MDEV-7387 [PATCH] Alter table xxx CHARACTER SET utf8, CONVERT TO CHARACTER SET latin1 should fail

A contribution from Daniel Black, with minor additional enhancements.

mysql-test/r/ctype_create.result

@@ -76,3 +76,35 @@ ALTER DATABASE aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ERROR 42000: Incorrect database name 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
 ALTER DATABASE `` DEFAULT CHARACTER SET latin2;
 ERROR 42000: Incorrect database name ''
+USE test;
+#
+# Start of 10.0 tests
+#
+#
+# MDEV-7387 Alter table xxx CHARACTER SET utf8, CONVERT TO CHARACTER SET latin1 should fail
+#
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET DEFAULT, CHARACTER SET utf8;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET DEFAULT' and 'CHARACTER SET utf8'
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET utf8, CHARACTER SET DEFAULT;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET utf8' and 'CHARACTER SET DEFAULT'
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET utf8, CHARACTER SET utf8;
+DROP TABLE t1;
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET DEFAULT, CHARACTER SET DEFAULT;
+DROP TABLE t1;
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1, b VARCHAR(10) CHARACTER SET utf8);
+ALTER TABLE t1 CONVERT TO CHARACTER SET utf8, CHARACTER SET latin1;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET utf8' and 'CHARACTER SET latin1'
+ALTER TABLE t1 CONVERT TO CHARACTER SET utf8, CHARACTER SET DEFAULT;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET utf8' and 'CHARACTER SET DEFAULT'
+ALTER TABLE t1 CONVERT TO CHARACTER SET latin1, CHARACTER SET utf8;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET latin1' and 'CHARACTER SET utf8'
+ALTER TABLE t1 CONVERT TO CHARACTER SET latin1, CHARACTER SET DEFAULT;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET latin1' and 'CHARACTER SET DEFAULT'
+ALTER TABLE t1 CONVERT TO CHARACTER SET DEFAULT, CHARACTER SET utf8;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET latin5' and 'CHARACTER SET utf8'
+ALTER TABLE t1 CONVERT TO CHARACTER SET DEFAULT, CHARACTER SET latin1;
+ERROR HY000: Conflicting declarations: 'CHARACTER SET latin5' and 'CHARACTER SET latin1'
+DROP TABLE t1;
+#
+# End of 10.0 tests
+#

mysql-test/t/ctype_create.test

@@ -105,3 +105,39 @@ ALTER DATABASE DEFAULT CHARACTER SET latin2;
 ALTER DATABASE aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa DEFAULT CHARACTER SET latin2;
 --error 1102
 ALTER DATABASE `` DEFAULT CHARACTER SET latin2;
+USE test;
+
+--echo #
+--echo # Start of 10.0 tests
+--echo #
+
+--echo #
+--echo # MDEV-7387 Alter table xxx CHARACTER SET utf8, CONVERT TO CHARACTER SET latin1 should fail
+--echo #
+--error ER_CONFLICTING_DECLARATIONS
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET DEFAULT, CHARACTER SET utf8;
+--error ER_CONFLICTING_DECLARATIONS
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET utf8, CHARACTER SET DEFAULT;
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET utf8, CHARACTER SET utf8;
+DROP TABLE t1;
+CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET DEFAULT, CHARACTER SET DEFAULT;
+DROP TABLE t1;
+
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1, b VARCHAR(10) CHARACTER SET utf8);
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET utf8, CHARACTER SET latin1;
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET utf8, CHARACTER SET DEFAULT;
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET latin1, CHARACTER SET utf8;
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET latin1, CHARACTER SET DEFAULT;
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET DEFAULT, CHARACTER SET utf8;
+--error ER_CONFLICTING_DECLARATIONS
+ALTER TABLE t1 CONVERT TO CHARACTER SET DEFAULT, CHARACTER SET latin1;
+DROP TABLE t1;
+
+--echo #
+--echo # End of 10.0 tests
+--echo #

sql/handler.cc

@@ -6296,3 +6296,22 @@ fl_create_iterator(enum handler_iterator_type type,
   }
 }
 #endif /*TRANS_LOG_MGM_EXAMPLE_CODE*/
+
+
+bool HA_CREATE_INFO::check_conflicting_charset_declarations(CHARSET_INFO *cs)
+{
+  if ((used_fields & HA_CREATE_USED_DEFAULT_CHARSET) &&
+      /* DEFAULT vs explicit, or explicit vs DEFAULT */
+      (((default_table_charset == NULL) != (cs == NULL)) ||
+      /* Two different explicit character sets */
+       (default_table_charset && cs &&
+        !my_charset_same(default_table_charset, cs))))
+  {
+    my_error(ER_CONFLICTING_DECLARATIONS, MYF(0),
+             "CHARACTER SET ", default_table_charset ?
+                               default_table_charset->csname : "DEFAULT",
+             "CHARACTER SET ", cs ? cs->csname : "DEFAULT");
+    return true;
+  }
+  return false;
+}

sql/handler.h

@@ -1637,6 +1637,33 @@ struct HA_CREATE_INFO
   bool table_was_deleted;
 
   bool tmp_table() { return options & HA_LEX_CREATE_TMP_TABLE; }
+  bool check_conflicting_charset_declarations(CHARSET_INFO *cs);
+  bool add_table_option_default_charset(CHARSET_INFO *cs)
+  {
+    // cs can be NULL, e.g.:  CREATE TABLE t1 (..) CHARACTER SET DEFAULT;
+    if (check_conflicting_charset_declarations(cs))
+      return true;
+    default_table_charset= cs;
+    used_fields|= HA_CREATE_USED_DEFAULT_CHARSET;
+    return false;
+  }
+  bool add_alter_list_item_convert_to_charset(CHARSET_INFO *cs)
+  {
+    /* 
+      cs cannot be NULL, as sql_yacc.yy translates
+         CONVERT TO CHARACTER SET DEFAULT
+      to
+         CONVERT TO CHARACTER SET <character-set-of-the-current-database>
+      TODO: Should't we postpone resolution of DEFAULT until the
+      character set of the table owner database is loaded from its db.opt?
+    */
+    DBUG_ASSERT(cs);
+    if (check_conflicting_charset_declarations(cs))
+      return true;
+    table_charset= default_table_charset= cs;
+    used_fields|= (HA_CREATE_USED_CHARSET | HA_CREATE_USED_DEFAULT_CHARSET);  
+    return false;
+  }
 };
 
 

sql/sql_yacc.yy

@@ -5803,18 +5803,8 @@ create_table_option:
 default_charset:
           opt_default charset opt_equal charset_name_or_default
           {
-            HA_CREATE_INFO *cinfo= &Lex->create_info;
-            if ((cinfo->used_fields & HA_CREATE_USED_DEFAULT_CHARSET) &&
-                 cinfo->default_table_charset && $4 &&
-                 !my_charset_same(cinfo->default_table_charset,$4))
-            {
-              my_error(ER_CONFLICTING_DECLARATIONS, MYF(0),
-                       "CHARACTER SET ", cinfo->default_table_charset->csname,
-                       "CHARACTER SET ", $4->csname);
+            if (Lex->create_info.add_table_option_default_charset($4))
               MYSQL_YYABORT;
-            }
-            Lex->create_info.default_table_charset= $4;
-            Lex->create_info.used_fields|= HA_CREATE_USED_DEFAULT_CHARSET;
           }
         ;
 
@@ -7646,10 +7636,8 @@ alter_list_item:
               MYSQL_YYABORT;
             }
             LEX *lex= Lex;
-            lex->create_info.table_charset=
-            lex->create_info.default_table_charset= $5;
-            lex->create_info.used_fields|= (HA_CREATE_USED_CHARSET |
-              HA_CREATE_USED_DEFAULT_CHARSET);
+            if (lex->create_info.add_alter_list_item_convert_to_charset($5))
+              MYSQL_YYABORT;
             lex->alter_info.flags|= Alter_info::ALTER_CONVERT;
           }
         | create_table_options_space_separated