MDEV-18463 Don't allow multiple table CONSTRAINTs with the same name.

Add necessary checks.

mysql-test/r/foreign_key.result

@@ -82,3 +82,29 @@ add foreign key (a) references t3 (a)
 on update set default on update set default);
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'update set default)' at line 3
 drop table t_34455;
+#
+# MDEV-18460 Don't allow multiple table CONSTRAINTs with the same name.
+#
+CREATE TABLE tpk (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,name VARCHAR(100) NOT NULL) ENGINE=Innodb;
+CREATE TABLE tfk (c1 INT, c2 INT, CONSTRAINT sid UNIQUE (c1), CONSTRAINT sid CHECK (c2>15));
+ERROR HY000: Duplicate CHECK constraint name 'sid'
+CREATE TABLE tfk (c1 INT, c2 INT, CONSTRAINT sid UNIQUE (c1));
+ALTER TABLE tfk ADD CONSTRAINT sid CHECK (c2>15);
+ERROR HY000: Duplicate CHECK constraint name 'sid'
+DROP TABLE tfk;
+CREATE TABLE tfk (c1 INT, c2 INT,
+CONSTRAINT sid FOREIGN KEY (c1) REFERENCES tpk (id)) ENGINE=Innodb;
+show create table tfk;
+Table	Create Table
+tfk	CREATE TABLE `tfk` (
+  `c1` int(11) DEFAULT NULL,
+  `c2` int(11) DEFAULT NULL,
+  KEY `sid` (`c1`),
+  CONSTRAINT `sid` FOREIGN KEY (`c1`) REFERENCES `tpk` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+ALTER TABLE tfk ADD CONSTRAINT sid CHECK (c2>15);
+ERROR HY000: Duplicate CHECK constraint name 'sid'
+ALTER TABLE tfk ADD CONSTRAINT sid UNIQUE(c2);
+ERROR 42000: Duplicate key name 'sid'
+DROP TABLE tfk;
+DROP TABLE tpk;

mysql-test/t/foreign_key.test

@@ -117,4 +117,28 @@ alter table t_34455
 
 drop table t_34455;
 
+--echo #
+--echo # MDEV-18460 Don't allow multiple table CONSTRAINTs with the same name.
+--echo #
+
+CREATE TABLE tpk (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,name VARCHAR(100) NOT NULL) ENGINE=Innodb;
+--error ER_DUP_CONSTRAINT_NAME
+CREATE TABLE tfk (c1 INT, c2 INT, CONSTRAINT sid UNIQUE (c1), CONSTRAINT sid CHECK (c2>15));
+
+CREATE TABLE tfk (c1 INT, c2 INT, CONSTRAINT sid UNIQUE (c1));
+--error ER_DUP_CONSTRAINT_NAME
+ALTER TABLE tfk ADD CONSTRAINT sid CHECK (c2>15);
+DROP TABLE tfk;
+
+CREATE TABLE tfk (c1 INT, c2 INT,
+  CONSTRAINT sid FOREIGN KEY (c1) REFERENCES tpk (id)) ENGINE=Innodb;
+show create table tfk;
+--error ER_DUP_CONSTRAINT_NAME
+ALTER TABLE tfk ADD CONSTRAINT sid CHECK (c2>15);
+--error ER_DUP_KEYNAME
+ALTER TABLE tfk ADD CONSTRAINT sid UNIQUE(c2);
+DROP TABLE tfk;
+
+DROP TABLE tpk;
+
 

sql/sql_table.cc

@@ -4196,10 +4196,10 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
         continue;
 
       {
-        /* Check that there's no repeating constraint names. */
+        /* Check that there's no repeating table CHECK constraint names. */
         List_iterator_fast<Virtual_column_info>
           dup_it(alter_info->check_constraint_list);
-        Virtual_column_info *dup_check;
+        const Virtual_column_info *dup_check;
         while ((dup_check= dup_it++) && dup_check != check)
         {
           if (check->name.length == dup_check->name.length &&
@@ -4212,6 +4212,27 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
         }
       }
 
+      /* Check that there's no repeating key constraint names. */
+      List_iterator_fast<Key> key_it(alter_info->key_list);
+      while (const Key *key= key_it++)
+      {
+        /*
+          Not all keys considered to be the CONSTRAINT
+          Noly Primary Key UNIQUE and Foreign keys.
+        */
+        if (key->type != Key::PRIMARY && key->type != Key::UNIQUE &&
+            key->type != Key::FOREIGN_KEY)
+          continue;
+
+        if (check->name.length == key->name.length &&
+            my_strcasecmp(system_charset_info,
+              check->name.str, key->name.str) == 0)
+        {
+          my_error(ER_DUP_CONSTRAINT_NAME, MYF(0), "CHECK", check->name.str);
+          DBUG_RETURN(TRUE);
+        }
+      }
+
       if (check_string_char_length(&check->name, 0, NAME_CHAR_LEN,
                                    system_charset_info, 1))
       {
@@ -8176,6 +8197,35 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
       }
     }
   }
+
+  if (!alter_info->check_constraint_list.is_empty())
+  {
+    /* Check the table FOREIGN KEYs for name duplications. */
+    List <FOREIGN_KEY_INFO> fk_child_key_list;
+    FOREIGN_KEY_INFO *f_key;
+    table->file->get_foreign_key_list(thd, &fk_child_key_list);
+    List_iterator<FOREIGN_KEY_INFO> fk_key_it(fk_child_key_list);
+    while ((f_key= fk_key_it++))
+    {
+      List_iterator_fast<Virtual_column_info>
+        c_it(alter_info->check_constraint_list);
+      Virtual_column_info *check;
+      while ((check= c_it++))
+      {
+        if (!check->name.length || check->automatic_name)
+          continue;
+
+        if (check->name.length == f_key->foreign_id->length &&
+            my_strcasecmp(system_charset_info, f_key->foreign_id->str,
+                          check->name.str) == 0)
+        {
+          my_error(ER_DUP_CONSTRAINT_NAME, MYF(0), "CHECK", check->name.str);
+          goto err;
+        }
+      }
+    }
+  }
+
   /* Add new constraints */
   new_constraint_list.append(&alter_info->check_constraint_list);