LUCENE-4209: Enforce cleanup on success and failure while sorting partitions

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1359953 13f79535-47bb-0310-9956-ffa450edef68

lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/Sort.java

@@ -193,6 +193,8 @@ public final class Sort {
     output.delete();
 
     ArrayList<File> merges = new ArrayList<File>();
+    boolean success2 = false;
+    try {
       ByteSequencesReader is = new ByteSequencesReader(input);
       boolean success = false;
       try {
@@ -205,12 +207,15 @@ public final class Sort {
           // Handle intermediate merges.
           if (merges.size() == maxTempFiles) {
             File intermediate = File.createTempFile("sort", "intermediate", tempDirectory);
+            try {
               mergePartitions(merges, intermediate);
+            } finally {
               for (File file : merges) {
                 file.delete();
               }
               merges.clear();
               merges.add(intermediate);
+            }
             sortInfo.tempMergeFiles++;
           }
         }
@@ -229,14 +234,19 @@ public final class Sort {
         // on a different volume or something. Copy the input then.
         if (!single.renameTo(output)) {
           copy(single, output);
-        single.delete();
         }
       } else { 
         // otherwise merge the partitions with a priority queue.
         mergePartitions(merges, output);
+      }
+      success2 = true;
+    } finally {
       for (File file : merges) {
         file.delete();
       }
+      if (!success2) {
+        output.delete();
+      }
     }
 
     sortInfo.totalTime = (System.currentTimeMillis() - sortInfo.totalTime);