Which is better in PHP: suppress warnings with '@' or run extra checks with isset()?

Question

For example, if I implement some simple object caching, which method is faster?

1. return isset($cache[$cls]) ? $cache[$cls] : $cache[$cls] = new $cls;

2. return @$cache[$cls] ?: $cache[$cls] = new $cls;

I read somewhere @ takes significant time to execute (and I wonder why), especially when warnings/notices are actually being issued and suppressed. isset() on the other hand means an extra hash lookup. So which is better and why?

I do want to keep E_NOTICE on globally, both on dev and production servers.

Answer 1

I wouldn't worry about which method is FASTER. That is a micro-optimization. I would worry more about which is more readable code and better coding practice.

I would certainly prefer your first option over the second, as your intent is much clearer. Also, best to keep away edge condition problems by always explicitly testing variables to make sure you are getting what you are expecting to get. For example, what if the class stored in $cache[$cls] is not of type $cls?

Personally, if I typically would not expect the index on $cache to be unset, then I would also put error handling in there rather than using ternary operations. If I could reasonably expect that that index would be unset on a regular basis, then I would make class $cls behave as a singleton and have your code be something like

return $cls::get_instance();