Support both composer 2.2 and 2.3+ on PHP 7.4

src/HordeInstaller.php

@@ -25,7 +25,15 @@ class HordeInstaller extends LibraryInstaller
     public function reconfigure(): void
     {
         $mode = \strncasecmp(\PHP_OS, 'WIN', 3) === 0 ? 'copy' : 'symlink';
-        $flow = HordeReconfigureFlow::fromComposer($this->composer, new ComposerIoAdapter($this->io));
+        // This is needed to support PHP 7.4 (no union types) for both Composer 2.2 / 2.3
+        // Cannot use instanceof here as the class will not exist in 2.2.
+        if (get_class($this->composer) === 'Composer\PartialComposer') {
+            $flow = HordeReconfigureFlow::fromPartialComposer($this->composer, new ComposerIoAdapter($this->io));
+        } else {
+            // @phpstan-ignore-next-line
+            $flow = HordeReconfigureFlow::fromComposer($this->composer, new ComposerIoAdapter($this->io));
+        }
+
         $flow->run();
     }
 

src/HordeReconfigureCommand.php

@@ -36,7 +36,13 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         if (!$composer) {
             die('Error: Command was run without a relation to composer itself');
         }
-        $flow = HordeReconfigureFlow::fromComposer($composer, new SymphonyOutputAdapter($output));
+        // This is needed to support PHP 7.4 (no union types) for both Composer 2.2 / 2.3
+        // Cannot use instanceof here as the class will not exist in 2.2.
+        if (get_class($composer) === 'Composer\PartialComposer') {
+            $flow = HordeReconfigureFlow::fromPartialComposer($composer, new SymphonyOutputAdapter($output));
+        } else {
+            $flow = HordeReconfigureFlow::fromComposer($composer, new SymphonyOutputAdapter($output));
+        }
         return $flow->run();
     }
 }

src/HordeReconfigureFlow.php

@@ -11,6 +11,7 @@
 
 use Composer\InstalledVersions;
 use Composer\PartialComposer;
+use Composer\Composer;
 use Composer\Util\Filesystem;
 use Composer\Factory as ComposerFactory;
 use Horde\Composer\IOAdapter\FlowIoInterface;
@@ -35,7 +36,35 @@ public function __construct(DirectoryTree $tree, FlowIoInterface $io, string $mo
         $this->tree = $tree;
     }
 
-    public static function fromComposer(PartialComposer $composer, ?FlowIoInterface $output = null): self
+    /**
+     * Named Constructor.
+     *
+     * @param Composer $composer
+     * @param FlowIoInterface|null $output
+     * @return self
+     */
+    public static function fromComposer(Composer $composer, ?FlowIoInterface $output = null): self
+    {
+        return self::fromAnyComposer($composer, $output);
+    }
+
+    public static function fromPartialComposer(PartialComposer $composer, ?FlowIoInterface $output = null): self
+    {
+        return self::fromAnyComposer($composer, $output);
+    }
+
+    /**
+     * Actual implementation of fromComposer / fromPartialComposer named constructors
+     *
+     * Composer may provide a PartialCompoer or a Composer object.
+     * Use fromComposer and fromPartialComposer frontends
+     *
+     * @param Composer|PartialComposer $composer  A (partial) composer instance
+     * @param FlowIoInterface|null $output An IO interface
+     *
+     * @TODO Refactor this once we require PHP 8.0 or higher
+     */
+    private static function fromAnyComposer($composer, ?FlowIoInterface $output = null): self
     {
         $mode = \strncasecmp(\PHP_OS, 'WIN', 3) === 0 ? 'copy' : 'symlink';
         $tree = DirectoryTree::fromComposerJsonPath(ComposerFactory::getComposerFile());