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copied!<p>Someone will correct me if I am wrong, but PHP is actually detecting recursion at the right moment. Your assignation simply creates the additional cycle. The example should be:</p> <pre><code>$arr = array(); $arr = array(&$arr); </code></pre> <p>Which will result in</p> <pre><code>array(1) { [0]=> &array(1) { [0]=> *RECURSION* } } </code></pre> <p>As expected.</p> <hr> <p>Well, I got a bit curious myself how to detect recursion and I started to Google. I found this article <a href="http://noteslog.com/post/detecting-recursive-dependencies-in-php-composite-values/" rel="nofollow">http://noteslog.com/post/detecting-recursive-dependencies-in-php-composite-values/</a> and this solution:</p> <pre><code>function hasRecursiveDependency($value) { //if PHP detects recursion in a $value, then a printed $value //will contain at least one match for the pattern /\*RECURSION\*/ $printed = print_r($value, true); $recursionMetaUser = preg_match_all('@\*RECURSION\*@', $printed, $matches); if ($recursionMetaUser == 0) { return false; } //if PHP detects recursion in a $value, then a serialized $value //will contain matches for the pattern /\*RECURSION\*/ never because //of metadata of the serialized $value, but only because of user data $serialized = serialize($value); $recursionUser = preg_match_all('@\*RECURSION\*@', $serialized, $matches); //all the matches that are user data instead of metadata of the //printed $value must be ignored $result = $recursionMetaUser > $recursionUser; return $result; } </code></pre>

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