devtools.build.lib.skyframe.serialization.ObjectCodecs;
 import com.google.devtools.build.lib.skyframe.serialization.SerializationConstants;
 import com.google.devtools.build.lib.skyframe.serialization.testutils.SerializationTester;
+import com.google.protobuf.ByteString;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -66,6 +70,27 @@ public class NestedSetCodecTest {
         .runTests();
   }
 
+  @SuppressWarnings("unchecked")
+  @Test
+  public void testDeserializedNestedSetsShareChildren() throws Exception {
+    ObjectCodecs objectCodecs =
+        new ObjectCodecs(
+            AutoRegistry.get().getBuilder().setAllowDefaultCodec(true).build(), ImmutableMap.of());
+    NestedSet<String> originalChild = NestedSetBuilder.create(Order.STABLE_ORDER, "a", "b", "c");
+    NestedSet<String> originalA =
+        new NestedSetBuilder<String>(Order.STABLE_ORDER).addTransitive(originalChild).build();
+    NestedSet<String> originalB =
+        new NestedSetBuilder<String>(Order.STABLE_ORDER).addTransitive(originalChild).build();
+
+    ByteString serializedA = objectCodecs.serialize(originalA);
+    ByteString serializedB = objectCodecs.serialize(originalB);
+
+    NestedSet<String> deserializedA = (NestedSet<String>) objectCodecs.deserialize(serializedA);
+    NestedSet<String> deserializedB = (NestedSet<String>) objectCodecs.deserialize(serializedB);
+
+    assertThat(deserializedA.rawChildren()).isSameAs(deserializedB.rawChildren());
+  }
+
   private static void verifyDeserialization(
       NestedSet<String> subject, NestedSet<String> deserialized) {
     assertThat(subject.getOrder()).isEqualTo(deserialized.getOrder());