symfony · nicolas-grekas · Jan 20, 2020 · Jan 15, 2020
diff --git a/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php b/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php
@@ -30,8 +30,7 @@ class EnvVarProcessor implements EnvVarProcessorInterface
    public function __construct(ContainerInterface $container, \Traversable $loaders = null)
    {
        $this->container = $container;
-        $this->loaders = new \IteratorIterator($loaders ?? new \ArrayIterator());
-        $this->loaders = $this->loaders->getInnerIterator();
+        $this->loaders = $loaders ?? new \ArrayIterator();
    }

    /**
@@ -141,20 +140,32 @@ public function getEnv($prefix, $name, \Closure $getEnv)
                }
            }

-            $loaders = $this->loaders;
-            $this->loaders = new \ArrayIterator();
-
-            try {
-                while ((false === $env || null === $env) && $loaders->valid()) {
-                    $loader = $loaders->current();
-                    $loaders->next();
-                    $this->loadedVars[] = $vars = $loader->loadEnvVars();
-                    $env = $vars[$name] ?? false;
+            if (false === $env || null === $env) {
+                $loaders = $this->loaders;
+                $this->loaders = new \ArrayIterator();
+
+                try {
+                    $i = 0;
+                    $ended = true;
+                    $count = $loaders instanceof \Countable ? $loaders->count() : 0;
+                    foreach ($loaders as $loader) {
+                        if (\count($this->loadedVars) > $i++) {
+                            continue;
+                        }
+                        $this->loadedVars[] = $vars = $loader->loadEnvVars();
+                        if (false !== $env = $vars[$name] ?? false) {
+                            $ended = false;
+                            break;
+                        }
+                    }
+                    if ($ended || $count === $i) {
+                        $loaders = $this->loaders;
+                    }
+                } catch (ParameterCircularReferenceException $e) {
+                    // skip loaders that need an env var that is not defined
+                } finally {
+                    $this->loaders = $loaders;
                }
-            } catch (ParameterCircularReferenceException $e) {
-                // skip loaders that need an env var that is not defined
-            } finally {
-                $this->loaders = $loaders;
            }

            if (false === $env || null === $env) {

diff --git a/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php b/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php
@@ -3,10 +3,12 @@
 namespace Symfony\Component\DependencyInjection\Tests;

 use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
 use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\EnvVarLoaderInterface;
 use Symfony\Component\DependencyInjection\EnvVarProcessor;
+use Symfony\Component\DependencyInjection\Exception\ParameterCircularReferenceException;

 class EnvVarProcessorTest extends TestCase
 {
@@ -553,4 +555,44 @@ public function loadEnvVars(): array
        $result = $processor->getEnv('string', 'FOO_ENV_LOADER', function () {});
        $this->assertSame('123', $result); // check twice
    }
+
+    public function testCircularEnvLoader()
+    {
+        $container = new ContainerBuilder();
+        $container->setParameter('env(FOO_CONTAINER)', 'foo');
+        $container->compile();
+
+        $index = 0;
+        $loaders = function () use (&$index) {
+            if (0 === $index++) {
+                throw new ParameterCircularReferenceException(['FOO_CONTAINER']);
+            }
+
+            yield new class() implements EnvVarLoaderInterface {
+                public function loadEnvVars(): array
+                {
+                    return [
+                        'FOO_ENV_LOADER' => '123',
+                    ];
+                }
+            };
+        };
+
+        $processor = new EnvVarProcessor($container, new RewindableGenerator($loaders, 1));
+
+        $result = $processor->getEnv('string', 'FOO_CONTAINER', function () {});
+        $this->assertSame('foo', $result);
+
+        $result = $processor->getEnv('string', 'FOO_ENV_LOADER', function () {});
+        $this->assertSame('123', $result);
+
+        $result = $processor->getEnv('default', ':BAR_CONTAINER', function ($name) use ($processor) {
+            $this->assertSame('BAR_CONTAINER', $name);
+
+            return $processor->getEnv('string', $name, function () {});
+        });
+        $this->assertNull($result);
+
+        $this->assertSame(2, $index);
+    }
 }