From 58a145fbba238b26551586afe074ae644916d78a Mon Sep 17 00:00:00 2001
From: Timothy Potter <thelabdude@apache.org>
Date: Mon, 13 Oct 2014 15:35:35 +0000
Subject: [PATCH] SOLR-6511: fix back compat issue when reading existing data
 from ZK

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1631439 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/solr/cloud/ZkController.java   | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/solr/core/src/java/org/apache/solr/cloud/ZkController.java b/solr/core/src/java/org/apache/solr/cloud/ZkController.java
index abe054650f3..fe1e36906fd 100644
--- a/solr/core/src/java/org/apache/solr/cloud/ZkController.java
+++ b/solr/core/src/java/org/apache/solr/cloud/ZkController.java
@@ -1989,8 +1989,18 @@ public final class ZkController {
     }
 
     Map<String,Object> stateObj = null;
-    if (stateData != null && stateData.length > 0)
-      stateObj = (Map<String, Object>) ZkStateReader.fromJSON(stateData);
+    if (stateData != null && stateData.length > 0) {
+      Object parsedJson = ZkStateReader.fromJSON(stateData);
+      if (parsedJson instanceof Map) {
+        stateObj = (Map<String,Object>)parsedJson;
+      } else if (parsedJson instanceof String) {
+        // old format still in ZK
+        stateObj = new LinkedHashMap<>();
+        stateObj.put("state", (String)parsedJson);
+      } else {
+        throw new SolrException(ErrorCode.SERVER_ERROR, "Leader-initiated recovery state data is invalid! "+parsedJson);
+      }
+    }
 
     return stateObj;
   }