Connection: work around a WP user caching bug

[sergeymitr]

Proposed changes:

WP bug #62003 leads to inconsistent format of cached user data in certain circumstances.
It happens if only one field gets fetched from the database, so we add ID to work around the issue.

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?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

https://core.trac.wordpress.org/ticket/62003
p1731513241019199-slack-C05PV073SG3
p1725570377885549-slack-C7YPW6K40

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

No.

Testing instructions:

First try to reproduce the issue on trunk.

1. Install and activate an object cache plugin (e.g. Docket Cache).
2. Add this code snipped to your site:

add_action( 'plugins_loaded', function() {
	get_users( array( 'role' => 'administrator', 'orderby' => 'user_registered', 'fields'  => 'user_registered', 'number'  => 1 ) );
} );

3. Connect Jetpack in site-only mode.
4. Load Jetpack Dashboard.
5. Clean the cache and remove the transient:

wp cache flush
wp transient delete jetpack_assumed_site_creation_date

6. Reload Jetpack Dashboard and confirm you see the PHP warning in your debug.log:

PHP Warning:  Attempt to read property "user_registered" on string in ...

7. Clean the cache and remove the transient (step 5).
8. Checkout the branch, reload Jetpack Dashboard. Confirm you no longer see the warning.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the fix/connection-dotorg-user-cache-bug branch.

  • For jetpack-mu-wpcom changes, also add define( 'JETPACK_MU_WPCOM_LOAD_VIA_BETA_PLUGIN', true ); to your wp-config.php file.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack fix/connection-dotorg-user-cache-bug
  

  bin/jetpack-downloader test jetpack-mu-wpcom-plugin fix/connection-dotorg-user-cache-bug
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

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[coder-karen]

This tests well, thanks!

As an aside I'm curious - is the goal with this PR just to create a temporary workaround until and if the core bug gets fixed? Should we add a @todo or similar in order to have a reminder to come back to this in the future?

[sergeymitr]

Thanks @coder-karen!
The code will probably be there for quite a while to support older WP versions.
Good point about the @todo tag, I'll add that.