Allow SkyValues to be marked not "comparable". Such values are not compared for the purpose of change pruning.

--
MOS_MIGRATED_REVID=108203369

3 files changed, 81 insertions, 3 deletions

diff --git a/src/test/java/com/google/devtools/build/skyframe/GraphTester.java b/src/test/java/com/google/devtools/build/skyframe/GraphTester.java
index 2d44e9ddc5..2a3fc1b4af 100644
--- a/src/test/java/com/google/devtools/build/skyframe/GraphTester.java
+++ b/src/test/java/com/google/devtools/build/skyframe/GraphTester.java
@@ -291,7 +291,7 @@ public class GraphTester {
    * Simple value class that stores strings.
    */
   public static class StringValue implements SkyValue {
-    private final String value;
+    protected final String value;
 
     public StringValue(String value) {
       this.value = value;
@@ -329,6 +329,24 @@ public class GraphTester {
     }
   }
 
+  /** A StringValue that is also a NotComparableSkyValue. */
+  public static class NotComparableStringValue extends StringValue
+          implements NotComparableSkyValue {
+    public NotComparableStringValue(String value) {
+      super(value);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      throw new UnsupportedOperationException(value + " is incomparable - what are you doing?");
+    }
+
+    @Override
+    public int hashCode() {
+      throw new UnsupportedOperationException(value + " is incomparable - what are you doing?");
+    }
+  }
+
   /**
    * A callback interface to provide the value computation.
    */
diff --git a/src/test/java/com/google/devtools/build/skyframe/InMemoryNodeEntryTest.java b/src/test/java/com/google/devtools/build/skyframe/InMemoryNodeEntryTest.java
index 8b7c0d2c8c..0304513344 100644
--- a/src/test/java/com/google/devtools/build/skyframe/InMemoryNodeEntryTest.java
+++ b/src/test/java/com/google/devtools/build/skyframe/InMemoryNodeEntryTest.java
@@ -492,7 +492,7 @@ public class InMemoryNodeEntryTest {
   }
 
   @Test
-  public void pruneErrorValue() {
+  public void errorInfoCannotBePruned() {
     NodeEntry entry = new InMemoryNodeEntry();
     entry.addReverseDepAndCheckIfDone(null); // Start evaluation.
     SkyKey dep = key("dep");
@@ -514,7 +514,8 @@ public class InMemoryNodeEntryTest {
     assertThat(entry.markRebuildingAndGetAllRemainingDirtyDirectDeps()).isEmpty();
     setValue(entry, /*value=*/null, errorInfo, /*graphVersion=*/1L);
     assertTrue(entry.isDone());
-    assertEquals(new IntVersion(0L), entry.getVersion());
+    // ErrorInfo is treated as a NotComparableSkyValue, so it is not pruned.
+    assertEquals(new IntVersion(1L), entry.getVersion());
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java b/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
index fdae6b25c0..a24e93cff1 100644
--- a/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
+++ b/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
@@ -45,12 +45,14 @@ import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.events.EventKind;
 import com.google.devtools.build.lib.testutil.TestThread;
 import com.google.devtools.build.lib.testutil.TestUtils;
+import com.google.devtools.build.skyframe.GraphTester.NotComparableStringValue;
 import com.google.devtools.build.skyframe.GraphTester.StringValue;
 import com.google.devtools.build.skyframe.GraphTester.TestFunction;
 import com.google.devtools.build.skyframe.GraphTester.ValueComputer;
 import com.google.devtools.build.skyframe.NotifyingInMemoryGraph.EventType;
 import com.google.devtools.build.skyframe.NotifyingInMemoryGraph.Listener;
 import com.google.devtools.build.skyframe.NotifyingInMemoryGraph.Order;
+import com.google.devtools.build.skyframe.SkyFunction.Environment;
 import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
 
 import org.junit.After;
@@ -3113,6 +3115,63 @@ public class MemoizingEvaluatorTest {
   }
 
   @Test
+  public void notComparableNotPrunedNoEvent() throws Exception {
+    checkNotComparableNotPruned(false);
+  }
+
+  @Test
+  public void notComparableNotPrunedEvent() throws Exception {
+    checkNotComparableNotPruned(true);
+  }
+
+  private void checkNotComparableNotPruned(boolean hasEvent) throws Exception {
+    initializeTester();
+    SkyKey parent = GraphTester.toSkyKey("parent");
+    SkyKey child = GraphTester.toSkyKey("child");
+    NotComparableStringValue notComparableString = new NotComparableStringValue("not comparable");
+    if (hasEvent) {
+      tester.getOrCreate(child).setConstantValue(notComparableString).setWarning("shmoop");
+    } else {
+      tester.getOrCreate(child).setConstantValue(notComparableString);
+    }
+    final AtomicInteger parentEvaluated = new AtomicInteger();
+    final String val = "some val";
+    tester
+        .getOrCreate(parent)
+        .addDependency(child)
+        .setComputedValue(new ValueComputer() {
+          @Override
+          public SkyValue compute(Map<SkyKey, SkyValue> deps, Environment env)
+              throws InterruptedException {
+            parentEvaluated.incrementAndGet();
+            return new StringValue(val);
+          }
+        });
+    assertStringValue(val, tester.evalAndGet( /*keepGoing=*/false, parent));
+    assertThat(parentEvaluated.get()).isEqualTo(1);
+    if (hasEvent) {
+      assertContainsEvent(eventCollector, "shmoop");
+    } else {
+      assertEventCount(0, eventCollector);
+    }
+
+    tester.resetPlayedEvents();
+    tester.getOrCreate(child, /*markAsModified=*/true);
+    tester.invalidate();
+    assertStringValue(val, tester.evalAndGet( /*keepGoing=*/false, parent));
+    assertThat(parentEvaluated.get()).isEqualTo(2);
+    if (hasEvent) {
+      assertContainsEvent(eventCollector, "shmoop");
+    } else {
+      assertEventCount(0, eventCollector);
+    }
+  }
+
+  private static void assertStringValue(String expected, SkyValue val) {
+    assertThat(((StringValue) val).getValue()).isEqualTo(expected);
+  }
+
+  @Test
   public void changePruningWithEvent() throws Exception {
     initializeTester();
     SkyKey parent = GraphTester.toSkyKey("parent");