Fatal Error: _preload_old_requests_classes_and_interfaces() when updating from WordPress older than 4.6

[afragen]

During the 6.2-beta1 release party I got the following error (see image).

I'm using a local test site just for the release party. I was on 6.1.1 and used Core Rollback to revert to 4.0.38. I have WordPress Beta Tester set to 'Bleeding Edge' and 'Beta/RC'.

I initially tried 4.038, 4.1.37 both initially failed. The I updated from 5.9.5 and worked my way back down the releases from each major. I retried the first 2 again and they passed.

Core Rollback and WordPress Beta Tester at current releases used.

[costdev]

Testing Instructions

These steps define how to reproduce the issue, and indicate the expected behavior.

Steps to Reproduce

1. Use PHP 5.6.
2. Set up a 6.1.1 site.
3. Enable WP_DEBUG, WP_DEBUG_LOG and WP_DEBUG_DISPLAY in wp-config.php.
4. Install and activate the Core Rollback and WordPress Beta Tester plugins.
5. Navigate to Tools > Rollback Core.
6. Select 4.0.38 from the <select> element and click Rollback.
7. Navigate to Dashboard > Updates and click Re-install 4.0.38.
8. Navigate to Tools > Beta Testing.
9. Select Bleeding Edge and Beta/RC only. Click Save Changes.
10. 🐞 Navigate to Dashboard > Updates and click Update now.

Expected Results

When testing a patch to validate it works as expected:

• ✅ There is no fatal error.

When reproducing a bug:

• ❌ There is a fatal error:

Fatal error:
Class 'Requests_Exception' not found in /site/path/wp-includes/Requests/Exception/HTTP.php on line 13

[costdev]

Requests was introduced in WordPress 4.6, see #33055.

• GitHub - WordPress 4.5: ​https://github.com/WordPress/wordpress-develop/tree/4.5/src/wp-includes
• GitHub - WordPress 4.6: ​https://github.com/WordPress/wordpress-develop/tree/4.6/src/wp-includes

Looks like we need a minimum version check in _preload_old_requests_classes_and_interfaces().

Preparing a patch now.

The Requests library was introduced in WordPress 4.6.

Attempting to preload the Requests 1.x classes/interfaces in earlier versions of WordPress
causes a fatal error.

This skips preloading if the website previously used a WordPress version earlier than 4.6.

Trac ticket: https://core.trac.wordpress.org/ticket/57662

[ironprogrammer]

Test Report

Patch tested: ​https://github.com/WordPress/wordpress-develop/pull/4029

To test the patch, refer to ​these custom update package test instructions.

Environment

• Hardware: iMac
• OS: macOS 12.6.2
• Browser: Safari 16.2
• Server: Apache/2.4.55 (Unix) PHP/5.6.40
• PHP: 5.6.40
• WordPress: 6.1.1
• Theme: twentytwentyone v1.6
• Active Plugins:
  • core-rollback v1.3.4
  • wordpress-beta-tester v3.2.7
  • fake-wordpress-update (see the test instructions above)

Actual Results

When reproducing a bug:

• "Fatal error: Class 'Requests_Exception'" occurred when attempting to update.

When testing a patch to validate it works as expected:

• Using a patched build package, the update to 6.2-beta1 succeeded without error.

Additional Notes

• In test Step 2, ensure that a classic theme is active. I was unable to roll back past 5.9 with a block theme active.
• For clarity, the fatal error that occurred prevented the update, but did leave the site in a usable state (i.e. I was able to then test the patched build).

[antonvlasenko]

Test Report

Patch tested: ​https://github.com/WordPress/wordpress-develop/pull/4029

Test instructions provided by @ironprogrammer: ​https://gist.github.com/ironprogrammer/1aaff6f60b263c1842e3584365729ffc

Environment

• Hardware: Mac mini M1
• wp-env
• OS: macOS 13.1
• PHP: 5.6.39
• WordPress: 6.2-beta1
• Browser: Safari 16.2
• Theme: Twenty Twelve
• Active Plugins:
  • core-rollback v1.3.4
  • wordpress-beta-tester v3.2.7
  • fake-wordpress-update (see the test instructions above)

Actual Results

When reproducing a bug:

• ❌ "Fatal error: Class 'Requests_Exception'" occurred when attempting to update.

When testing a patch to validate it works as expected:

• ✅ No errors when updating to the patched version of WordPress.

Notes

If you are testing the patch on wp-env:

1. You may need to use this workaround to install WordPress on PHP 5.6: ​https://github.com/WordPress/gutenberg/issues/40745#issuecomment-1422471660
2. Also, when creating a custom WordPress package, you will need to upload it to a server accessible from the Internet (I used GitHub). Otherwise, WordPress will not see it (due to wp-env).

[hellofromTonya]

Currently reviewing for commit.

[hellofromTonya]

​https://github.com/WordPress/wordpress-develop/pull/4029

• 2 Test Reports ✅
• Resolves the reported issue ✅
• Bails out immediately to skip Requests preloading logic ✅

Ready for commit 👍

[hellofromTonya]

Prepping commit now.

[hellofromTonya]

In 55296:

Upgrade/Install: Skip preloading Requests for WordPress versions before 4.6.

Skip preloading Requests files in _preload_old_requests_classes_and_interfaces() when updating from a WordPress version older than 4.6.

Why?

Requests library was first introduced into WordPress 4.6 via #33055 / [37428]. If a user is upgrading from a version older than 4.6, this changeset prevents the Requests preloading to prevent a fatal error of attempting to load files that do not exist in their current WordPress version.

Follow-up to [54997], [37428].

Props afragen, costdev, ironprogrammer, antonvlasenko.
Fixes #57662.

Committed via https://core.trac.wordpress.org/changeset/55296.

[hellofromTonya]

Renamed for the root cause.

[peterwilsoncc]

For upgrades from 4.5 and earlier, does the previous library need to be pre-loaded in a similar fashion?

I suspect the answer is no but I'd sure feel silly if I didn't ask and it became a problem.

[afragen]

Since Requests was first introduced in 4.6, it's not necessary to pre-load anything prior to that. At least that's my understanding.