Adds an enum to describe how PackageLookupFunction should handle package labels
which cross into a sub-repository. Part of #1592.

--
MOS_MIGRATED_REVID=135931868
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java
index 7841f36..4bbad97 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java
@@ -35,6 +35,7 @@
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.events.NullEventHandler;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
+import com.google.devtools.build.lib.skyframe.PackageLookupFunction.CrossRepositoryLabelViolationStrategy;
 import com.google.devtools.build.lib.skyframe.RecursiveFilesystemTraversalValue.ResolvedFile;
 import com.google.devtools.build.lib.skyframe.RecursiveFilesystemTraversalValue.TraversalRequest;
 import com.google.devtools.build.lib.testutil.FoundationTestCase;
@@ -54,12 +55,6 @@
 import com.google.devtools.build.skyframe.SkyFunctionName;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
@@ -69,6 +64,10 @@
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.regex.Pattern;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
 
 /** Tests for {@link RecursiveFilesystemTraversalFunction}. */
 @RunWith(JUnit4.class)
@@ -103,13 +102,13 @@
         new DirectoryListingStateFunction(externalFilesHelper));
     skyFunctions.put(
         SkyFunctions.RECURSIVE_FILESYSTEM_TRAVERSAL, new RecursiveFilesystemTraversalFunction());
-    skyFunctions.put(SkyFunctions.PACKAGE_LOOKUP, new PackageLookupFunction(deletedPackages));
+    skyFunctions.put(
+        SkyFunctions.PACKAGE_LOOKUP,
+        new PackageLookupFunction(deletedPackages, CrossRepositoryLabelViolationStrategy.ERROR));
     skyFunctions.put(SkyFunctions.BLACKLISTED_PACKAGE_PREFIXES,
         new BlacklistedPackagePrefixesFunction());
     skyFunctions.put(SkyFunctions.PACKAGE,
         new PackageFunction(null, null, null, null, null, null, null));
-    skyFunctions.put(SkyFunctions.PACKAGE_LOOKUP,
-        new PackageLookupFunction(deletedPackages));
     skyFunctions.put(SkyFunctions.WORKSPACE_AST, new WorkspaceASTFunction(ruleClassProvider));
     skyFunctions.put(
         SkyFunctions.WORKSPACE_FILE,