Database migration didn't work properly

[carlomanf]

Describe the bug
The database migration introduced in #27910 did not erase all of the data it was designed to erase.

• Auto-drafts are correctly erased but their term relationships didn't get erased. In other words, you end up with "orphan" entries in the term relationships table.

• The _wp_file_based term didn't get erased.

• The gutenberg_last_synchronize_theme_template_checks option didn't get erased.

• The gutenberg_last_synchronize_theme_template-part_checks option didn't get erased.

Expected behavior
Either the migration needs to be complete, or don't bother including a migration at all.

Editor version (please complete the following information):

• WordPress version: 5.6
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? plugin
• If the Gutenberg plugin is installed, which version is it? 13 Jan 2021 commit on master branch

[talldan]

Pinging @youknowriad as the author of #27910 for feedback.

[youknowriad]

I assumed the "delete_term" does remove the relationships but it seems that it doesn't. and I forgot about the options.

[carlomanf]

I assumed the "delete_term" does remove the relationships but it seems that it doesn't.

I think it is meant to. I can't work out why it doesn't here, but I'd guess it's the auto-draft status causing trouble again.

[youknowriad]

Do you have an idea on how we could overcome that?

[carlomanf]

If you were desperate you could always write out the queries through $wpdb, but identifying the cause of the migration failure might uncover a better solution.

[ockham]

wp_delete_object_term_relationships looks promising 🤔 I'll see if that's supposed to be automatically run by wp_delete_term (and under what circumstances), or if it always needs to be manually run.

[ockham]

Hmm, while wp_delete_term doesn't seem to invoke wp_delete_object_term_relationships, it does look like it should remove term relationships no less: https://core.trac.wordpress.org/browser/trunk/src/wp-includes/taxonomy.php?rev=49947#L1935

[carlomanf]

Hmm, while wp_delete_term doesn't seem to invoke wp_delete_object_term_relationships, it does look like it should remove term relationships no less: https://core.trac.wordpress.org/browser/trunk/src/wp-includes/taxonomy.php?rev=49947#L1935

It's more complicated than that. The call to wp_delete_term actually had no effect at all, so it didn't even delete the term, let alone the relationships. wp_delete_post was also meant to delete the relationships for the given post, and didn't.

It might be wise to write some unit tests for this, if it's possible to do so.

[ockham]

I might have a promising lead 😬

Compare https://github.com/WordPress/gutenberg/pull/27910/files#diff-d8826d0f767301135f001ac1a09905bf32198b6604bf6a3fdf15799ea4c7ea48L119 to https://github.com/WordPress/gutenberg/pull/27910/files#diff-25417a675fde0cd7653118033809d3692e62da2788c4ac63d2f8d42eca4a29a8R52

We're setting wp_theme, but attempting to delete wp-theme.

Maybe it's as simple as that 🤞

[ockham]

The other problem seems to be that get_term_by doesn't seem to find any wp_theme terms. The reason for this might be that we're attempting to do so from the _gutenberg_migrate_database method, which is hooked into plugins_loaded. However, the wp_theme taxonomy is registered in gutenberg_register_wp_theme_taxonomy, which is hooked into init. And init comes after plugins_loaded.