Bug #48972 mysqldump --insert-ignore leaves set unique_checks=0.

Description:
By default mysqldump always appends set_unique_checks=0 to it's output. When using --insert-ignore --no-create-info to try to merge two sets of data the unique checks on secondary indexes are disabled causing duplicate rows. 

How to repeat:
mysqldump  -u root --database test -S /var/lib/mysql/mysql.sock --insert-ignore --no-create-info
-- MySQL dump 10.10
--
-- Host: localhost    Database: test
-- ------------------------------------------------------
-- Server version	5.0.27-standard

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;

--

Suggested fix:
Disable unique_checks=0 when --insert-ignore is used. 

http://ebergen.net/patches/mysqldump_unique_checks.patch

--- orig/client/mysqldump.c	2009-01-13 05:02:01.000000000 -0800
+++ patched/client/mysqldump.c	2009-11-22 11:52:49.000000000 -0800
@@ -594,8 +594,13 @@
 
     if (!path)
     {
+      if (!opt_ignore)
+      {
+        fprintf(md_result_file,"\
+/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;\n");
+      }
+
       fprintf(md_result_file,"\
-/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;\n\
 /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;\n\
 ");
     }
@@ -625,8 +630,13 @@
     if (!path)
     {
       fprintf(md_result_file,"\
-/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;\n\
+/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;\n");
+
+      if (!opt_ignore)
+      {
+        fprintf(md_result_file,"\
 /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;\n");
+      }
     }
     if (opt_set_charset)
       fprintf(sql_file,

Thank you for the feature request and code contributed.

This bug is 500 days old. Is there any chance of it being fixed?

This has been verified for just over 1000 days..