id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc
23085,Calling $wpdb->query() when no connection exists causes mysql_error() to throw an error,mbijon,,"In the query() method of wp-db.php, the mysql_error() expects that if a parameter is passed to it then it should be a valid link identifier.

*May need feedback or added testing* ...this error may be specific to transactions, which is why it hasn't been noticed before. Unit tests do use transations and I only get these errors when ROLLBACK is called during specific unit tests that don't modify the DB state. A simple transaction opened & rolled back in the Debug Bar Console is not triggering this for me.

Unit test failure examples:

'''Test: test_is_image_positive'''

{{{
mysql_error() expects parameter 1 to be resource, integer given
Execution time: 0.02507209777832s
Stack Trace:
Array
(
    [0] => Array
        (
            [file] => C:\xampp\htdocs\wpnew\wp-includes\wp-db.php
            [line] => 1202
            [function] => mysql_error
            [args] => Array
                (
                    [0] => 0
                )

        )

    [1] => Array
        (
            [file] => C:\xampp\htdocs\wp_test_svn\includes\testcase.php
            [line] => 25
            [function] => query
            [class] => wpdb
            [type] => ->
            [args] => Array
                (
                    [0] => ROLLBACK
                )

        )

)
}}}

'''Test: test_is_image_negative'''

{{{
mysql_error() expects parameter 1 to be resource, integer given
Execution time: 0.02237606048584s
Stack Trace:
Array
(
    [0] => Array
        (
            [file] => C:\xampp\htdocs\wpnew\wp-includes\wp-db.php
            [line] => 1202
            [function] => mysql_error
            [args] => Array
                (
                    [0] => 0
                )

        )

    [1] => Array
        (
            [file] => C:\xampp\htdocs\wp_test_svn\includes\testcase.php
            [line] => 25
            [function] => query
            [class] => wpdb
            [type] => ->
            [args] => Array
                (
                    [0] => ROLLBACK
                )

        )

)
}}}

I don't think we should attempt {{{if ( $this->last_error = mysql_error() )}}}. That is because when mysql_error() is called without a link identifier then the most recent connection to MySQL is referenced. On a busy server this may not be the same connection as our page or transaction originally used. See #3544 for history/details.",defect (bug),new,normal,Awaiting Review,Database,3.5,minor,,dev-feedback has-patch 2nd-opinion,kurtpayne