Remove support for PHPUnit 10

Following up from #3531287: Remove core/recommended constraint for sebastian/diff here: with PHP10 support removed, consider restoring the core-recommended composer.json constraint on sebastian/diff.

I asked in #maintainers in Slack, and those who responded were largely unaware that we had moved to PHPUnit 11 even, but their code was still working fine, or they had had to make minimal changes. I think we should give it a few more days but it seems so far that dropping PHPUnit 10 support won't be a problem even though it is technically a BC break.

I will credit those who contributed to the discussion, but will wait a few more days for any more responses before removing the RM review tag.

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

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Only one further comment was received, agreeing that they had not noticed any difference with PHPUnit 11. Given there has been no disagreement to the plan I think it's fine to move forwards with this.

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide to find step-by-step guides for working with issues.

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide to find step-by-step guides for working with issues.

MR is pretty straightforward. At first I wondered about moving the following outside the loop, but I think it's actually more efficient this way. I guess this technically could be converted to an arrow function, but that's a person code style preference thing

    $groups = array_filter(array_unique($tmp), function (string $value): bool {
      return !str_starts_with($value, '__phpunit');
    });

I searched through the existing 11.x codebase for /phpunit.?10/, and I found a few references that might need updating:
composer/Generator/Builder/DrupalCoreRecommendedBuilder.php:

      // Remove constraint to allow sites to use PHPUnit 10 or 11, which require
      // different major versions of this package.
      // @todo Restore constraint when PHPUnit 10 is no longer supported?
      // @see https://www.drupal.org/project/drupal/issues/3537104
      'sebastian/diff',

I think this one was addressed in #8, which makes sense, but then this @todo and @see needs to be edited or removed.

core/tests/Drupal/Tests/Component/PhpStorage/FileStorageTest.php:
// PHPUnit 10 cannot expect warnings, so we have to catch them ourselves.

core/tests/Drupal/Tests/Core/Theme/Icon/IconFinderTest.php:

    // PHPUnit 10 cannot expect warnings, so we have to catch them ourselves.
    // Thanks to: Drupal\Tests\Component\PhpStorage\FileStorageTest.

core/tests/Drupal/TestTools/Extension/DeprecationBridge/DeprecationHandler.php:

 * This class is a replacement for symfony/phpunit-bridge that does not
 * support PHPUnit 10. In the future this extension might be dropped if
 * PHPUnit adds support for all deprecation management needs.

core/tests/Drupal/TestTools/Extension/DeprecationBridge/ExpectDeprecationTrait.php:

 * This trait is a replacement for symfony/phpunit-bridge that is not
 * supporting PHPUnit 10. In the future this extension might be dropped if
 * PHPUnit will support all deprecation management needs.

Also looked at the CR, which looks mostly fine, but I think this sentence is not clear.

PHPUnit 12 removes support for annotations, and in preparation issues to support it Drupal 11's PHPUnit framework may stop working properly if annotations are still in use.

I think the MR and CR look good now. Once unpostponed, should be good for RTBC unless there are significant rebase issues.

lgtm

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide to find step-by-step guides for working with issues.

I think @longwave's slack survey in #9 is the best we can do here and more than a month has passed.

Committed/pushed to 11.x and cherry-picked to 11.3.x, thanks!

Added to the release notes draft https://docs.google.com/document/d/1YOayaWh5qf6ilLpnQtD36AovZ6ii4_9ssdmi...

Release notes are mainly for site owners, but some do have phpunit tests and we don't have a long list of release notes at the moment.