From 8026609dc906d1313f0e943896142555ddac3568 Mon Sep 17 00:00:00 2001
From: Christian Flothmann <christian.flothmann@sensiolabs.de>
Date: Sat, 23 Nov 2019 15:53:46 +0100
Subject: [PATCH] don't fail when referenced env var does not exist

---
 src/Symfony/Component/Dotenv/Dotenv.php           | 2 +-
 src/Symfony/Component/Dotenv/Tests/DotenvTest.php | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/Dotenv/Dotenv.php b/src/Symfony/Component/Dotenv/Dotenv.php
index de40ade592d2e..81bb08810eaac 100644
--- a/src/Symfony/Component/Dotenv/Dotenv.php
+++ b/src/Symfony/Component/Dotenv/Dotenv.php
@@ -466,7 +466,7 @@ private function resolveVariables(string $value, array $loadedVars): string
                 $value = '';
             }
 
-            if ('' === $value && isset($matches['default_value'])) {
+            if ('' === $value && isset($matches['default_value']) && '' !== $matches['default_value']) {
                 $unsupportedChars = strpbrk($matches['default_value'], '\'"{$');
                 if (false !== $unsupportedChars) {
                     throw $this->createFormatException(sprintf('Unsupported character "%s" found in the default value of variable "$%s".', $unsupportedChars[0], $name));
diff --git a/src/Symfony/Component/Dotenv/Tests/DotenvTest.php b/src/Symfony/Component/Dotenv/Tests/DotenvTest.php
index 3f232698aebf7..d4c7c53dcd2ba 100644
--- a/src/Symfony/Component/Dotenv/Tests/DotenvTest.php
+++ b/src/Symfony/Component/Dotenv/Tests/DotenvTest.php
@@ -172,6 +172,7 @@ public function getEnvData()
             ["FOO=BAR\nBAR=\${NOTDEFINED:=TEST}", ['FOO' => 'BAR', 'NOTDEFINED' => 'TEST', 'BAR' => 'TEST']],
             ["FOO=\nBAR=\${FOO:=TEST}", ['FOO' => 'TEST', 'BAR' => 'TEST']],
             ["FOO=\nBAR=\$FOO:=TEST}", ['FOO' => 'TEST', 'BAR' => 'TEST}']],
+            ["FOO=foo\nFOOBAR=\${FOO}\${BAR}", ['FOO' => 'foo', 'FOOBAR' => 'foo']],
         ];
 
         if ('\\' !== \DIRECTORY_SEPARATOR) {