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wordpress/wp-includes
Sergey Biryukov d89482b22d Query: Cast the meta key to BINARY for case-sensitive key comparisons in WP_Meta_Query.
This addresses an error on MySQL 8.0.22 or later:
{{{
Character set 'utf8mb4_unicode_520_ci' cannot be used in conjunction with 'binary' in call to regexp_like
}}}

From the [https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-22.html MySQL 8.0.22 changelog]:
> Regular expression functions such as `REGEXP_LIKE()` yielded inconsistent results with binary string arguments. These functions now reject binary strings with an error. ([https://bugs.mysql.com/bug.php?id=98951 Bug #98951], [https://bugs.mysql.com/bug.php?id=98950 Bug #98950])

WordPress meta queries use the `BINARY` data type for case-sensitive meta key comparisons using regular expressions. By explicitly casting the meta key to `BINARY`, we can make sure the values being compared use the same character set and produce consistent results.

The change is covered by existing meta query unit tests: three tests which previously failed on MySQL 8.0.22 or later now pass.

References:
* [https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-22.html MySQL 8.0.22 changelog]
* [https://bugs.mysql.com/bug.php?id=104387 Bug #104387 CHARACTER_SET_MISMATCH issue with regex comparisons]

Follow-up to [46188].

Fixes #51740.
Built from https://develop.svn.wordpress.org/trunk@53901


git-svn-id: http://core.svn.wordpress.org/trunk@53460 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2022-08-17 14:00:13 +00:00
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