Make environment loading compatible with Plesk

app.php

@@ -8,8 +8,12 @@ declare(strict_types=1);
  * env_vars.php file is loaded when present so existing installations keep
  * working during migration.
  */
+$appFileEnvironment = [];
+
 function app_load_env_file(string $filename): void
 {
+    global $appFileEnvironment;
+
     if (!is_file($filename)) {
         return;
     }
@@ -57,8 +61,9 @@ function app_load_env_file(string $filename): void
             continue;
         }
 
-        // Real process variables and legacy configuration always take precedence.
-        if (getenv($name) !== false) {
+        // Non-empty process variables and legacy configuration take precedence.
+        $processValue = getenv($name);
+        if ($processValue !== false && trim((string)$processValue) !== '') {
             continue;
         }
 
@@ -78,7 +83,7 @@ function app_load_env_file(string $filename): void
             continue;
         }
 
-        putenv($name . '=' . $value);
+        $appFileEnvironment[$name] = $value;
         $_ENV[$name] = $value;
     }
 }
@@ -92,8 +97,18 @@ app_load_env_file(dirname(__DIR__) . DIRECTORY_SEPARATOR . '.env');
 
 function app_env(string $name, string $default = ''): string
 {
+    global $appFileEnvironment;
+
     $value = getenv($name);
-    return $value === false ? $default : trim((string)$value);
+    if ($value !== false && trim((string)$value) !== '') {
+        return trim((string)$value);
+    }
+
+    if (array_key_exists($name, $appFileEnvironment)) {
+        return trim((string)$appFileEnvironment[$name]);
+    }
+
+    return $default;
 }
 
 function app_env_int(string $name, int $default, int $min, int $max): int