1 files changed, 9 insertions, 3 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
index 9290fc79a2..a1f82a9785 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
@@ -52,6 +52,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+
 /**
  * Action used by extra_action rules to create an action that shadows an existing action. Runs a
  * command-line using {@link SpawnActionContext} for executions.
@@ -115,8 +117,9 @@ public final class ExtraAction extends SpawnAction {
     return shadowedAction.discoversInputs();
   }
 
+  @Nullable
   @Override
-  public void discoverInputs(ActionExecutionContext actionExecutionContext)
+  public Collection<Artifact> discoverInputs(ActionExecutionContext actionExecutionContext)
       throws ActionExecutionException, InterruptedException {
     Preconditions.checkState(discoversInputs(), this);
     if (getContext(actionExecutionContext.getExecutor()).isRemotable(getMnemonic(),
@@ -124,10 +127,13 @@ public final class ExtraAction extends SpawnAction {
       // If we're running remotely, we need to update our inputs to take account of any additional
       // inputs the shadowed action may need to do its work.
       if (shadowedAction.discoversInputs() && shadowedAction instanceof AbstractAction) {
-        updateInputs(
-            ((AbstractAction) shadowedAction).getInputFilesForExtraAction(actionExecutionContext));
+        Iterable<Artifact> additionalInputs =
+            ((AbstractAction) shadowedAction).getInputFilesForExtraAction(actionExecutionContext);
+        updateInputs(additionalInputs);
+        return ImmutableSet.copyOf(additionalInputs);
       }
     }
+    return null;
   }
 
   @Override