bug symfony#29171 [Dotenv] load .env.dist when it exists and .env is not found (nicolas-grekas)

This PR was merged into the 4.2-dev branch.

Discussion
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[Dotenv] load .env.dist when it exists and .env is not found

| Q             | A
| ------------- | ---
| Branch?       | 4.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#29170
| License       | MIT
| Doc PR        | -

As illustrated in symfony#29170, it can be useful to opt out from the `.env` convention and fall back to defining env vars in `.env.dist` instead. This PR allows that by loading `.env.dist` when it exists and `.env` is not found.

Needs symfony/flex#434 to work seamlessly when using Flex.

Commits
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841185b [Dotenv] load .env.dist when it exists and .env is not found

Author: nicolas-grekas

src/Symfony/Component/Dotenv/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * added `Dotenv::overload()` and `$overrideExistingVars` as optional parameter of `Dotenv::populate()`
+ * added `Dotenv::loadEnv()` to load a .env file and its corresponding .env.local, .env.$env and .env.$env.local files if they exist
 
 3.3.0
 -----

src/Symfony/Component/Dotenv/Dotenv.php

@@ -55,6 +55,7 @@ public function load(string $path, string ...$extraPaths): void
      * Loads a .env file and the corresponding .env.local, .env.$env and .env.$env.local files if they exist.
      *
      * .env.local is always ignored in test env because tests should produce the same results for everyone.
+     * .env.dist is loaded when it exists and .env is not found.
      *
      * @param string $path       A file to load
      * @param string $varName    The name of the env vars that defines the app env
@@ -66,7 +67,11 @@ public function load(string $path, string ...$extraPaths): void
      */
     public function loadEnv(string $path, string $varName = 'APP_ENV', string $defaultEnv = 'dev', array $testEnvs = array('test')): void
     {
-        $this->load($path);
+        if (file_exists($path) || !file_exists($p = "$path.dist")) {
+            $this->load($path);
+        } else {
+            $this->load($p);
+        }
 
         if (null === $env = $_SERVER[$varName] ?? $_ENV[$varName] ?? null) {
             $this->populate(array($varName => $env = $defaultEnv));

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

@@ -231,11 +231,18 @@ public function testLoadEnv()
         (new DotEnv())->loadEnv($path, 'TEST_APP_ENV');
         $this->assertSame('devlocalBAR', getenv('FOO'));
 
+        // .env.dist
+
+        unlink($path);
+        file_put_contents("$path.dist", 'BAR=distBAR');
+        (new DotEnv())->loadEnv($path, 'TEST_APP_ENV');
+        $this->assertSame('distBAR', getenv('BAR'));
+
         putenv('FOO');
         putenv('BAR');
-        unlink($path);
-        unlink("$path.dev");
+        unlink("$path.dist");
         unlink("$path.local");
+        unlink("$path.dev");
         unlink("$path.dev.local");
         rmdir($tmpdir);
     }