Fix site title block block style missing

[fullofcaffeine]

Fixes the issue reported here: p9F6qB-afB-p2
Related Issue: #26224

Discussion: p1662734279580389-slack-C01DF571R5Y

Changes proposed in this Pull Request:

Set the Automattic\Jetpack\Fonts\Introspectors\Global_Styles::enqueue_global_styles_fonts callback priority in the init hook to 22 to prevent it from causing style issues with sites that have Gutenberg > 13.5 activated.

The default priority meant that this callback ran before this one in Gutenberg, and for some reason (probably CSS specificity?) it was affecting the styles/fonts set by the Gutenberg callback. See the details in the linked P2 page above.

This seems to happen only in org sites connected to JP and with the JP plugin installed. This includes WoA. Simple sites are not affected.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

AT

1. Install the TT2 theme, make the site public and view the main page of the site in the frontend;
2. Install Gutenberg 14.0.3
3. Verify that the issue in p9F6qB-afB-p2 happens;
4. Install the Jetpack beta tester plugin and install the plugin from this branch;
5. Verify that the issue in p9F6qB-afB-p2 doesn't happen and that the title looks as expected;

vanilla JP (jurassic.ninja)

This bug doesn't manifest in plain JP+org sites, but we should still sanity-check the changes:

1. Install the TT2 theme, make the site public and view the main page of the site in the frontend;
2. Install Gutenberg 14.0.3
3. Install the Jetpack beta tester plugin and install the plugin from this branch;
4. Verify that the issue in p9F6qB-afB-p2 doesn't happen and that the title looks as expected;

Simple sites

This bug doesn't manifest in simple sites, but we should still sanity-check the changes:

1. Install the TT2 theme, make the site public and view the main page of the site in the frontend;
2. In you sandbox, run bin/jetpack-downloader test jetpack fix/site-title-block-block-style-missing to install the JP plugin from this branch;
3. Verify that the issue in p9F6qB-afB-p2 doesn't happen and that the title looks as expected;

[github-actions]

Are you an Automattician? You can now test your Pull Request on WordPress.com. On your sandbox, run bin/jetpack-downloader test jetpack fix/site-title-block-block-style-missing to get started. More details: p9dueE-5Nn-p2

[github-actions]

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[fullofcaffeine]

I couldn't reproduce the issue in an org+JP site either (using jurassic.ninja). I think it has to do with the fact enqueue_global_styles_fonts didn't specify a priority, maybe? I'm not sure; and I don't think it's worth spending more time as the fix seems to work fine on AT and doesn't seem to affect simple and JP+org sites.

[jeyip]

Testing

Requirements

Atomic

• Site title font styles are not stripped in frontend
• Frontend renders as expected
• Custom google fonts load as expected in editor + frontend

Self-hosted

• Frontend renders as expected
• Custom google fonts load as expected in editor + frontend

Simple

• Frontend renders as expected
• Custom google fonts load as expected in editor + frontend

Browsers

• Chrome

Note for other testers -- when testing google fonts on simple sites with this PR's changes, it takes a few moments for the cached fonts to invalidate. After a bit, the proper font should be displayed

[jeyip]

I don't see any problems with updating the priority. From what I can tell, the frontend for all environments continues to load google fonts properly. 🚢

Thanks for drafting this 🙏

[anomiex]

Fixes the issue reported here: p9F6qB-afB-p2

This works around the problem for sites where Jetpack is the trigger for the bug, but the underlying cause seems to be something in Gutenberg 13.5.0+. Well, maybe. It may be that the resolution there should be to document that things calling the things we're calling should run at priority 21 or later.

probably CSS specificity?

No, not specificity. Somehow Gutenberg 13.5.0+ fails to output the relevant styles at all.

This seems to happen only in org sites connected to JP and with the JP plugin installed. This includes WoA.

It can happen in sites without Jetpack installed at all, if something else calls gutenberg_get_global_styles() at the wrong time during init. See #26224 (comment).

[anomiex]

Investigated to find the real cause of the issue, and suggested an update to the comment accordingly.

[samiff]

This seemed to work ok on my WoA site with TT2 & Gutenberg v14.0.2, I was able to see the .wp-block-site-title style correctly applied after patching with this branch.