Automattic
db.php deprecated use of function
There is a use of stripos() in db.php which can lead to an error:
Line 439 of db.php:
if ( false !== stripos( $query_match, $key ) ) {
As of PHP 7.3, the second parameter of stripos() cannot be an integer. I have had success overcoming this by casting the parameter as a string:
if ( false !== stripos( $query_match, (String)$key ) ) {
It would be nice to know what query lead to triggering this.. as technically, this should not really be possible (although a similar notice would be)
$key should be a table name, which is inherently a string, but it's likely false in this case as $this->get_table_from_query( $query ) probably failed..
That doesn't explain why it's an integer, rather than a boolean though..
Some code doing something like $wpdb->srtm[] = true would trigger your error though.
Unfortunately I cannot find the full query, just this snippet from my server's error log: stripos('SELECT * FROM w...', 0)
This is The Events Calendar plugin's migration process that triggers this error, causing the migration to halt indefinitely.
In a site without the HyperDB plugin, this migration performs as expected.