Bug #13717 sql_print_warning dumps unsilenceable warnings to STDERR under libmysqld

Description:
Hello,

looking at the source (log.cc), sql_print_warning() calls vprint_msg_to_log() which calls print_buffer_to_file() which uses fprintf() to print directly to stderr.

When using libmysqld, this results in unsilenceable warnings being printed over the output of the program using libmysqld, which would be weird to the end user.

How to repeat:
run a libmysqld application without a mysql table and you will get a "[Warning] Can't open and lock time zone table: Table 'mysql.time_zone_leap_second' doesn't exist trying to live without them" message on stderr which can not be suppressed.

Suggested fix:
Provide an option to silence warnings when used under libmysqld.

In the long term, maybe provide those warnings in a stack from which the application can pop and process them at will, the way SHOW WARNINGS sql command works.

Thanks for your bug report

Moving this bug to the libmysqld category, where it belongs.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/9881

ChangeSet@1.2532, 2006-08-01 15:18:21+05:00, holyfoot@mysql.com +1 -0
  bug #13717 embedded library dumps warnings on STDERR directly
  
  Here i just disabled STDERR warnings in embedded server
  Later we should get more defined about logs in the embedded server

The patch looks ok.

Please consider adding a worklog item to make
embedded server honor --log-error.

Patch looks okay to push to me.

pushed to 5.0.25 main this morning.  not  yet in 5.1 tree

now pushed to 5.1.12

Noted in 4.1.22, 5.0.25, 5.1.12 changelogs.

libmysqld produced some warnings to stderr which could not be
silenced. These warnings now are suppressed.

Unfortunately it appears that the patch blocks legitimate error messages, not just warnings. Please see:

http://bugs.mysql.com/bug.php?id=25097