From 6bf4d35ce81248164ec2f478212e967fb8c2a69a Mon Sep 17 00:00:00 2001
From: Mark Robert Miller <markrmiller@apache.org>
Date: Tue, 14 Jul 2009 20:56:50 +0000
Subject: [PATCH] LUCENE-1583: SpanOrQuery skipTo() doesn't always move
 forwards as Spans documentation indicates it should.

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@794063 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                     |  3 +++
 .../apache/lucene/search/spans/SpanOrQuery.java | 11 ++++++++---
 .../apache/lucene/search/spans/TestSpans.java   | 17 +++++++++++++++++
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 9df6dcbbb26..378ebd059f7 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -378,6 +378,9 @@ Bug fixes
 
 18. LUCENE-1718: Fix termInfosIndexDivisor to carry over to reopened
     readers (Mike McCandless)
+    
+19. LUCENE-1583: SpanOrQuery skipTo() doesn't always move forwards as Spans
+	documentation indicates it should.  (Moti Nisenson via Mark Miller)
 
 New features
 
diff --git a/src/java/org/apache/lucene/search/spans/SpanOrQuery.java b/src/java/org/apache/lucene/search/spans/SpanOrQuery.java
index 1af3a9dbe4c..2171f59c7b0 100644
--- a/src/java/org/apache/lucene/search/spans/SpanOrQuery.java
+++ b/src/java/org/apache/lucene/search/spans/SpanOrQuery.java
@@ -215,16 +215,21 @@ public class SpanOrQuery extends SpanQuery implements Cloneable {
           if (queue == null) {
             return initSpanQueue(target);
           }
-
+  
+          boolean skipCalled = false;
           while (queue.size() != 0 && top().doc() < target) {
             if (top().skipTo(target)) {
               queue.adjustTop();
             } else {
               queue.pop();
             }
+            skipCalled = true;
           }
-
-          return queue.size() != 0;
+  
+          if (skipCalled) {
+            return queue.size() != 0;
+          }
+          return next();
         }
 
         public int doc() { return top().doc(); }
diff --git a/src/test/org/apache/lucene/search/spans/TestSpans.java b/src/test/org/apache/lucene/search/spans/TestSpans.java
index 66268934070..a7d4da7c9e7 100644
--- a/src/test/org/apache/lucene/search/spans/TestSpans.java
+++ b/src/test/org/apache/lucene/search/spans/TestSpans.java
@@ -331,6 +331,23 @@ public class TestSpans extends LuceneTestCase {
     assertFalse("final next", spans.next());
   }
   
+  public void testSpanOrMovesForward() throws Exception {
+    Spans spans = orSpans(new String[] {"w1", "xx"});
+
+    spans.next();
+    int doc = spans.doc();
+    assertEquals(0, doc);
+    
+    spans.skipTo(0);
+    doc = spans.doc();
+    
+    // LUCENE-1583:
+    // according to Spans, a skipTo to the same doc or less
+    // should still call next() on the underlying Spans
+    assertEquals(1, doc);
+
+  }
+  
   public void testSpanOrDouble() throws Exception {
     Spans spans = orSpans(new String[] {"w5", "yy"});
     tstNextSpans(spans, 0, 4, 5);