phanalist

E0050: Position Check Used as Boolean

In plain English: strpos() returns 0 when the match is at the very start of the string. PHP treats 0 as false, so if (strpos(...)) treats a match at position zero as “not found.”

Why it matters: A valid match can silently take the “not found” branch.

Bad

if (strpos($path, '/')) {
    // A leading slash is at position 0, so this branch is skipped.
}

Good

if (strpos($path, '/') !== false) {
    // Found, including a match at position 0.
}

if (str_starts_with($path, '/')) {
    // Clearer when you only care about the prefix.
}

What the rule checks

• if, elseif, while, do/while, and for conditions
• Negated checks such as !strpos($haystack, $needle)
• Checks combined with &&, ||, and, or, or xor
• Checks used as a ternary condition

A comparison makes the false result explicit. !== false, === 0, and >= 0 are accepted.

When it does not report

• The result is compared with false, 0, or another value.
• The position is stored in a variable and tested later.
• The call is behind a dynamic function name or an unresolved namespace.
• The call is inside a closure or arrow function body.

How to fix

• Use !== false when you only need “found or not found.”
• Use === 0 when you specifically mean “starts at position 0.”
• Prefer str_contains() or str_starts_with() on PHP 8+.

Configuration

E0050 has no configuration options and is enabled by default.

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