First observed in this CI build:
> composer phpcs composer/installers contains a Composer plugin which is blocked by your allow-plugins config. You may add it to the list if you consider it safe. See https://getcomposer.org/allow-plugins You can run "composer config --no-plugins allow-plugins.composer/installers [true|false]" to enable it (true) or keep it disabled and suppress this warning (false) dealerdirect/phpcodesniffer-composer-installer contains a Composer plugin which is blocked by your allow-plugins config. You may add it to the list if you consider it safe. See https://getcomposer.org/allow-plugins You can run "composer config --no-plugins allow-plugins.dealerdirect/phpcodesniffer-composer-installer [true|false]" to enable it (true) or keep it disabled and suppress this warning (false) > phpcs -p -s ERROR: Referenced sniff "SlevomatCodingStandard.TypeHints.ReturnTypeHintSpacing" does not exist Run "phpcs --help" for usage information Script phpcs -p -s handling the phpcs event returned with error code 3 Script composer phpcs handling the test event returned with error code 3
Somehow, the slevomat/coding-standard package doesn’t get installed quite properly (though it is in the composer install output), and then PHPCS crashes when it can’t load the sniff referenced in the PHPCS file. According to the quoted composer output, this seems to be due to the changed default of the allow-plugins config, where composer decided it was a great idea to have the default behavior change based on the calendar date, even if you install the same software version where everything worked previously. (See also T298283.)
