1 files changed, 8 insertions, 1 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/actions/MutableActionGraph.java b/src/main/java/com/google/devtools/build/lib/actions/MutableActionGraph.java
index 637442dd4c..6eae2a3b67 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/MutableActionGraph.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/MutableActionGraph.java
@@ -143,6 +143,12 @@ public interface MutableActionGraph extends ActionGraph {
       }
     }
 
+    private static String getKey(ActionAnalysisMetadata action) {
+      return action instanceof Action
+          ? ((Action) action).getKey()
+          : null;
+    }
+
     // See also Actions.canBeShared()
     private static String suffix(ActionAnalysisMetadata a, ActionAnalysisMetadata b) {
       // Note: the error message reveals to users the names of intermediate files that are not
@@ -161,6 +167,7 @@ public interface MutableActionGraph extends ActionGraph {
       addStringDetail(sb, "Configuration", aNull ? null : aOwner.getConfigurationChecksum(),
           bNull ? null : bOwner.getConfigurationChecksum());
       addStringDetail(sb, "Mnemonic", a.getMnemonic(), b.getMnemonic());
+      addStringDetail(sb, "Action key", getKey(a), getKey(b));
 
       if ((a instanceof ActionExecutionMetadata) && (b instanceof ActionExecutionMetadata)) {
         addStringDetail(
@@ -187,7 +194,7 @@ public interface MutableActionGraph extends ActionGraph {
               && bPrimaryInput != null
               && aPrimaryInput.toString().equals(bPrimaryInput.toString()))) {
         if (aPrimaryInput != bPrimaryInput) {
-          sb.append("Primary outputs are different objects: ")
+          sb.append("Primary inputs are different objects: ")
               .append(System.identityHashCode(aPrimaryInput))
               .append(", ")
               .append(System.identityHashCode(bPrimaryInput))