From 1f6833c72d934fe4d9d0233321a9a6dc5f8cff08 Mon Sep 17 00:00:00 2001
From: Yegor Kozlov <yegor@apache.org>
Date: Sat, 11 Sep 2010 13:48:00 +0000
Subject: [PATCH] avoid corruption of XSSFWorkbook after removing all merged
 cells from sheet, see Bugzilla 49895

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@996148 13f79535-47bb-0310-9956-ffa450edef68
---
 src/documentation/content/xdocs/status.xml                  | 1 +
 src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java | 6 +++++-
 .../org/apache/poi/xssf/usermodel/TestXSSFSheet.java        | 2 ++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/documentation/content/xdocs/status.xml b/src/documentation/content/xdocs/status.xml
index a837169ed..0e77fa1bd 100644
--- a/src/documentation/content/xdocs/status.xml
+++ b/src/documentation/content/xdocs/status.xml
@@ -34,6 +34,7 @@
 
     <changes>
         <release version="3.7-beta3" date="2010-??-??">
+           <action dev="poi-developers" type="fix">49895 - avoid corruption of XSSFWorkbook after removing all merged cells from sheet</action>
            <action dev="poi-developers" type="fix">49907 - fixed inconsistent behaviour between HSSF and XSSF when creating consecutive names</action>
            <action dev="poi-developers" type="add">Add getMimeType() method to HWPF Picture, alongside existing file extension</action>
            <action dev="poi-developers" type="add">Add code for reading Ole10Native data</action>
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java
index d33bea8f9..ce870cfcf 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java
@@ -1350,7 +1350,11 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
                 mergeCellsArray[i - 1] = ctMergeCells.getMergeCellArray(i);
             }
         }
-        ctMergeCells.setMergeCellArray(mergeCellsArray);
+        if(mergeCellsArray.length > 0){
+            ctMergeCells.setMergeCellArray(mergeCellsArray);
+        } else{
+            worksheet.unsetMergeCells();
+        }
     }
 
     /**
diff --git a/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java b/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java
index 7eec1794a..f38d773e6 100644
--- a/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java
+++ b/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java
@@ -253,6 +253,8 @@ public final class TestXSSFSheet extends BaseTestSheet {
         sheet.removeMergedRegion(1);
         sheet.removeMergedRegion(0);
         assertEquals(0, sheet.getNumMergedRegions());
+        assertNull(" CTMergeCells should be deleted after removing the last merged " +
+                "region on the sheet.", sheet.getCTWorksheet().getMergeCells());
     }
 
     public void testSetDefaultColumnStyle() {