$collate and $charset can be undefined in wpdb::init_charset()

[robsat91]

Hello!

After updating from 5.3.1 to 4.6 i got an error:
Notice: Undefined variable: collate in /Users/robert/Nettsider/wp/ehc-wordpress/webroot/wordpress/wp-includes/wp-db.php on line 752

It seems that the reason for the error is that i did not set the constant "DB_COLLATE" in wp-config.php. This worked before, but not in 4.6.

Is there some issue with fallback values if some constants are not set maybe?

Best regards, Robert Sather.

[pento]

Thanks for the bug report, @robsat91!

You're correct, this warning will occur if DB_COLLATE isn't set - we'll get this fixed up it 4.6.1.

[robsat91]

Wow, that was fast.
Perfect, thanks mate! :)

Good job with 4.6 btw, noticing the speed increase already!

[ocean90]

Introduced in #36917.

​Another report mentions that is also happens for $charset.

[Frozzare]

Attached a possible fix that only runs determine_charset when a charset and collate isset.

[swissspidy]

The patch resolves the issue for me.

@pento Leaving final review to you. Feel free to commit afterwards.

[pento]

Thanks for the patch, @Frozzare!

I think a better solution would be to set $charset and $collate to empty strings at the start of ::init_charset(). ::determine_charset() should be called, even when $collate is not set, as the collation can change based on the charset. It doesn't really matter either way if the method is called when $charset is empty, I'm inclined to call it just to not increase code complexity.

Also, $this->charset and $this->collate need to be set, even when the local vars are empty, or similar warnings will occur in ::set_charset().

Finally, a note to committers: please don't commit any patches on this ticket without my review - #37689 may be related, which I'm currently investigating. The outcome of that ticket may have an effect on the best solution for this ticket.

[Frozzare]

@pento thanks for the feedback! Attached a new patch with empty string variables.

[SergeyBiryukov]

#37815 was marked as a duplicate.

[pento]

In 38439:

Database: Ensure that variables are defined correctly.

There were some cases where some local variables in wpdb::init_charset() could be undefined when they were used.

Props Frozzare.
Fixes #37683 for trunk.

[pento]

In 38440:

Database: Ensure that variables are defined correctly.

There were some cases where some local variables in wpdb::init_charset() could be undefined when they were used.

Merge of [38439] to the 4.6 branch.

Props Frozzare.
Fixes #37683.