Boost Page Cache: make module off when Endurance Page Cache is on

[jeherve]

Fixes HOG-96

Proposed changes:

When a site already uses the Endurance Page Cache service, and that service is active on the site, we should not offer the option to turn on Boost's page cache.

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

• p1746778589553919-slack-C016BBAFHHS

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

• No

Testing instructions:

Note

Test this on a site using Endurance page cache. See HOG-96.
Alternatively, you can set add_filter( 'jetpack_boost_compatibility_has_cache', '__return_true' ); in your testing environment to mock things.

• Go to Settings > General
• Scroll down to the bottom of the page
• Change settings to activate or deactivate page cache
• Go to Jetpack > Boost
• The Page Cache module availability should be updated accordingly. A notice should be displayed

[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:

• ✅ Include a description of your PR changes.
  
• ✅ Add a "[Status]" label (In Progress, Needs Review, ...).
  
• ✅ Add a "[Type]" label (Bug, Enhancement, Janitorial, Task).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
2. Make sure to test your changes on all platforms that it applies to. You're responsible for the quality of the code you ship.
3. You can use GitHub's Reviewers functionality to request a review.
4. When it's reviewed and merged, you will be pinged in Slack to deploy the changes to WordPress.com simple once the build is done.

If you have questions about anything, reach out in #jetpack-developers for guidance!

---

Boost plugin:

No scheduled milestone found for this plugin.

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

[jp-launch-control]

Code Coverage Summary

Coverage changed in 2 files.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/boost/app/modules/optimizations/page-cache/class-page-cache.php	2/37 (5.41%)	-0.31%	2 ❤️‍🩹
projects/plugins/boost/app/admin/class-config.php	37/37 (100.00%)	0.00%	0 💚

2 files are newly checked for coverage.

File	Coverage
projects/plugins/boost/app/assets/src/js/lib/utils/caching.ts	0/2 (0.00%) 💔
projects/plugins/boost/app/lib/class-cache-compatibility.php	6/7 (85.71%) 💚

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.}

[dilirity]

Awesome work, thanks for taking care of this and including tests!

It's ready for a merge.

When I saw the notice that Page Cache is unavailable, I recalled a conversation about users on WoA being unable to activate Boost's cache. As a result, we ended up updating the UI to this:

I wonder if it makes sense to update the current notice to be in the same style, but say "your hosting" instead of "WordPress.com". If we do, we can do it in a follow up. I just wanted your thoughts on this.