LUCENE-4137: BaseCompositeReader should throw exception if docids overflow

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1350047 13f79535-47bb-0310-9956-ffa450edef68

lucene/core/src/java/org/apache/lucene/index/BaseCompositeReader.java

@@ -70,6 +70,9 @@ public abstract class BaseCompositeReader<R extends IndexReader> extends Composi
       starts[i] = maxDoc;
       final IndexReader r = subReaders[i];
       maxDoc += r.maxDoc();      // compute maxDocs
+      if (maxDoc < 0 /* overflow */) {
+        throw new IllegalArgumentException("Too many documents, composite IndexReaders cannot exceed " + Integer.MAX_VALUE);
+      }
       numDocs += r.numDocs();    // compute numDocs
       if (r.hasDeletions()) {
         hasDeletions = true;

lucene/core/src/test/org/apache/lucene/index/Test2BDocs.java

@@ -0,0 +1,83 @@
+package org.apache.lucene.index;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.util.Arrays;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.util.LuceneTestCase;
+import org.apache.lucene.util._TestUtil;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+
+public class Test2BDocs extends LuceneTestCase {
+  static Directory dir;
+  
+  @BeforeClass
+  public static void beforeClass() throws Exception {
+    dir = newFSDirectory(_TestUtil.getTempDir("2Bdocs"));
+    IndexWriter iw = new IndexWriter(dir, new IndexWriterConfig(TEST_VERSION_CURRENT, null));
+    Document doc = new Document();
+    for (int i = 0; i < 262144; i++) {
+      iw.addDocument(doc);
+    }
+    iw.forceMerge(1);
+    iw.close();
+  }
+  
+  @AfterClass
+  public static void afterClass() throws Exception {
+    dir.close();
+    dir = null;
+  }
+
+  public void testOverflow() throws Exception {
+    DirectoryReader ir = DirectoryReader.open(dir);
+    IndexReader subReaders[] = new IndexReader[8192];
+    Arrays.fill(subReaders, ir);
+    try {
+      new MultiReader(subReaders);
+      fail();
+    } catch (IllegalArgumentException expected) {
+      // expected
+    }
+    ir.close();
+  }
+  
+  public void testExactlyAtLimit() throws Exception {
+    Directory dir2 = newFSDirectory(_TestUtil.getTempDir("2BDocs2"));
+    IndexWriter iw = new IndexWriter(dir2, new IndexWriterConfig(TEST_VERSION_CURRENT, null));
+    Document doc = new Document();
+    for (int i = 0; i < 262143; i++) {
+      iw.addDocument(doc);
+    }
+    iw.close();
+    DirectoryReader ir = DirectoryReader.open(dir);
+    DirectoryReader ir2 = DirectoryReader.open(dir2);
+    IndexReader subReaders[] = new IndexReader[8192];
+    Arrays.fill(subReaders, ir);
+    subReaders[subReaders.length-1] = ir2;
+    MultiReader mr = new MultiReader(subReaders);
+    assertEquals(Integer.MAX_VALUE, mr.maxDoc());
+    assertEquals(Integer.MAX_VALUE, mr.numDocs());
+    ir.close();
+    ir2.close();
+    dir2.close();
+  }
+}