bug symfony#23878 [VarDumper] play nice with open_basedir when looking for composer.json (nicolas-grekas)

This PR was merged into the 3.3 branch.

Discussion
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[VarDumper] play nice with open_basedir when looking for composer.json

| Q             | A
| ------------- | ---
| Branch?       | 3.3
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#23661
| License       | MIT
| Doc PR        | -

ping @pounard, can you please confirm this fixes the issue you reported?

Commits
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1bea774 [VarDumper] play nice with open_basedir when looking for composer.json

Author: nicolas-grekas

src/Symfony/Component/VarDumper/Caster/LinkStub.php

@@ -89,7 +89,11 @@ private function getComposerRoot($file, &$inVendor)
         }
 
         $parent = $dir;
-        while (!file_exists($parent.'/composer.json')) {
+        while (!@file_exists($parent.'/composer.json')) {
+            if (!@file_exists($parent)) {
+                // open_basedir restriction in effect
+                break;
+            }
             if ($parent === dirname($parent)) {
                 return self::$composerRoots[$dir] = false;
             }