Issue #3284420 by longwave, Gábor Hojtsy, Spokje: Remove Composer 1 specific code paths from Drupal 10

(cherry picked from commit 6c6f6a3f31d7df657c32d634c9fa8fdf4723ae9a)

Author: catch

AllowedPackages.php

@@ -3,7 +3,6 @@
 namespace Drupal\Composer\Plugin\Scaffold;
 
 use Composer\Composer;
-use Composer\DependencyResolver\Operation\OperationInterface;
 use Composer\Installer\PackageEvent;
 use Composer\IO\IOInterface;
 use Composer\Package\PackageInterface;
@@ -101,8 +100,7 @@ public function event(PackageEvent $event) {
     // which of the newly-installed packages have scaffold operations, and
     // whether or not they are allowed to scaffold by the allowed-packages
     // option in the root-level composer.json file.
-    $operationType = $this->getOperationType($operation);
-    $package = $operationType === 'update' ? $operation->getTargetPackage() : $operation->getPackage();
+    $package = $operation->getOperationType() === 'update' ? $operation->getTargetPackage() : $operation->getPackage();
     if (ScaffoldOptions::hasOptions($package->getExtra())) {
       $this->newPackages[$package->getName()] = $package;
     }
@@ -181,26 +179,6 @@ protected function evaluateNewPackages(array $allowed_packages) {
     return $allowed_packages;
   }
 
-  /**
-   * Determine the type of the provided operation.
-   *
-   * Adjusts API used for Composer 1 or Composer 2.
-   *
-   * @param \Composer\DependencyResolver\Operation\OperationInterface $operation
-   *   The operation object.
-   *
-   * @return string
-   *   The operation type.
-   */
-  protected function getOperationType(OperationInterface $operation) {
-    // Use Composer 2 method.
-    if (method_exists($operation, 'getOperationType')) {
-      return $operation->getOperationType();
-    }
-    // Fallback to Composer 1 method.
-    return $operation->getJobType();
-  }
-
   /**
    * Retrieves a package from the current composer process.
    *

composer.json

@@ -6,7 +6,7 @@
   "homepage": "https://www.drupal.org/project/drupal",
   "license": "GPL-2.0-or-later",
   "require": {
-    "composer-plugin-api": "^1 || ^2",
+    "composer-plugin-api": "^2",
     "php": ">=7.3.0"
   },
   "conflict": {