Composer v2 compatibility

JeppeKnockaert commented 4 years ago

Q	A
Branch	master for features and deprecations
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Documented?	yes
Fixed tickets	#756

This pull request adds support for Composer v2. I've also added the version of composer to the test matrix, so both versions are tested.

Wrong namespaces don't get autoloaded anymore in Composer v2, so I fixed that as well.
Paratest has not created a version supporting composer v2 yet, this is why I included the dev requirement
friendsofphp/php-cs-fixer has an open PR for composer v2 (https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/4935), but doesn't even seem to be needed anymore in the dev requirements, so I left it out. The alternative would be to include a phar version of php-cs-fixer for Travis.
hirak/prestissimo should not be installed anymore for composer v2 (this is now built-in), see https://github.com/hirak/prestissimo/issues/218
I don't think we need to use deactivate/uninstall (for now), because cleanup is already done by using events. Maybe things can be cleaned up / optimized after composer v1 has been dropped.

veewee commented 4 years ago

Thanks for the PR! It looks really nice.

The error is related to a broken openssl on appveyor, will have to take a look at why it fails before I merge it in.

JeppeKnockaert commented 4 years ago

Thank you @veewee. It seems every recent PR has this issue. I believe it is linked to this PHP issue, which was fixed in 7.4.6RC1 according to the comments in that issue (https://bugs.php.net/bug.php?id=79589).

veewee commented 4 years ago

yeah .. maybe best to hardcode it to a previous 7.4 version for now?

veewee commented 4 years ago

Thanks again!

phpro / grumphp

Composer v2 compatibility #768