bugfix: fix the problem of building undoLog exception when update joi…

…n does not update data (#6994)

changes/en-us/2.x.md

@@ -23,6 +23,7 @@ Add changes here for all PR submitted to the 2.x branch.
 - [[#6948](https://github.com/apache/incubator-seata/pull/6948)] Fix the CI build issue on the ARM64 platform
 - [[#6947](https://github.com/apache/incubator-seata/pull/6947)] fix npe for nacos registry when look up address
 - [[#6984](https://github.com/apache/incubator-seata/pull/6984)] support building docker image on openjdk23
+- [[#6994](https://github.com/apache/incubator-seata/pull/6994)] fix the problem of building undoLog exception when update join does not update data
 
 ### optimize:
 - [[#6826](https://github.com/apache/incubator-seata/pull/6826)] remove the branch registration operation of the XA read-only transaction

changes/zh-cn/2.x.md

@@ -23,6 +23,8 @@
 - [[#6948](https://github.com/apache/incubator-seata/pull/6948)] 修复在ARM64平台下CI构建出错的问题
 - [[#6947](https://github.com/apache/incubator-seata/pull/6947)] 修复nacos注册中心查询可用地址时的空指针问题
 - [[#6984](https://github.com/apache/incubator-seata/pull/6984)] 修复 openjdk23 版本下无法构建 docker 镜像的问题
+- [[#6994](https://github.com/apache/incubator-seata/pull/6994)] 修复updateJoin语句未更新到数据时prepareUndoLog异常
+
 
 ### optimize:
 - [[#6826](https://github.com/apache/incubator-seata/pull/6826)] 移除只读XA事务的分支注册操作

rm-datasource/src/main/java/org/apache/seata/rm/datasource/exec/mysql/MySQLUpdateJoinExecutor.java

@@ -91,7 +91,11 @@ protected TableRecords beforeImage() throws SQLException {
             }
             String selectSQL = buildBeforeImageSQL(joinTable, tableItems[i], suffixCommonCondition, itemTableUpdateColumns);
             TableRecords tableRecords = buildTableRecords(getTableMeta(tableItems[i]), selectSQL, paramAppenderList);
-            beforeImagesMap.put(tableItems[i], tableRecords);
+            if (CollectionUtils.isNotEmpty(tableRecords.getRows())) {
+                //when building the after image, the table with empty records in before image is skipped
+                //link issue https://github.com/apache/incubator-seata/issues/6976
+                beforeImagesMap.put(tableItems[i], tableRecords);
+            }
         }
         return null;
     }
@@ -231,6 +235,9 @@ private List<String> getItemUpdateColumns(TableMeta itemTableMeta, List<String>
 
     @Override
     protected void prepareUndoLog(TableRecords beforeImage, TableRecords afterImage) throws SQLException {
+        if (CollectionUtils.isEmpty(beforeImagesMap) && CollectionUtils.isEmpty(afterImagesMap)) {
+            return;
+        }
         if (CollectionUtils.isEmpty(beforeImagesMap) || CollectionUtils.isEmpty(afterImagesMap)) {
             throw new IllegalStateException("images can not be null");
         }

rm-datasource/src/test/java/org/apache/seata/rm/datasource/exec/UpdateJoinExecutorTest.java

@@ -76,6 +76,36 @@ public void testUpdateJoinUndoLog() throws SQLException {
         Assertions.assertDoesNotThrow(()->mySQLUpdateJoinExecutor.prepareUndoLog(beforeImage, afterImage));
     }
 
+    @Test
+    public void testEmptyUpdateJoinUndoLog() throws SQLException {
+        List<String> returnValueColumnLabels = Lists.newArrayList("id", "name");
+        Object[][] columnMetas = new Object[][]{
+                new Object[]{"", "", "t1", "id", Types.INTEGER, "INTEGER", 64, 0, 10, 1, "", "", 0, 0, 64, 1, "NO", "YES"},
+                new Object[]{"", "", "t1", "name", Types.VARCHAR, "VARCHAR", 64, 0, 10, 0, "", "", 0, 0, 64, 2, "YES", "NO"},
+                new Object[]{"", "", "t2", "id", Types.INTEGER, "INTEGER", 64, 0, 10, 1, "", "", 0, 0, 64, 1, "NO", "YES"},
+                new Object[]{"", "", "t2", "name", Types.VARCHAR, "VARCHAR", 64, 0, 10, 0, "", "", 0, 0, 64, 2, "YES", "NO"},
+                new Object[]{"", "", "t1 inner join t2 on t1.id = t2.id", "id", Types.VARCHAR, "VARCHAR", 64, 0, 10, 0, "", "", 0, 0, 64, 2, "YES", "NO"},
+                new Object[]{"", "", "t1 inner join t2 on t1.id = t2.id", "name", Types.VARCHAR, "VARCHAR", 64, 0, 10, 0, "", "", 0, 0, 64, 2, "YES", "NO"},
+        };
+        Object[][] indexMetas = new Object[][]{
+                new Object[]{"PRIMARY", "id", false, "", 3, 1, "A", 34},
+        };
+        Object[][] beforeReturnValue = new Object[][]{};
+        StatementProxy beforeMockStatementProxy = mockStatementProxy(returnValueColumnLabels, beforeReturnValue, columnMetas, indexMetas);
+        String sql = "update t1 inner join t2 on t1.id = t2.id set t1.name = 'WILL',t2.name = 'WILL'";
+        List<SQLStatement> asts = SQLUtils.parseStatements(sql, JdbcConstants.MYSQL);
+        MySQLUpdateRecognizer recognizer = new MySQLUpdateRecognizer(sql, asts.get(0));
+        UpdateExecutor mySQLUpdateJoinExecutor = new MySQLUpdateJoinExecutor(beforeMockStatementProxy, (statement, args) -> {
+            return null;
+        }, recognizer);
+        TableRecords beforeImage = mySQLUpdateJoinExecutor.beforeImage();
+        Object[][] afterReturnValue = new Object[][]{};
+        StatementProxy afterMockStatementProxy = mockStatementProxy(returnValueColumnLabels, afterReturnValue, columnMetas, indexMetas);
+        mySQLUpdateJoinExecutor.statementProxy = afterMockStatementProxy;
+        TableRecords afterImage = mySQLUpdateJoinExecutor.afterImage(beforeImage);
+        Assertions.assertDoesNotThrow(()->mySQLUpdateJoinExecutor.prepareUndoLog(beforeImage, afterImage));
+    }
+
     private StatementProxy mockStatementProxy(List<String> returnValueColumnLabels, Object[][] returnValue, Object[][] columnMetas, Object[][] indexMetas) {
         MockDriver mockDriver = new MockDriver(returnValueColumnLabels, returnValue, columnMetas, indexMetas);
         DruidDataSource dataSource = new DruidDataSource();