diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BUILD b/src/main/java/com/google/devtools/build/lib/analysis/BUILD
index 208da8fe11db81..64993b41dd59e5 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BUILD
@@ -1699,6 +1699,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec:serialization-constant",
         "//src/main/java/com/google/devtools/build/lib/util",
         "//src/main/java/com/google/devtools/common/options",
+        "//third_party:error_prone_annotations",
         "//third_party:guava",
         "//third_party:jsr305",
         "//third_party/protobuf:protobuf_java",
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
index ba866b34e7fdd2..08065c4457bb31 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.collect.ImmutableMap.toImmutableMap;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.MoreObjects;
@@ -230,14 +231,16 @@ public ImmutableMap<Label, Object> getStarlarkOptions() {
    */
   @Override
   public BuildOptions clone() {
-    ImmutableMap.Builder<Class<? extends FragmentOptions>, FragmentOptions> nativeOptionsBuilder =
-        ImmutableMap.builderWithExpectedSize(fragmentOptionsMap.size());
-    for (Map.Entry<Class<? extends FragmentOptions>, FragmentOptions> entry :
-        fragmentOptionsMap.entrySet()) {
-      nativeOptionsBuilder.put(entry.getKey(), entry.getValue().clone());
-    }
-    return new BuildOptions(
-        nativeOptionsBuilder.buildOrThrow(), ImmutableMap.copyOf(starlarkOptionsMap));
+    ImmutableMap<Class<? extends FragmentOptions>, FragmentOptions> nativeOptions =
+        fragmentOptionsMap.entrySet().stream()
+            .collect(
+                toImmutableMap(
+                    Map.Entry::getKey,
+                    // Explicitly clone native options because FragmentOptions is mutable.
+                    e -> e.getValue().clone()));
+    // Note that this assumes that starlark option values are immutable.
+    ImmutableMap<Label, Object> starlarkOptions = ImmutableMap.copyOf(starlarkOptionsMap);
+    return new BuildOptions(nativeOptions, starlarkOptions);
   }
 
   @Override