Bug #67740 setting slow_query_log_file to a value without a "=" sign enables general log
Submitted: 28 Nov 2012 12:09 Modified: 20 Mar 2013 2:10
Reporter: Miguel Angel Nieto Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Logging Severity:S3 (Non-critical)
Version:5.1, 5.5, 5.5.30, 5.7.1 OS:Any
Assigned to: CPU Architecture:Any
Triage: Needs Triage: D2 (Serious)

[28 Nov 2012 12:09] Miguel Angel Nieto
Description:
Tested on the latest 5.5 and 5.1. If you add the following to my.cnf:

slow_query_log_file /var/lib/mysql/slow.log

MySQL starts without an error and enables the general query log.

How to repeat:
Add the following to my.cnf:

slow_query_log = 1
slow_query_log_file /var/lib/mysql/slow.log

and then run:

show variables like '%general_log%';

Suggested fix:
It should show an error/warning message but not enable general query log.
[28 Nov 2012 18:19] Sveta Smirnova
Thank you for the report.

Verified as described.
[28 Nov 2012 18:20] Sveta Smirnova
Version 5.7.1 does not start, but fails with:

2012-11-28 20:19:30 0 [ERROR] ./bin/mysqld: ambiguous option '--log' (log-bin, log_slave_updates)
2012-11-28 20:19:30 0 [ERROR] Aborting

2012-11-28 20:19:30 0 [Note] Binlog end
[20 Mar 2013 2:10] Paul Dubois
Noted in 5.7.2 changelogs.

In option files, the server could misinterpret option settings if the
value was given after the option name with no = sign in between.