rectorphp/rector · error · ShouldNotHappenException

"%s" is deprecated, as match(true) with nested conditions is

Error message

"%s" is deprecated, as match(true) with nested conditions is often less readable than the original ternary

What it means

NestedTernaryToMatchRector used to rewrite assignments containing nested ternaries into match (true) expressions. It is deprecated because match(true) with nested conditions is often LESS readable than the original ternary chain, especially for non-trivial conditions. refactor() now throws ShouldNotHappenException on every Assign node; the class was kept as a placeholder so deprecated registrations abort loudly.

Source

Thrown at rules/CodingStyle/Rector/Assign/NestedTernaryToMatchRector.php:56

        };
    }
}
CODE_SAMPLE
)]);
    }
    /**
     * @return array<class-string<Node>>
     */
    public function getNodeTypes(): array
    {
        return [Assign::class];
    }
    /**
     * @param Assign $node
     */
    public function refactor(Node $node): ?Assign
    {
        throw new ShouldNotHappenException(sprintf('"%s" is deprecated, as match(true) with nested conditions is often less readable than the original ternary', self::class));
    }
}

View on GitHub (pinned to 408fcb0ff1)

Solutions

Remove NestedTernaryToMatchRector::class from rector.php and imported sets, then re-run vendor/bin/rector dry-run
Convert genuinely hairy nested ternaries to match (true) manually, only where it improves clarity
Alternatively flatten deep ternaries into if/elseif or a lookup map, case by case
grep -r NestedTernaryToMatchRector across configs to eliminate every registration

Example fix

// before (rector.php)
->withRules([
    \Rector\CodingStyle\Rector\Assign\NestedTernaryToMatchRector::class,
]);
// code:
$level = $score > 90 ? 'high' : ($score > 50 ? 'mid' : 'low');

// after (rector.php)
// rule removed
// code rewritten by hand where it helps:
$level = match (true) {
    $score > 90 => 'high',
    $score > 50 => 'mid',
    default => 'low',
};

Defensive patterns

Strategy: validation

Validate before calling

$deprecated = ['NestedTernaryToMatchRector'];
foreach (glob(__DIR__ . '/rector*.php') as $config) {
    $src = file_get_contents($config);
    foreach ($deprecated as $rule) {
        if (str_contains($src, $rule)) {
            fwrite(STDERR, "Remove deprecated rule {$rule} from {$config}\n");
            exit(1);
        }
    }
}

Prevention

Convert nested ternaries to match (true) by hand, case by case
Delete rules from rector.php when the upstream version deprecates them
Avoid rules matching broad node types like Assign unless clearly valuable
Gate rector dry-run in CI so config rot is caught early

When it happens

Trigger: Registering rules/CodingStyle/Rector/Assign/NestedTernaryToMatchRector.php in config and running rector over any file with an assignment statement (the rule matches all Assign nodes, so effectively every file). The throw comes from rules/CodingStyle/Rector/Assign/NestedTernaryToMatchRector.php:56.

Common situations: A rector.php with a hand-tuned CodingStyle rule list, or an imported set package, still names NestedTernaryToMatchRector after upgrading Rector. Because Assign matches almost every PHP file, the exception surfaces on the first file processed and is frequently misread as a Rector internals bug.

Related errors

AI-assisted analysis of rectorphp/rector@408fcb0ff1 (2026-08-21). Data as JSON: /api/errors/67ae4d9e53891b76. Report an issue: GitHub.