Fatal error: Interface 'Composer\Plugin\Capability\CommandProvider' not found

[DieterHolvoet]

I'm getting an error during composer install of drupal-composer/drupal-scaffold on version 2.5.2:

Fatal error: Interface 'Composer\Plugin\Capability\CommandProvider' not found in <redacted>/vendor/drupal-composer/drupal-scaffold/src/CommandProvider.php on line 10

[greg-1-anderson]

What version of Composer are you running? Try composer selfupdate and see if it starts working.

[DieterHolvoet]

Composer version @package_branch_alias_version@ (1.0.0-beta2) 2016-03-27 16:00:34

Obviously we should update, but isn't it possible for you to indicate the required version of composer needed for the package to function?

[greg-1-anderson]

I thought there was a check for the Composer version in there somewhere. Perhaps for sufficiently ancient versions of Composer, the failure happens before the check. I didn't attempt to reproduce though.

[webflo]

1.0.0-beta2 is a an ancient version. You you try to install the last composer release? Thanks!

[DieterHolvoet]

Yeah, that version of composer is still running on our deployment server, we're going to update it. Thanks!