Core/Players: Prevent creation of characters with duplicate names

Closes #30299

(cherry picked from commit 49ab2bbe3883749594fe92a752e1d618c625d1b6)

2 files changed, 34 insertions, 4 deletions

diff --git a/sql/base/characters_database.sql b/sql/base/characters_database.sql
index b156dc50965..f90bcca4bec 100644
--- a/sql/base/characters_database.sql
+++ b/sql/base/characters_database.sql
@@ -1692,7 +1692,7 @@ DROP TABLE IF EXISTS `characters`;
 CREATE TABLE `characters` (
   `guid` bigint unsigned NOT NULL DEFAULT '0' COMMENT 'Global Unique Identifier',
   `account` int unsigned NOT NULL DEFAULT '0' COMMENT 'Account Identifier',
-  `name` varchar(12) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
+  `name` varchar(12) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL,
   `slot` tinyint unsigned NOT NULL DEFAULT '0',
   `race` tinyint unsigned NOT NULL DEFAULT '0',
   `class` tinyint unsigned NOT NULL DEFAULT '0',
@@ -1777,9 +1777,9 @@ CREATE TABLE `characters` (
   `personalTabardBorderColor` int NOT NULL DEFAULT '-1',
   `personalTabardBackgroundColor` int NOT NULL DEFAULT '-1',
   PRIMARY KEY (`guid`),
+  UNIQUE KEY `idx_name` (`name`),
   KEY `idx_account` (`account`),
-  KEY `idx_online` (`online`),
-  KEY `idx_name` (`name`)
+  KEY `idx_online` (`online`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='Player System';
 /*!40101 SET character_set_client = @saved_cs_client */;
 
@@ -3380,7 +3380,8 @@ INSERT INTO `updates` VALUES
 ('2024_07_27_00_characters.sql','912ADCAC4948C75386387251D6FAEFB841574606','RELEASED','2024-07-27 01:03:05',0),
 ('2024_07_28_00_characters.sql','22C94D231C155686691780B65C12FCC2B4C3A6AA','RELEASED','2024-07-28 00:59:04',0),
 ('2024_08_27_00_characters_2024_08_26_00_characters.sql','68EEBE1D639D59B24F5121008C2D103CA67FFC9A','RELEASED','2024-08-27 17:15:49',0),
-('2024_09_01_00_characters.sql','B921A034AFAB2BFFF3EDA6EE9AB3152EFE503734','RELEASED','2024-09-01 20:45:47',0);
+('2024_09_01_00_characters.sql','B921A034AFAB2BFFF3EDA6EE9AB3152EFE503734','RELEASED','2024-09-01 20:45:47',0),
+('2024_10_03_00_characters.sql','408249A6992999A36EB94089D184972E8E0767A3','RELEASED','2024-10-03 11:10:18',0);
 /*!40000 ALTER TABLE `updates` ENABLE KEYS */;
 UNLOCK TABLES;
 
diff --git a/sql/updates/characters/cata_classic/2024_10_03_00_characters.sql b/sql/updates/characters/cata_classic/2024_10_03_00_characters.sql
new file mode 100644
index 00000000000..7b5a6fcf357
--- /dev/null
+++ b/sql/updates/characters/cata_classic/2024_10_03_00_characters.sql
@@ -0,0 +1,29 @@
+-- append guid as hex to characters who have duplicate names in database except the one with lowest guid (assumed to have been created first)
+-- and flag them for rename
+CREATE TEMPORARY TABLE `characters_to_rename` SELECT
+    c2.`guid`
+  FROM
+    (
+      SELECT
+        c1.`name` AS `name`,
+        MIN(c1.`guid`) AS originalGuid
+      FROM
+        `characters` c1 
+      WHERE
+        LENGTH(c1.`name`) > 0 
+      GROUP BY
+        1 
+      HAVING
+        COUNT(*) > 1
+    ) c3
+    INNER JOIN `characters` c2 ON c3.`name` = c2.`name`
+  WHERE
+    c2.guid <> c3.originalGuid;
+
+UPDATE `characters` SET `name` = CONCAT(SUBSTRING(`name` FROM 1 FOR 12 - LENGTH(CONV(`guid`, 10, 16))), CONV(`guid`, 10, 16)), `at_login` = `at_login` | 1 WHERE `guid` IN (SELECT `guid` FROM `characters_to_rename`);
+
+-- recreate name index with unique constraint
+ALTER TABLE `characters` DROP INDEX `idx_name`;
+ALTER TABLE `characters` MODIFY COLUMN `name` varchar(12) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL AFTER `account`;
+UPDATE `characters` SET `name` = NULL WHERE `name` = '';
+ALTER TABLE `characters` ADD UNIQUE INDEX `idx_name` (`name` ASC);