CodeIgniter Documentation Example Code Error | Explained and Fixed

The slash may be unnecessary, but the example is not in fact erroneous - multiple slashes should be and are in fact automatically reduced to a single one by PHP.

php > mkdir(__DIR__.DIRECTORY_SEPARATOR.'foo');
php > touch(__DIR__.DIRECTORY_SEPARATOR.'foo'.DIRECTORY_SEPARATOR.'bar');
php > var_dump(file_exists(__DIR__.DIRECTORY_SEPARATOR.'/////////////foo//////////////////////////////bar'));
bool(true)

So while I don't mind adjusting the docs, I'm more interested in the specifics of your environment, so we'd know why this is happening.

Can't believe that you're actually right. Now I'm trouble replicating the issue.. dam.