1 files changed, 11 insertions, 1 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/util/GroupedList.java b/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
index 475e38518b..11bef3fcc2 100644
--- a/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
+++ b/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
@@ -343,6 +343,9 @@ public class GroupedList<T> implements Iterable<Collection<T>> {
    * GroupedListHelper.
    */
   private static <E> List<Object> remove(List<Object> elements, Set<E> toRemove) {
+    if (toRemove.isEmpty()) {
+      return elements;
+    }
     int removedCount = 0;
     // elements.size is an upper bound of the needed size. Since normally removal happens just
     // before the list is finished and compressed, optimizing this size isn't a concern.
@@ -369,8 +372,15 @@ public class GroupedList<T> implements Iterable<Collection<T>> {
         }
       }
     }
+    // removedCount can be larger if elements had duplicates and the duplicate was also in toRemove.
     Preconditions.checkState(
-        removedCount == toRemove.size(), "%s %s %s", elements, toRemove, newElements);
+        removedCount >= toRemove.size(),
+        "removedCount=%s, toRemove.size()=%s, elements=%s toRemove=%s newElements=%s",
+        removedCount,
+        toRemove.size(),
+        elements,
+        toRemove,
+        newElements);
     return newElements;
   }