SOLR-4303: On replication, if the generation of the master is lower than the slave we need to force a full copy of the index.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1432993 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -516,6 +516,9 @@ Bug Fixes
 * SOLR-4217: post.jar no longer ignores -Dparams when -Durl is used.
   (Alexandre Rafalovitch, ehatcher)
 
+* SOLR-4303: On replication, if the generation of the master is lower than the
+  slave we need to force a full copy of the index. (Mark Miller, Gregg Donovan)
+
 Other Changes
 ----------------------
 

solr/core/src/java/org/apache/solr/handler/SnapPuller.java

@@ -370,7 +370,9 @@ public class SnapPuller {
       filesDownloaded = Collections.synchronizedList(new ArrayList<Map<String, Object>>());
       // if the generateion of master is older than that of the slave , it means they are not compatible to be copied
       // then a new index direcory to be created and all the files need to be copied
-      boolean isFullCopyNeeded = IndexDeletionPolicyWrapper.getCommitTimestamp(commit) >= latestVersion || forceReplication;
+      boolean isFullCopyNeeded = IndexDeletionPolicyWrapper
+          .getCommitTimestamp(commit) >= latestVersion
+          || commit.getGeneration() >= latestGeneration || forceReplication;
 
       String tmpIdxDirName = "index." + new SimpleDateFormat(SnapShooter.DATE_FMT, Locale.ROOT).format(new Date());
       tmpIndex = createTempindexDir(core, tmpIdxDirName);