bug symfony#29131 [Dotenv] dont use getenv() to read SYMFONY_DOTENV_VARS (nicolas-grekas)

This PR was merged into the 3.4 branch.

Discussion
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[Dotenv] dont use getenv() to read SYMFONY_DOTENV_VARS

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Since using it is not thread safe, let's not rely on it (already done in other places.)

Commits
-------

21a909a [Dotenv] dont use getenv() to read SYMFONY_DOTENV_VARS

Author: nicolas-grekas

src/Symfony/Component/Dotenv/Dotenv.php

@@ -66,8 +66,8 @@ public function load($path/*, ...$paths*/)
      */
     public function populate($values)
     {
-        $loadedVars = array_flip(explode(',', getenv('SYMFONY_DOTENV_VARS')));
-        unset($loadedVars['']);
+        $updateLoadedVars = false;
+        $loadedVars = array_flip(explode(',', isset($_SERVER['SYMFONY_DOTENV_VARS']) ? $_SERVER['SYMFONY_DOTENV_VARS'] : (isset($_ENV['SYMFONY_DOTENV_VARS']) ? $_ENV['SYMFONY_DOTENV_VARS'] : '')));
 
         foreach ($values as $name => $value) {
             $notHttpName = 0 !== strpos($name, 'HTTP_');
@@ -82,14 +82,15 @@ public function populate($values)
                 $_SERVER[$name] = $value;
             }
 
-            $loadedVars[$name] = true;
+            if (!isset($loadedVars[$name])) {
+                $loadedVars[$name] = $updateLoadedVars = true;
+            }
         }
 
-        if ($loadedVars) {
+        if ($updateLoadedVars) {
+            unset($loadedVars['']);
             $loadedVars = implode(',', array_keys($loadedVars));
-            putenv("SYMFONY_DOTENV_VARS=$loadedVars");
-            $_ENV['SYMFONY_DOTENV_VARS'] = $loadedVars;
-            $_SERVER['SYMFONY_DOTENV_VARS'] = $loadedVars;
+            putenv('SYMFONY_DOTENV_VARS='.$_ENV['SYMFONY_DOTENV_VARS'] = $_SERVER['SYMFONY_DOTENV_VARS'] = $loadedVars);
         }
     }
 

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

@@ -268,7 +268,7 @@ public function testMemorizingLoadedVarsNamesInSpecialVar()
 
     public function testOverridingEnvVarsWithNamesMemorizedInSpecialVar()
     {
-        putenv('SYMFONY_DOTENV_VARS=FOO,BAR,BAZ');
+        putenv('SYMFONY_DOTENV_VARS='.$_SERVER['SYMFONY_DOTENV_VARS'] = 'FOO,BAR,BAZ');
 
         putenv('FOO=foo');
         putenv('BAR=bar');