phanalist

E0051: Count of a Non-Countable Value

In plain English: count() works on arrays and on objects that implement Countable. Passing a string, number, boolean, or null is an error in PHP 8.

Why it matters: The code throws a TypeError instead of returning a length, so the request or job can fail at runtime.

Bad

count('hello'); // TypeError
sizeof(42);     // TypeError
count(null);    // TypeError

Good

count($items);      // $items is an array
sizeof($collection); // $collection implements Countable
strlen($text);      // use strlen() for strings

What the rule checks

• count() or sizeof() with a string literal
• count() or sizeof() with an integer or float literal
• count() or sizeof() with a boolean or null literal

When it does not report

• The argument is a literal array.
• The argument is a variable or expression whose type is unknown.
• The argument is a constant, class constant, or function result.
• The value comes from a class that implements Countable.

How to fix

• Use strlen() for strings.
• Remove count() when the value is a scalar.
• Check the type first if the value can be different types.
• Use an array or a Countable object when you need a count.

Configuration

E0051 has no configuration options and is enabled by default.

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