get_user_by can return wrong user info

[hberberoglu]

I am using memcached object cache dropin (I use ​https://tr.wordpress.org/plugins/memcached/) and there is two user record on wp_users table; one user's user_login is 'AlbertEinstein' other one's is 'Albert Einstein'. So there is two different user.

But these codes below are returning always same user's info; AlbertEinstein's info.

$user_data = get_user_by('login', 'Albert Einstein');

$user_data = get_user_by('login', 'AlbertEinstein');

It happens because of memcached protocol;

For installs that use the memcache/memcached object-cache drop-in (and possibly others), the resulting wp_cache_get always returns false since a memcached key "... must not include control characters or whitespace." (per ​https://github.com/memcached/memcached/blob/master/doc/protocol.txt)

(this copied from #39034)

[ocean90]

This is actually a bug in the drop-in caused by this line:
return preg_replace('/\s+/', '', WP_CACHE_KEY_SALT . "$prefix$group:$key"); .

Using a placeholder in cache keys rather than simply stripping out spaces would solve this.

[hberberoglu]

@ocean90 thanks for fast response. I agree with you and to solve this I'll do a code change on drop-in side. I do not know how WordPress's approach is in such cases.

If you say; the drop-in should solve this, then okay, you can close this ticket.

If you say; we can make changes on our code so that our users do not experience this problem, then keep this ticket open.

[pbearne]

I think this has been fixed

Can we close this?