From 3a604ac39243990983554fa397c4a58e300c7e91 Mon Sep 17 00:00:00 2001
From: Beno!t POLASZEK <bpolaszek@gmail.com>
Date: Tue, 8 Jan 2019 11:24:53 +0100
Subject: [PATCH] Nullable environment variable processor

---
 .../DependencyInjection/CHANGELOG.md          |  1 +
 .../DependencyInjection/EnvVarProcessor.php   |  5 ++++
 .../RegisterEnvVarProcessorsPassTest.php      |  1 +
 .../Tests/EnvVarProcessorTest.php             | 25 +++++++++++++++++++
 4 files changed, 32 insertions(+)

diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
index 7afa4a21b89a0..c3f17d360c8c6 100644
--- a/src/Symfony/Component/DependencyInjection/CHANGELOG.md
+++ b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -6,6 +6,7 @@ CHANGELOG
 
  * added `%env(trim:...)%` processor to trim a string value
  * added `%env(default:...)%` processor to fallback to a default value
+ * added `%env(nullable:...)%` processor to allow empty variables to be processed as null values
 
 4.2.0
 -----
diff --git a/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php b/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php
index 1b71924d8a719..da4e2d9f7ac62 100644
--- a/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php
+++ b/src/Symfony/Component/DependencyInjection/EnvVarProcessor.php
@@ -41,6 +41,7 @@ public static function getProvidedTypes()
             'int' => 'int',
             'json' => 'array',
             'key' => 'bool|int|float|string|array',
+            'nullable' => 'bool|int|float|string|array',
             'resolve' => 'string',
             'default' => 'bool|int|float|string|array',
             'string' => 'string',
@@ -195,6 +196,10 @@ public function getEnv($prefix, $name, \Closure $getEnv)
             return str_getcsv($env);
         }
 
+        if ('nullable' === $prefix) {
+            return '' === $env ? null : $env;
+        }
+
         if ('trim' === $prefix) {
             return trim($env);
         }
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/RegisterEnvVarProcessorsPassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/RegisterEnvVarProcessorsPassTest.php
index f376165dfc0a1..7d73f6cfb37e9 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/RegisterEnvVarProcessorsPassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/RegisterEnvVarProcessorsPassTest.php
@@ -39,6 +39,7 @@ public function testSimpleProcessor()
             'int' => ['int'],
             'json' => ['array'],
             'key' => ['bool', 'int', 'float', 'string', 'array'],
+            'nullable' => ['bool', 'int', 'float', 'string', 'array'],
             'resolve' => ['string'],
             'default' => ['bool', 'int', 'float', 'string', 'array'],
             'string' => ['string'],
diff --git a/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php b/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php
index 0ae6f4b0ef2e7..31614ce7d064f 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/EnvVarProcessorTest.php
@@ -433,4 +433,29 @@ public function testGetEnvKeyChained()
             ];
         }));
     }
+
+    /**
+     * @dataProvider validNullables
+     */
+    public function testGetEnvNullable($value, $processed)
+    {
+        $processor = new EnvVarProcessor(new Container());
+        $result = $processor->getEnv('nullable', 'foo', function ($name) use ($value) {
+            $this->assertSame('foo', $name);
+
+            return $value;
+        });
+        $this->assertSame($processed, $result);
+    }
+
+    public function validNullables()
+    {
+        return [
+            ['hello', 'hello'],
+            ['', null],
+            ['null', 'null'],
+            ['Null', 'Null'],
+            ['NULL', 'NULL'],
+         ];
+    }
 }