Description redacted.

--
MOS_MIGRATED_REVID=86685664

src/main/java/com/google/devtools/build/lib/analysis/PrerequisiteArtifacts.java

@@ -20,6 +20,8 @@
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.util.FileType;
 import com.google.devtools.build.lib.util.FileTypeSet;
 
@@ -51,6 +53,16 @@ static PrerequisiteArtifacts get(RuleContext ruleContext, String attributeName,
     return new PrerequisiteArtifacts(ruleContext, attributeName, ImmutableList.copyOf(result));
   }
 
+  public static NestedSet<Artifact> nestedSet(RuleContext ruleContext, String attributeName,
+      Mode mode) {
+    NestedSetBuilder<Artifact> result = NestedSetBuilder.stableOrder();
+    for (FileProvider target :
+        ruleContext.getPrerequisites(attributeName, mode, FileProvider.class)) {
+      result.addTransitive(target.getFilesToBuild());
+    }
+    return result.build();
+  }
+
   /**
    * Returns the artifacts this instance contains in an {@link ImmutableList}.
    */