Subscriptions: Prevent warning when $post global is malformed

[tbradsha]

Proposed changes

We're getting some of these:

PHP Warning: Attempt to read property "ID" on array in /wordpress/plugins/jetpack/15.7/modules/subscriptions/subscribe-modal/class-jetpack-subscribe-modal.php on line 239

Because $post is a global, third-party code can and does sometimes modify it. This PR ensures it's a WP_Post before trying to use it.

Related product discussion/links

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

Testing instructions

Looking at the code is probably the easiest option.

[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 WoA dev 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 (Jetpack), and enable the fix/subscriptions/address_warnings_in_the_wild branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack fix/subscriptions/address_warnings_in_the_wild

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]

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen as soon as you deploy your changes after merging this PR (PCYsg-Jjm-p2).
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  • Scheduled release: May 5, 2026
  • Code freeze: May 4, 2026

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[anomiex]

Seems reasonable to me. I don't know if there's a more reliable way to get the post than the $post global.

[jp-launch-control]

Code Coverage Summary

Coverage changed in 1 file.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/jetpack/modules/subscriptions/subscribe-modal/class-jetpack-subscribe-modal.php	0/87 (0.00%)	0.00%	2 ❤️‍🩹

Full summary · PHP report · JS report