MDEV-39788: Fix master.info not upgrading master_use_gtid

debian/mariadb-test-data.lintian-overrides

@@ -411,6 +411,7 @@ package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-te
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/mariadb-conv/file01.utf8.txt]
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/mariadb-conv/file02.latin1.txt]
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/mysql5613mysql/README]
+package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/new-format-master.info]
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/new-format-relay-log-win.info]
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/new-format-relay-log.info]
 package-contains-documentation-outside-usr-share-doc [usr/share/mysql/mariadb-test/std_data/numbers.txt]

mysql-test/main/rpl_read_new_info.result

@@ -0,0 +1,10 @@
+CHANGE MASTER TO master_host='127.0.0.1';
+# restart: --skip-slave-start
+Master_Log_File = 'mysqld-bin.000002'
+Read_Master_Log_Pos = '2147483648'
+Master_SSL_Key = ''
+Using_Gtid = 'Current_Pos'
+Relay_Master_Log_File = 'mysqld-bin.000001'
+Exec_Master_Log_Pos = '2147483648'
+SQL_Delay = '5'
+RESET SLAVE ALL;

mysql-test/main/rpl_read_new_info.test

@@ -0,0 +1,41 @@
+# Verify that the post-WL#344 format of `*.info` can be parsed.
+# * Verify that the line count includes the line-count line in
+#   `@@master_info_file` while excludes it in `@@relay_log_info_file`
+#   (Reference: MDEV-39788 master.info is read and
+#    written one line too many compared to before)
+# * Verify that position values > 2^31 can be read
+#   (MDEV-38020: Master & relay log info files read 2^31 and above incorrectly)
+
+--source include/have_binlog_format_mixed.inc # format-agnostic
+CHANGE MASTER TO master_host='127.0.0.1'; # have_info_files
+
+--let $MYSQLD_DATADIR= `SELECT @@datadir`
+
+# the new version of relay_log.info comes in two versions: with path
+# separator '/' (most systems) and with path separator '\' (windows)
+if ($SYSTEM_PATH_SEPARATOR != /) {
+  --let $file_suffix= -win
+}
+
+
+--source include/shutdown_mysqld.inc
+
+  --remove_file $MYSQLD_DATADIR/master.info
+  # `Using_Gtid` is the key-value section, not the 33rd option.
+  --copy_file $MYSQL_TEST_DIR/std_data/new-format-master.info $MYSQLD_DATADIR/master.info
+
+  # Check that the 5th option (`SQL_Delay`) is included.
+  --remove_file $MYSQLD_DATADIR/relay-log.info
+  --copy_file $MYSQL_TEST_DIR/std_data/new-format-relay-log$file_suffix.info $MYSQLD_DATADIR/relay-log.info
+
+--let $restart_parameters= --skip-slave-start
+--source include/start_mysqld.inc
+
+--let $status_items= Master_Log_File, Read_Master_Log_Pos, Master_SSL_Key, Using_Gtid, Relay_Master_Log_File, Exec_Master_Log_Pos, SQL_Delay
+--source include/show_slave_status.inc
+
+
+# Reset
+--disable_warnings
+  RESET SLAVE ALL;
+--enable_warnings

mysql-test/std_data/new-format-master.info

@@ -0,0 +1,34 @@
+33
+mysqld-bin.000002
+2147483648
+127.0.0.1
+root
+
+3306
+60
+1
+
+
+
+
+
+1
+60.000
+
+0
+
+100000
+
+
+
+
+
+
+
+
+
+
+
+
+
+using_gtid=1

mysql-test/std_data/new-format-relay-log-win.info

@@ -1,6 +1,6 @@
 5
-.\slave-relay-bin.000001
+.\mysqld-relay-bin.000001
 4
-
-0
-0
+mysqld-bin.000001
+2147483648
+5

mysql-test/std_data/new-format-relay-log.info

@@ -1,6 +1,6 @@
 5
-./slave-relay-bin.000001
+./mysqld-relay-bin.000001
 4
-
-0
-0
+mysqld-bin.000001
+2147483648
+5

sql/rpl_info_file.h

@@ -250,15 +250,15 @@ struct Info_file
     (Re)load the MySQL line-based section from the @ref file
     @param value_list
       List of wrapped member pointers to values. The first element must be a
-      file name @ref String_value to be unambiguous with the line count line.
+      file name @ref String_value to be unambiguous with the line-count line.
     @param default_line_count
       We cannot simply read lines until EOF as all versions
       of MySQL/MariaDB may generate more lines than needed.
       Therefore, starting with MySQL/MariaDB 4.1.x for @ref Master_info_file and
-      5.6.x for @ref Relay_log_info_file, the first line of the file is number
-      of one-line-per-value lines in the file, including this line count itself.
+      5.6.x/10.0.x for @ref Relay_log_info_file, the first line of the file is
+      the number of one-line-per-value lines in the file.
       This parameter specifies the number of effective lines before those
-      versions (i.e., not counting the line count line if it was to have one),
+      versions (i.e., not counting the line-count line if it was to have one),
       where the first line is a filename with extension
       (either contains a `.` or is entirely empty) rather than an integer.
     @return `false` if the file has parsed successfully or `true` if error
@@ -273,13 +273,13 @@ struct Info_file
     @param total_line_count
       The number of lines to describe the file as on the first line of the file.
       If this is larger than `value_list.size()`, suffix the file with empty
-      lines until the line count (including the line count line) is this many.
-      This reservation provides compatibility with MySQL,
-      who has added more old-style lines while MariaDB innovated.
+      lines until the line count (*excluding* the line-count line) is this many.
+      This reservation provides compatibility
+      with older versions of MySQL and MariaDB.
   */
   template<size_t size> void save_to_file(
     const Mem_fn (&value_list)[size],
-    size_t total_line_count= size + /* line count line */ 1
+    size_t total_line_count= size
   ) { return save_to_file(value_list, size, total_line_count); }
 
 private:
@@ -336,7 +336,7 @@ struct Info_file
 
   void save_to_file(const Mem_fn *values, size_t size, size_t total_line_count)
   {
-    DBUG_ASSERT(total_line_count > size);
+    DBUG_ASSERT(total_line_count >= size);
     my_b_seek(&file, 0);
     /*
       If the new contents take less space than the previous file contents,
@@ -353,12 +353,8 @@ struct Info_file
         pm(this).save_to(&file);
       my_b_write_byte(&file, '\n');
     }
-    /*
-      Pad additional reserved lines:
-      (1 for the line count line + line count) inclusive -> max line inclusive
-       = line count exclusive <- max line inclusive
-    */
-    for (; total_line_count > size; --total_line_count)
+    // Pad additional reserved lines
+    for (; size < total_line_count; ++size)
       my_b_write_byte(&file, '\n');
   }
 

sql/rpl_master_info_file.h

@@ -540,6 +540,25 @@ struct Master_info_file: Info_file
   /// }@
 
 
+protected:
+  /**
+    @ref Master_info_file has been inconsistent that its line count included
+    the line-count "value", while @ref Relay_log_info_file's excludes it.
+    Although the use common code now makes @ref Master_info_file match,
+    files from older versions are now off-by-one to Info_file::load_from_file().
+    The presence of this non-reading pseudo-value restores
+    compatibility with files generated by MariaDB 10.0+,
+    as the driver loop will increment the line counter for it,
+    thus emulating counting the line-count "value".
+    @deprecated This is not needed after all pre-12.3 versions go EoL.
+  */
+  struct: Persistent
+  {
+    bool load_from(IO_CACHE *file) override { return false; } ///< No-op
+    void save_to(IO_CACHE *file) override {} ///< No-op
+  } LINE_COUNT_FIX;
+public:
+
   inline static const Mem_fn VALUE_LIST[] {
     &Master_info_file::master_log_file,
     &Master_info_file::master_log_pos,
@@ -561,7 +580,9 @@ struct Master_info_file: Info_file
     nullptr, // MySQL `master_uuid`, which MariaDB ignores.
     &Master_info_file::master_retry_count,
     &Master_info_file::master_ssl_crl,
-    &Master_info_file::master_ssl_crlpath
+    &Master_info_file::master_ssl_crlpath,
+    // This must be last, so its blank line blend into trailing blank line(s).
+    &Master_info_file::LINE_COUNT_FIX
   };
 
   /**