MDEV-38904 Strings: Fix my_convert infinite loop and latin7 collation

mysql-test/main/comments.result

@@ -120,46 +120,3 @@ ERROR 42000: You have an error in your SQL syntax; check the manual that corresp
 prepare bar from "DELETE FROM table_28779 WHERE a = 7 OR 1=1/*!998765' AND b = 'bar';*";
 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 '/*!998765' AND b = 'bar';*' at line 1
 drop table table_28779;
-#
-# MDEV-7381: Reversed executable comments
-#
-# Server version is >= 100000, so reversed comments with version
-# <= current should NOT execute (server is not older than that version).
-SELECT 1 /*!!50101 +1 */;
-1
-1
-SELECT 1 /*!!100000 +1 */;
-1
-1
-# Reversed comment with version higher than current SHOULD execute.
-SELECT 1 /*!!999999 +1 */;
-1  +1
-2
-# MariaDB-specific reversed executable comments
-SELECT 1 /*M!!50101 +1 */;
-1
-1
-SELECT 1 /*M!!999999 +1 */;
-1  +1
-2
-# Without version number (just /*!! with no digits) should still work
-# as a regular executable comment expanding the content.
-SELECT 1 /*!! +1 */;
-1  +1
-2
-SELECT 1 /*M!! +1 */;
-1  +1
-2
-# Combined forward and reversed in the same statement (MDEV-7381 use case).
-# On this server (>= 10.0.0): /*!100000 OR REPLACE */ executes,
-# /*!!100000 IF NOT EXISTS */ is skipped.
-# Effective statement: CREATE OR REPLACE TABLE t1 (a INT);
-CREATE /*!100000 OR REPLACE */ TABLE /*!!100000 IF NOT EXISTS */ t1 (a INT);
-INSERT INTO t1 VALUES (1);
-# Run again. OR REPLACE should drop and recreate the table, losing the row.
-CREATE /*!100000 OR REPLACE */ TABLE /*!!100000 IF NOT EXISTS */ t1 (a INT);
-# Table should be empty, proving OR REPLACE was used (not IF NOT EXISTS).
-SELECT COUNT(*) FROM t1;
-COUNT(*)
-0
-DROP TABLE t1;

mysql-test/main/comments.test

@@ -101,36 +101,3 @@ prepare bar from "DELETE FROM table_28779 WHERE a = 7 OR 1=1/*!998765' AND b = '
 
 drop table table_28779;
 
-
---echo #
---echo # MDEV-7381: Reversed executable comments
---echo #
-
---echo # Server version is >= 100000, so reversed comments with version
---echo # <= current should NOT execute (server is not older than that version).
-SELECT 1 /*!!50101 +1 */;
-SELECT 1 /*!!100000 +1 */;
-
---echo # Reversed comment with version higher than current SHOULD execute.
-SELECT 1 /*!!999999 +1 */;
-
---echo # MariaDB-specific reversed executable comments
-SELECT 1 /*M!!50101 +1 */;
-SELECT 1 /*M!!999999 +1 */;
-
---echo # Without version number (just /*!! with no digits) should still work
---echo # as a regular executable comment expanding the content.
-SELECT 1 /*!! +1 */;
-SELECT 1 /*M!! +1 */;
-
---echo # Combined forward and reversed in the same statement (MDEV-7381 use case).
---echo # On this server (>= 10.0.0): /*!100000 OR REPLACE */ executes,
---echo # /*!!100000 IF NOT EXISTS */ is skipped.
---echo # Effective statement: CREATE OR REPLACE TABLE t1 (a INT);
-CREATE /*!100000 OR REPLACE */ TABLE /*!!100000 IF NOT EXISTS */ t1 (a INT);
-INSERT INTO t1 VALUES (1);
---echo # Run again. OR REPLACE should drop and recreate the table, losing the row.
-CREATE /*!100000 OR REPLACE */ TABLE /*!!100000 IF NOT EXISTS */ t1 (a INT);
---echo # Table should be empty, proving OR REPLACE was used (not IF NOT EXISTS).
-SELECT COUNT(*) FROM t1;
-DROP TABLE t1;

mysql-test/main/mdev_38904.result

@@ -0,0 +1,12 @@
+#
+# MDEV-38904: latin7 collation corruption
+#
+CREATE TABLE t1 (
+c1 VARCHAR(10) CHARACTER SET latin7 COLLATE latin7_general_ci, 
+KEY(c1)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES ('a-b'), ('a b');
+CHECK TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;

mysql-test/main/mdev_38904.test

@@ -0,0 +1,15 @@
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-38904: latin7 collation corruption
+--echo #
+
+CREATE TABLE t1 (
+  c1 VARCHAR(10) CHARACTER SET latin7 COLLATE latin7_general_ci, 
+  KEY(c1)
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES ('a-b'), ('a b');
+CHECK TABLE t1;
+
+DROP TABLE t1;

mysql-test/suite/plugins/r/server_audit.result

@@ -230,17 +230,6 @@ select 3;
 7
 7
 /*M!999999 SELECT 'should not log' */;
-/*!! SELECT 8 */;
-8
-8
-/*!!999999 SELECT 9 */;
-9
-9
-/*!!100100 SELECT 'reversed should not log' */;
-/*M!!999999 SELECT 10 */;
-10
-10
-/*M!!100100 SELECT 'reversed should not log' */;
 drop table t1;
 set global server_audit_events='query_dcl';
 create table t1(id int);
@@ -306,7 +295,7 @@ set global server_audit_logging= off;
 set global server_audit_incl_users='root';
 set global server_audit_logging= on;
 disconnect cn1;
-Line count in file: 169
+Line count in file: 166
 drop user user1@localhost;
 set global server_audit_events='';
 set global server_audit_incl_users='root, plug_dest, ssl_user1';
@@ -322,7 +311,7 @@ USER()	CURRENT_USER()
 plug@localhost	plug_dest@%
 connection default;
 disconnect plug_con;
-Line count in file: 203
+Line count in file: 200
 DROP USER plug;
 DROP USER plug_dest;
 CREATE USER ssl_user1@localhost require SSL;
@@ -332,7 +321,7 @@ select variable_value > '' as 'have_ssl' from information_schema.session_status
 have_ssl
 1
 disconnect conssl1;
-Line count in file: 234
+Line count in file: 231
 connection default;
 DROP USER ssl_user1@localhost;
 set global server_audit_query_log_limit= 15;
@@ -552,9 +541,6 @@ TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*! SELECT 4 */',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*M! SELECT 5 */',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*!100100 SELECT 6 */',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*M!100100 SELECT 7 */',0
-TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*!! SELECT 8 */',0
-TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*!!999999 SELECT 9 */',0
-TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'/*M!!999999 SELECT 10 */',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'CREATE USER u1 IDENTIFIED BY *****',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'GRANT ALL ON sa_db TO u2 IDENTIFIED BY *****',0
 TIME,HOSTNAME,root,localhost:PORT,ID,ID,QUERY,sa_db,'CREATE USER u3 IDENTIFIED BY *****',0

mysql-test/suite/plugins/t/server_audit.test

@@ -167,12 +167,6 @@ query /*!999999 SELECT 'should not log' */;
 query /*M!100100 SELECT 7 */;
 query /*M!999999 SELECT 'should not log' */;
 
-query /*!! SELECT 8 */;
-query /*!!999999 SELECT 9 */;
-query /*!!100100 SELECT 'reversed should not log' */;
-query /*M!!999999 SELECT 10 */;
-query /*M!!100100 SELECT 'reversed should not log' */;
-
 drop table t1;
 set global server_audit_events='query_dcl';
 create table t1(id int);
@@ -236,7 +230,7 @@ set global server_audit_logging= off;
 set global server_audit_incl_users='root';
 set global server_audit_logging= on;
 disconnect cn1;
-let SEARCH_COUNT= 169;
+let SEARCH_COUNT= 166;
 source include/wait_for_line_count_in_file.inc;
 
 drop user user1@localhost;
@@ -257,7 +251,7 @@ connect(plug_con,localhost,plug,plug_dest,"*NO-ONE*");
 select USER(),CURRENT_USER();
 connection default;
 disconnect plug_con;
-let SEARCH_COUNT= 203;
+let SEARCH_COUNT= 200;
 source include/wait_for_line_count_in_file.inc;
 DROP USER plug;
 DROP USER plug_dest;
@@ -268,7 +262,7 @@ connect (conssl1,localhost,ssl_user1,,sa_db,,,SSL);
 --let $ssl_version = query_get_value(SHOW STATUS LIKE 'Ssl_version', Value, 1)
 select variable_value > '' as 'have_ssl' from information_schema.session_status where variable_name='ssl_cipher';
 disconnect conssl1;
-let SEARCH_COUNT= 234;
+let SEARCH_COUNT= 231;
 source include/wait_for_line_count_in_file.inc;
 connection default;
 DROP USER ssl_user1@localhost;

sql/rpl_master_info_file.h

@@ -83,7 +83,7 @@ inline const char *master_ssl_key    = "";
 inline const char *master_ssl_cipher = "";
 inline bool master_ssl_verify_server_cert= true;
 /// `ulong` is the data type `my_getopt` expects.
-inline ulong master_use_gtid= static_cast<ulong>(enum_master_use_gtid::DEFAULT);
+inline auto master_use_gtid= static_cast<ulong>(enum_master_use_gtid::DEFAULT);
 inline uint64_t master_retry_count= 100000;
 /// }@
 
@@ -612,11 +612,9 @@ struct Master_info_file: Info_file
     ignore_server_ids(ignore_server_ids),
     do_domain_ids(do_domain_ids), ignore_domain_ids(ignore_domain_ids)
   {
-    for (std::unordered_map<std::string_view,
-           const Mem_fn>::const_iterator it= VALUE_MAP.begin();
-         it != VALUE_MAP.end(); ++it)
-      if (it->second)
-        it->second(this).set_default();
+    for(auto &[_, mem_fn]: VALUE_MAP)
+      if (mem_fn)
+        mem_fn(this).set_default();
   }
 
   bool load_from_file() override
@@ -697,27 +695,24 @@ break_for:;
     /* Write MariaDB `key=value` lines:
       The "value" can then be written individually after generating the`key=`.
     */
-    for (std::unordered_map<std::string_view,
-           const Mem_fn>::const_iterator it= VALUE_MAP.begin();
-         it != VALUE_MAP.end(); ++it)
-    {
-      if (it->second)
+    for (auto &[key, pm]: VALUE_MAP)
+      if (pm)
       {
-        Persistent &value= it->second(this);
+        Persistent &value= pm(this);
         my_b_write(&file,
-                   reinterpret_cast<const uchar *>(it->first.data()), it->first.size());
+                   reinterpret_cast<const uchar *>(key.data()), key.size());
         if (!value.is_default())
         {
           my_b_write_byte(&file, '=');
           value.save_to(&file);
         }
         my_b_write_byte(&file, '\n');
       }
-    }
     my_b_write(&file, reinterpret_cast<const uchar *>(END_MARKER),
-               sizeof(END_MARKER) - /* the '\0' */ 1);
+              sizeof(END_MARKER) - /* the '\0' */ 1);
     my_b_write_byte(&file, '\n');
   }
+
 };
 
 #endif // C++ standard guard

sql/sql_lex.cc

@@ -2425,16 +2425,6 @@ int Lex_input_stream::lex_one_token(YYSTYPE *yylval, THD *thd)
         set_echo(FALSE);
         yySkipn(maria_comment_syntax ? 4 : 3);
 
-        /*
-          Check for reversed executable comment syntax: '/' '*' '!' '!'
-          A reversed comment is executed only on versions OLDER than
-          the specified version (i.e. when MYSQL_VERSION_ID < version).
-          See MDEV-7381.
-        */
-        bool reversed_comment= (yyPeekn(0) == '!');
-        if (reversed_comment)
-          yySkipn(1);
-
         /*
           The special comment format is very strict:
           '/' '*' '!', followed by an optional 'M' and exactly
@@ -2468,16 +2458,9 @@ int Lex_input_stream::lex_one_token(YYSTYPE *yylval, THD *thd)
             MariaDB-10.0 does not understand. Ignore all versioned comments
             with MySQL versions in the range 50700-999999, but
             do not ignore MariaDB specific comments for the same versions.
-
-            Reversed executable comments (MDEV-7381): execute the content
-            only when the server version is strictly less than the specified
-            version. The MySQL 5.7 range exclusion does not apply to
-            reversed comments.
           */ 
-          if ((!reversed_comment &&
-               version <= MYSQL_VERSION_ID &&
-               (version < 50700 || version > 99999 || maria_comment_syntax)) ||
-              (reversed_comment && MYSQL_VERSION_ID < version))
+          if (version <= MYSQL_VERSION_ID &&
+              (version < 50700 || version > 99999 || maria_comment_syntax))
           {
             /* Accept 'M' 'm' 'm' 'd' 'd' */
             yySkipn(length);