Preload transitive closure for somepath in GraphlessBlazeQueryEnvironment.

We already did this for the traditional query. Not preloading means that we
load each package in their own ParallelEvaluator.call which is slow.

RELNOTES: None
PiperOrigin-RevId: 280158680
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/SomePathFunction.java b/src/main/java/com/google/devtools/build/lib/query2/engine/SomePathFunction.java
index 232ae61..a08b098 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/engine/SomePathFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/engine/SomePathFunction.java
@@ -24,7 +24,6 @@
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskCallable;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskFuture;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ThreadSafeMutableSet;
-import java.util.Collection;
 import java.util.List;
 
 /**
@@ -70,8 +69,11 @@
           new QueryTaskCallable<Void>() {
             @Override
             public Void call() throws QueryException, InterruptedException {
-              Collection<T> fromValue = fromValueFuture.getIfSuccessful();
-              Collection<T> toValue = toValueFuture.getIfSuccessful();
+              ThreadSafeMutableSet<T> fromValue = fromValueFuture.getIfSuccessful();
+              ThreadSafeMutableSet<T> toValue = toValueFuture.getIfSuccessful();
+
+              env.buildTransitiveClosure(expression, fromValue, Integer.MAX_VALUE);
+
               ((CustomFunctionQueryEnvironment<T>) env)
                   .somePath(fromValue, toValue, expression, callback);
               return null;
diff --git a/src/main/java/com/google/devtools/build/lib/query2/query/GraphlessBlazeQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/query/GraphlessBlazeQueryEnvironment.java
index 8f270e4..c381098 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/query/GraphlessBlazeQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/query/GraphlessBlazeQueryEnvironment.java
@@ -298,7 +298,6 @@
     if (errorObserver.hasErrors()) {
       reportBuildFileError(caller, "errors were encountered while computing transitive closure");
     }
-    throw new UnsupportedOperationException();
   }
 
   @Override