bug #32943 [Dotenv] search variable values in ENV first then env file…

… (soufianZantar)

This PR was merged into the 3.4 branch.

Discussion
----------

[Dotenv] search variable values in ENV first then env file

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #32595
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

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understand your PR and can be used as a start for the documentation.

Additionally (see https://symfony.com/roadmap):
 - Bug fixes must be submitted against the lowest maintained branch where they apply
   (lowest branches are regularly merged to upper ones so they get the fixes too).
 - Features and deprecations must be submitted against branch 4.4.
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-->

I think we must searhing the value of variables in $_ENV before the .env file to fix this issues.
before this fix Parse method will return the value in .env file and not the value passed in this command `composer dump-env prod `.

**the issue:**

In my .env file, I have a variable TEST that depends on the APP_ENV variable like this:

```
# .env file

###> symfony/framework-bundle ###
APP_ENV=dev
APP_SECRET=2eb810c79fba0dd5c029a2fa53bfdb51
###< symfony/framework-bundle ###

TEST=foo_${APP_ENV}

```
I run composer dump-env dev command to generate my .env.locale.php, everything works fine, the value of my variable TEST is correct.

```
// .env.locale.php

return array (
  'APP_ENV' => 'dev',
  'TEST' => 'foo_dev',
  'APP_SECRET' => '2eb810c79fba0dd5c029a2fa53bfdb51',
);
```
Then I run the same command with prod environment (composer dump-env prod), the value of TEST is wrong (it is same as for dev)

```
// .env.locale.php

return array (
  'APP_ENV' => 'prod',
  'TEST' => 'foo_dev',
  'APP_SECRET' => '2eb810c79fba0dd5c029a2fa53bfdb51',
);
```

Commits
-------

3018041 [Dotenv] search variable values in ENV first then env file

src/Symfony/Component/Dotenv/Dotenv.php

@@ -183,6 +183,8 @@ private function lexValue()
             throw $this->createFormatException('Whitespace are not supported before the value');
         }
 
+        $loadedVars = array_flip(explode(',', isset($_SERVER['SYMFONY_DOTENV_VARS']) ? $_SERVER['SYMFONY_DOTENV_VARS'] : (isset($_ENV['SYMFONY_DOTENV_VARS']) ? $_ENV['SYMFONY_DOTENV_VARS'] : '')));
+        unset($loadedVars['']);
         $v = '';
 
         do {
@@ -224,8 +226,8 @@ private function lexValue()
                 ++$this->cursor;
                 $value = str_replace(['\\"', '\r', '\n'], ['"', "\r", "\n"], $value);
                 $resolvedValue = $value;
-                $resolvedValue = $this->resolveVariables($resolvedValue);
-                $resolvedValue = $this->resolveCommands($resolvedValue);
+                $resolvedValue = $this->resolveVariables($resolvedValue, $loadedVars);
+                $resolvedValue = $this->resolveCommands($resolvedValue, $loadedVars);
                 $resolvedValue = str_replace('\\\\', '\\', $resolvedValue);
                 $v .= $resolvedValue;
             } else {
@@ -247,8 +249,8 @@ private function lexValue()
                 }
                 $value = rtrim($value);
                 $resolvedValue = $value;
-                $resolvedValue = $this->resolveVariables($resolvedValue);
-                $resolvedValue = $this->resolveCommands($resolvedValue);
+                $resolvedValue = $this->resolveVariables($resolvedValue, $loadedVars);
+                $resolvedValue = $this->resolveCommands($resolvedValue, $loadedVars);
                 $resolvedValue = str_replace('\\\\', '\\', $resolvedValue);
 
                 if ($resolvedValue === $value && preg_match('/\s+/', $value)) {
@@ -301,7 +303,7 @@ private function skipEmptyLines()
         }
     }
 
-    private function resolveCommands($value)
+    private function resolveCommands($value, $loadedVars)
     {
         if (false === strpos($value, '$')) {
             return $value;
@@ -317,7 +319,7 @@ private function resolveCommands($value)
             )
         /x';
 
-        return preg_replace_callback($regex, function ($matches) {
+        return preg_replace_callback($regex, function ($matches) use ($loadedVars) {
             if ('\\' === $matches[1]) {
                 return substr($matches[0], 1);
             }
@@ -332,7 +334,15 @@ private function resolveCommands($value)
 
             $process = new Process('echo '.$matches[0]);
             $process->inheritEnvironmentVariables(true);
-            $process->setEnv($this->values);
+
+            $env = [];
+            foreach ($this->values as $name => $value) {
+                if (isset($loadedVars[$name]) || (!isset($_ENV[$name]) && !(isset($_SERVER[$name]) && 0 !== strpos($name, 'HTTP_')))) {
+                    $env[$name] = $value;
+                }
+            }
+            $process->setEnv($env);
+
             try {
                 $process->mustRun();
             } catch (ProcessException $e) {
@@ -343,7 +353,7 @@ private function resolveCommands($value)
         }, $value);
     }
 
-    private function resolveVariables($value)
+    private function resolveVariables($value, array $loadedVars)
     {
         if (false === strpos($value, '$')) {
             return $value;
@@ -359,7 +369,7 @@ private function resolveVariables($value)
             (?P<closing_brace>\})?             # optional closing brace
         /x';
 
-        $value = preg_replace_callback($regex, function ($matches) {
+        $value = preg_replace_callback($regex, function ($matches) use ($loadedVars) {
             // odd number of backslashes means the $ character is escaped
             if (1 === \strlen($matches['backslashes']) % 2) {
                 return substr($matches[0], 1);
@@ -375,14 +385,16 @@ private function resolveVariables($value)
             }
 
             $name = $matches['name'];
-            if (isset($this->values[$name])) {
+            if (isset($loadedVars[$name]) && isset($this->values[$name])) {
                 $value = $this->values[$name];
-            } elseif (isset($_SERVER[$name]) && 0 !== strpos($name, 'HTTP_')) {
-                $value = $_SERVER[$name];
             } elseif (isset($_ENV[$name])) {
                 $value = $_ENV[$name];
+            } elseif (isset($_SERVER[$name]) && 0 !== strpos($name, 'HTTP_')) {
+                $value = $_SERVER[$name];
+            } elseif (isset($this->values[$name])) {
+                $value = $this->values[$name];
             } else {
-                $value = (string) getenv($name);
+                $value = '';
             }
 
             if (!$matches['opening_brace'] && isset($matches['closing_brace'])) {

src/Symfony/Component/Dotenv/Tests/DotenvTest.php

@@ -63,6 +63,7 @@ public function testParse($data, $expected)
     public function getEnvData()
     {
         putenv('LOCAL=local');
+        $_ENV['LOCAL'] = 'local';
         $_ENV['REMOTE'] = 'remote';
 
         $tests = [
@@ -295,4 +296,20 @@ public function testOverridingEnvVarsWithNamesMemorizedInSpecialVar()
         $this->assertSame('baz1', getenv('BAZ'));
         $this->assertSame('/var/www', getenv('DOCUMENT_ROOT'));
     }
+
+    public function testGetVariablesValueFromEnvFirst()
+    {
+        $_ENV['APP_ENV'] = 'prod';
+        $dotenv = new Dotenv(true);
+
+        $test = "APP_ENV=dev\nTEST1=foo1_\${APP_ENV}";
+        $values = $dotenv->parse($test);
+        $this->assertSame('foo1_prod', $values['TEST1']);
+
+        if ('\\' !== \DIRECTORY_SEPARATOR) {
+            $test = "APP_ENV=dev\nTEST2=foo2_\$(php -r 'echo \$_SERVER[\"APP_ENV\"];')";
+            $values = $dotenv->parse($test);
+            $this->assertSame('foo2_prod', $values['TEST2']);
+        }
+    }
 }

src/Symfony/Component/Dotenv/composer.json

@@ -19,7 +19,7 @@
         "php": "^5.5.9|>=7.0.8"
     },
     "require-dev": {
-        "symfony/process": "~3.2|~4.0"
+        "symfony/process": "^3.4.2|^4.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Dotenv\\": "" },