Bug #74445 Unhelpful error for IO Thread

Description:
Situation: A 5.6 slave replicating from an older release after upgrading the slave.

Show in 'SHOW SLAVE STATUS' output:
Slave_IO_Running: Connecting
Last_IO_Errno: 2049
Last_IO_Error: error connecting to master 'xxxx@xxxxxxx:3306' - retry-time: 60  retries: 5

The perror utility is of no help.  
$ perror 2049
Illegal error code: 2049

It it listed in the reference manual:
http://dev.mysql.com/doc/refman/5.6/en/error-messages-client.html#error_cr_secure_auth

Lucklily I was able to change the password hash for the replication user on the master from a pre-4.1 hash to the newer format. I don't know

- It seems like it is not possible to disable secure_auth for the I/O thread?
- Why isn't there a more helpfull error message? (e.g.: 'error connecting to master: error 2049 (CR_SECURE_AUTH): please upgrade the password hash on the master, pre-4.1 hash is not allowed')
- Shouldn't this be documented on http://dev.mysql.com/doc/refman/5.6/en/replication-upgrade.html ?

How to repeat:
See description

Suggested fix:
- Report better error message
- Update documentation

Hello Daniël,

Thank you for the bug report.
Observed issue while replicating from 5.1.73->5.6.22.

Thanks,
Umesh

I've created Bug #74457 for the documentation part.

I can't connect through the workbench