Deprecate Composer 1

Signed-off-by: Alexander M. Turek <me@derrabus.de>

Author: derrabus

ContainerBuilder.php

@@ -1484,11 +1484,18 @@ public function log(CompilerPassInterface $pass, string $message)
      */
     final public static function willBeAvailable(string $package, string $class, array $parentPackages): bool
     {
+        $skipDeprecation = 3 < \func_num_args() && func_get_arg(3);
+        $hasRuntimeApi = class_exists(InstalledVersions::class);
+
+        if (!$hasRuntimeApi && !$skipDeprecation) {
+            trigger_deprecation('symfony/dependency-injection', '5.4', 'Calling "%s" when dependencies have been installed with Composer 1 is deprecated. Consider upgrading to Composer 2.', __METHOD__);
+        }
+
         if (!class_exists($class) && !interface_exists($class, false) && !trait_exists($class, false)) {
             return false;
         }
 
-        if (!class_exists(InstalledVersions::class) || !InstalledVersions::isInstalled($package) || InstalledVersions::isInstalled($package, false)) {
+        if (!$hasRuntimeApi || !InstalledVersions::isInstalled($package) || InstalledVersions::isInstalled($package, false)) {
             return true;
         }