Some composer dependencies fail to install with composer v2.0.0

[imath]

It only happens for PHP 5.6 jobs.

For now, I will include a quick fix to .travis.yml to rollback to composer v1.10.16.

But I believe we should look into it more deeply during next release.

[imath]

In 12766:

Build Tools: Make sure to use composer v1.10.16

This is a quick fix to avoid some composer dependencies to fail to install with composer v2.0.0 for PHP 5.6 jobs.

See #8381

[imath]

In 12786:

Build Tools: Make sure to use composer v1.10.16

This is a quick fix to avoid some composer dependencies to fail to install with composer v2.0.0 for PHP 5.6 jobs.

See #8381 (6.0 branch)

[imath]

In ​8381.patch, I'm making sure all dependencies are installed by updating them to their compatible versions with composer v2.0+. I'm also taking this opportunity to add the phpunit/phpunit dependency to be able to run PHP Unit tests with version 8.0 of PHP.

To test PHP 8.0 using @wordpress/env, you then simply need to run:

1. composer update
2. export WP_ENV_PHP_VERSION="8.0"
3. npm run wp-env start
4. npm run test-php:composer or npm run test-php-multisite:composer

We should then be able to use @wordpress/env to create a first GitHub action to test PHP 8.0 see #8421

[imath]

I believe 8381.2.patch is our way forward with Composer v2. The main difference with first patch is that it uses the PHPUnit composer version for all tests. It allows us to test PHP 7.x and PHP 8.0. It will also fix #8420

I'm going to commit it asap.

[imath]

In 12852:

Update Composer dependencies to match its v2 requirements

• Updates composer/installers to 1.10
• Updates phpcompatibility/phpcompatibility-wp to 2.1
• Updates dealerdirect/phpcodesniffer-composer-installer to 0.7.1
• Updates wp-phpunit/wp-phpunit to latest
• Adds a dependency to phpunit/phpunit v7.5+ to be able to run PHP 8.0 unit tests using @wordpress/env.

Props slaFFik

Fixes #8381
Fixes #8420

[imath]

It should fix Travis fails

[imath]

I'm reopening this ticket as Travis doesn't like too much the changes I've introduced in .2.patch. I believe .3.patch should satisfy Travis & @wordpress/env. I still need to test @wordpress/env to check it doesn't introduce regressions.

[imath]

In 12853:

Use the PHPUnit Composer dependency to run Travis tests

• Adds version 5.7 to the WordPress matrix
• Only run tests about PHP 5.6 with WP 4.9

See #8381

[imath]

In 12854:

Downgrade the PHPUnit Composer deps when running Travis PHP 5.6 tests

This move is needed to still be able to test BuddyPress against PHP 5.6 in Travis. This commit also adds a PHP 7.4 job.

Fixes #8381

[imath]

In 12855:

Travis : only test BuddyPress against WP < 5.1 with PHP 5.6

PHPUnit ^{7 WordPress support was introduced in ​WordPress 5.1. For older versions of WordPress (4.9 & 5.0), let's use the specific before_script we're using to downgrade Composer PHPUnit dependency to its 5.7.27 version to be able to test PHP 5.6.}

See #8381