From 51da0631c0b688c63da3e43e76d20181d4ec6f0e Mon Sep 17 00:00:00 2001
From: Michael McCandless <mikemccand@apache.org>
Date: Thu, 15 Aug 2013 22:42:54 +0000
Subject: [PATCH] LUCENE-5152: make assert less costly

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1514520 13f79535-47bb-0310-9956-ffa450edef68
---
 lucene/core/src/java/org/apache/lucene/util/fst/FST.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
index 2f1df2758af..4afaa9a72ff 100644
--- a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
+++ b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
@@ -1140,7 +1140,6 @@ public final class FST<T> {
   /** Finds an arc leaving the incoming arc, replacing the arc in place.
    *  This returns null if the arc was not found, else the incoming arc. */
   public Arc<T> findTargetArc(int labelToMatch, Arc<T> follow, Arc<T> arc, BytesReader in) throws IOException {
-    assert assertRootArcs();
 
     if (labelToMatch == END_LABEL) {
       if (follow.isFinal()) {
@@ -1162,6 +1161,10 @@ public final class FST<T> {
 
     // Short-circuit if this arc is in the root arc cache:
     if (follow.target == startNode && labelToMatch < cachedRootArcs.length) {
+      
+      // LUCENE-5152: detect tricky cases where caller
+      // modified previously returned cached root-arcs:
+      assert assertRootArcs();
       final Arc<T> result = cachedRootArcs[labelToMatch];
       if (result == null) {
         return null;