Pre-existing termmeta table not converted to utf8mb4 collation

[dboulet]

WordPress 4.4 introduces the termmeta database table, and also attempts to be accomodating of situations where this table was previously created—for example, by a plugin. The upgrade process properly updates the index on the pre-existing table to facilitate the move to utf8mb4, but doesn’t actually attempt to convert the table to the new collation. If the table was created prior to version 4.2, it will retain the old collation.

[boonebgorges]

Thanks very much for the ticket and the patch, dboulet.

Your fix looks right to me, but I'd like to get the AOK from Monsieur Pento before going with it.

[pento]

Yep, I'm cool with this patch.

Probably need to bump the $db_version, too, for those lucky people running trunk on their sites.

[dboulet]

Thank you boonebgorges and pento, I’ve attached a new patch.

[SergeyBiryukov]

In 34978:

After [34529], if a compatible termmeta table is found on database upgrade, convert it to utf8mb4 collation.

Props dboulet.
Fixes #34224.