Connection: adapt js component for custom errors

[bindlegirl]

Previously in #43593 we added support for Protected owner errors, but due to how the Error Handler was built, we hardcoded the error type into PHP and js files.

This PR is continuing the work started in #44042 where we refactored the PHP side of connection error handling so nothing has to be hardcoded. Now we are removing the protected owner errors from js files and adding support for dynamically added custom errors.

Errors are added to PHP via filter (currently limited to WoA sites), and they contain data used by JS to build error notification and actions ( message text, action type, tracking code). The Error Handler class now includes a helper function to construct a valid error_data array.

Additionally, PHP and JS can now handle custom errors with two action buttons. The secondary button is optional, but we already know we will need it for WoA pghT6q-6h-p2#comment-34.

Default connection errors should work as usual.

Closes VULCAN-184

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

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

Testing instructions:

• Create a JN site and connect Jetpack.
• Use the Beta plugin to load this PR.
• Use the Debug tool plugin to generate a connection error. Check My Jetpack and main dashboard to confirm they show up as usual, and the Reconnect button works.
• To test custom errors, it's best to fully replace the Error Handler PHP file (class-error-handler.php) in the connection package with code from this link: 38618-pb/ The test file disbles protections that prevent custom errors on nonWoA sites and adds temp test array via filter that will otherwise get used in wpcomsh.
• Edit the custom options in temp_add_protected_owner_error() to display one or two buttons and edit other parameters.
• Make sure errors show up on the dashboard, My Jetpack, and a standalone plugin page like Social.
• Alternative: test this PR together with Connection: update protected owner class #44284.

[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 or WordPress.com Site Helper), and enable the update/connection-error-refactor-js branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack update/connection-error-refactor-js

bin/jetpack-downloader test jetpack-mu-wpcom-plugin update/connection-error-refactor-js

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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  • Scheduled release: August 5, 2025
  • Code freeze: August 4, 2025

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 7 files. Only the first 5 are listed here.

File	Coverage	Δ%	Δ Uncovered
projects/js-packages/connection/hooks/use-connection-error-notice/index.jsx	0/66 (0.00%)	-25.00%	39 💔
projects/js-packages/connection/hooks/use-restore-connection/index.jsx	0/23 (0.00%)	-4.35%	1 ❤️‍🩹
projects/plugins/jetpack/_inc/client/components/notice/notice-action.jsx	9/10 (90.00%)	-10.00%	1 ❤️‍🩹
projects/packages/my-jetpack/_inc/hooks/use-notification-watcher/use-connection-errors-notice.tsx	49/50 (98.00%)	1.70%	0 💚
projects/plugins/jetpack/_inc/client/components/jetpack-notices/jetpack-connection-errors.jsx	2/20 (10.00%)	0.48%	-1 💚

Full summary · PHP report · JS report

_{If appropriate, add one of these labels to override the failing coverage check: Covered by non-unit tests Use to ignore the Code coverage requirement check when E2Es or other non-unit tests cover the code Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR I don't care about code coverage for this PR Use this label to ignore the check for insufficient code coveage.}

[sergeymitr]

Works well, as far as I can tell. Just a couple of suggestions, otherwise good to go 👍

[bindlegirl]

Thank you for reviewing this and for your suggestions @sergeymitr ! I made changes to address both recommendations.

[sergeymitr]

Works great!