Nested Ternary

ID

php.nested_ternary

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Php

Tags

readability, simplification

Description

Reports a ternary conditional expression (cond ? a : b, or the short form a ?: b) that contains another ternary in its condition or in either of its branches. The maximum allowed nesting depth is configurable through the maxTernaryDepth property (default 1, meaning any ternary placed inside another is flagged).

Rationale

A single ternary is a compact, readable replacement for a small if/else. Once ternaries are stacked inside one another the expression becomes a puzzle: the reader has to track operator precedence and right-associativity to work out which branch belongs to which condition, and a misplaced parenthesis silently changes the result. The null-coalescing operator ?? is deliberately not treated as a ternary, so idiomatic fallback chains such as $a ?? $b ?? $default are left alone.

<?php
// FLAW — a ternary nested in the arm of another ternary
$label = $x > 0 ? ($x > 10 ? 'big' : 'small') : 'neg';

// OK — a single, flat ternary
$label = $x > 0 ? 'pos' : 'neg';

// OK — null-coalescing chain, not a ternary
$name = $first ?? $second ?? 'anonymous';

Remediation

Unfold the nested ternary into an if/elseif/else chain, or replace it with a match expression when each branch maps a value to a result. Both forms make every condition and its outcome explicit and remove the precedence guesswork.

References