[DependencyInjection] Fix loading all env vars from secrets when only a subset is needed

Author: nicolas-grekas

EnvVarLoaderInterface.php

@@ -19,7 +19,7 @@
 interface EnvVarLoaderInterface
 {
     /**
-     * @return string[] Key/value pairs that can be accessed using the regular "%env()%" syntax
+     * @return array<string|\Stringable> Key/value pairs that can be accessed using the regular "%env()%" syntax
      */
     public function loadEnvVars(): array;
 }

EnvVarProcessor.php

@@ -164,10 +164,16 @@ public function getEnv(string $prefix, string $name, \Closure $getEnv): mixed
         if (false !== $i || 'string' !== $prefix) {
             $env = $getEnv($name);
         } elseif ('' === ($env = $_ENV[$name] ?? (str_starts_with($name, 'HTTP_') ? null : ($_SERVER[$name] ?? null)))
-            || (false !== $env && false === ($env = $env ?? getenv($name) ?? false)) // null is a possible value because of thread safety issues
+            || (false !== $env && false === $env ??= getenv($name) ?? false) // null is a possible value because of thread safety issues
         ) {
-            foreach ($this->loadedVars as $vars) {
-                if (false !== ($env = ($vars[$name] ?? $env)) && '' !== $env) {
+            foreach ($this->loadedVars as $i => $vars) {
+                if (false === $env = $vars[$name] ?? $env) {
+                    continue;
+                }
+                if ($env instanceof \Stringable) {
+                    $this->loadedVars[$i][$name] = $env = (string) $env;
+                }
+                if ('' !== ($env ?? '')) {
                     break;
                 }
             }
@@ -185,7 +191,13 @@ public function getEnv(string $prefix, string $name, \Closure $getEnv): mixed
                             continue;
                         }
                         $this->loadedVars[] = $vars = $loader->loadEnvVars();
-                        if (false !== ($env = ($vars[$name] ?? $env)) && '' !== $env) {
+                        if (false === $env = $vars[$name] ?? $env) {
+                            continue;
+                        }
+                        if ($env instanceof \Stringable) {
+                            $this->loadedVars[array_key_last($this->loadedVars)][$name] = $env = (string) $env;
+                        }
+                        if ('' !== ($env ?? '')) {
                             $ended = false;
                             break;
                         }

Tests/EnvVarProcessorTest.php

@@ -808,6 +808,12 @@ public function loadEnvVars(): array
                     return [
                         'FOO_ENV_LOADER' => '123',
                         'BAZ_ENV_LOADER' => '',
+                        'LAZY_ENV_LOADER' => new class() {
+                            public function __toString()
+                            {
+                                return '';
+                            }
+                        },
                     ];
                 }
             };
@@ -819,6 +825,12 @@ public function loadEnvVars(): array
                         'FOO_ENV_LOADER' => '234',
                         'BAR_ENV_LOADER' => '456',
                         'BAZ_ENV_LOADER' => '567',
+                        'LAZY_ENV_LOADER' => new class() {
+                            public function __toString()
+                            {
+                                return '678';
+                            }
+                        },
                     ];
                 }
             };
@@ -841,6 +853,9 @@ public function loadEnvVars(): array
         $result = $processor->getEnv('string', 'FOO_ENV_LOADER', function () {});
         $this->assertSame('123', $result); // check twice
 
+        $result = $processor->getEnv('string', 'LAZY_ENV_LOADER', function () {});
+        $this->assertSame('678', $result);
+
         unset($_ENV['BAZ_ENV_LOADER']);
         unset($_ENV['BUZ_ENV_LOADER']);
     }