bug #36993 [ErrorHandler] fix setting $trace to null in FatalError (n…

…icolas-grekas)

This PR was merged into the 4.4 branch.

Discussion
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[ErrorHandler] fix setting $trace to null in FatalError

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Spotted by @nikic in php/php-src#5620 (comment)

Commits
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aa50c92 [ErrorHandler] fix setting $trace to null in FatalError

src/Symfony/Component/ErrorHandler/Error/FatalError.php

@@ -72,9 +72,11 @@ public function __construct(string $message, int $code, array $error, int $trace
             'line' => $error['line'],
             'trace' => $trace,
         ] as $property => $value) {
-            $refl = new \ReflectionProperty(\Error::class, $property);
-            $refl->setAccessible(true);
-            $refl->setValue($this, $value);
+            if (null !== $value) {
+                $refl = new \ReflectionProperty(\Error::class, $property);
+                $refl->setAccessible(true);
+                $refl->setValue($this, $value);
+            }
         }
     }