fix: Revert incorrect requirement bump (#183)

I intended to bump the minimum required Composer version in #177,
unfortunately I missed to adjust the actual constraint `composer-plugin-api`
there, resulting in issues to users.

This PR restores support for older Composer versions.

Closes #182.

Author: theofidry

.github/workflows/tests.yaml

@@ -30,7 +30,7 @@ jobs:
                 dependency-versions: [ "highest" ]
                 include:
                     - php: "7.2"
-                      tools: "composer:v2.6"
+                      tools: "composer:v2.2"
                       dependency-versions: "lowest"
 
         steps:

composer.json

@@ -17,7 +17,7 @@
     },
     "require-dev": {
         "ext-json": "*",
-        "composer/composer": "^2.6",
+        "composer/composer": "^2.2.26",
         "phpstan/extension-installer": "^1.1",
         "phpstan/phpstan": "^1.8 || ^2.0",
         "phpstan/phpstan-phpunit": "^1.1 || ^2.0",

src/Command/BinCommand.php

@@ -26,6 +26,7 @@
 use function file_put_contents;
 use function getcwd;
 use function glob;
+use function method_exists;
 use function min;
 use function mkdir;
 use function putenv;
@@ -96,7 +97,11 @@ public function isProxyCommand(): bool
 
     public function execute(InputInterface $input, OutputInterface $output): int
     {
-        $composer = $this->requireComposer();
+        // Switch to requireComposer() once Composer 2.3 is set as the minimum
+        // @phpstan-ignore function.alreadyNarrowedType
+        $composer = method_exists($this, 'requireComposer')
+            ? $this->requireComposer()
+            : $this->getComposer();
 
         $config = Config::fromComposer($composer);
         $currentWorkingDir = getcwd();

tests/Fixtures/MyTestCommand.php

@@ -12,6 +12,8 @@
 use Composer\Factory;
 use Composer\IO\NullIO;
 
+use function method_exists;
+
 class MyTestCommand extends BaseCommand
 {
     /**
@@ -39,7 +41,11 @@ public function __construct()
 
     public function execute(InputInterface $input, OutputInterface $output): int
     {
-        $this->composer = $this->tryComposer();
+        // Switch to tryComposer() once Composer 2.3 is set as the minimum
+        // @phpstan-ignore function.alreadyNarrowedType
+        $this->composer = method_exists($this, 'tryComposer')
+            ? $this->tryComposer()
+            : $this->getComposer(false);
 
         $factory = Factory::create(new NullIO());
         $config = $factory->getConfig();