Psalm Error Example

error.php

<?php

// This version replaces the redundant code with a recursive call, but emits these errors:
//
// ERROR: InvalidReturnType - src/Filter/FilterTransformer.php:111:16 - The declared return type 'Kiosk\Filter\PriceRange|array<array-key, Kiosk\Filter\PriceRange|float>|float' for Kiosk\Filter\FilterTransformer::getPrice is incorrect, got 'Kiosk\Filter\PriceRange|array<int|string(max)|string(min), Kiosk\Filter\PriceRange|array<array-key, Kiosk\Filter\PriceRange|float>|float>|float' (see https://psalm.dev/011)
//     * @return float|float[]|PriceRange|PriceRange[]
//
// ERROR: InvalidReturnStatement - src/Filter/FilterTransformer.php:130:16 - The inferred type 'array<int|string(max)|string(min), Kiosk\Filter\PriceRange|array<array-key, Kiosk\Filter\PriceRange|float>|float>' does not match the declared return type 'Kiosk\Filter\PriceRange|array<array-key, Kiosk\Filter\PriceRange|float>|float' for Kiosk\Filter\FilterTransformer::getPrice (see https://psalm.dev/128)
//         return array_map(
//             [$this, 'getPrice'],
//             $price
//         );

/**
 * @param string|float|array{min?: float|string, max?:float|string}|list<array{min?: float|string, max?:float|string}> $price
 * @return float|float[]|PriceRange|PriceRange[]
 */
private function getPrice($price)
{
    if (is_string($price) || is_float($price)) {
        return (float) $price;
    }

    if (isset($price['min']) || isset($price['max'])) {
        $range = new PriceRange;
        if (isset($price['min'])) {
            $range->setMin((float) $price['min']);
        }
        if (isset($price['max'])) {
            $range->setMax((float) $price['max']);
        }
        return $range;
    }

    return array_map(
        [$this, 'getPrice'],
        $price
    );
}

no-error.php

<?php

// This version produces no errors, but has repeated code in the array_map() call.

/**
 * @param string|float|array{min?: float|string, max?:float|string}|list<array{min?: float|string, max?:float|string}> $price
 * @return float|float[]|PriceRange|PriceRange[]
 */
private function getPrice($price)
{
    if (is_string($price) || is_float($price)) {
        return (float) $price;
    }

    if (isset($price['min']) || isset($price['max'])) {
        $range = new PriceRange;
        if (isset($price['min'])) {
            $range->setMin((float) $price['min']);
        }
        if (isset($price['max'])) {
            $range->setMax((float) $price['max']);
        }
        return $range;
    }

    return array_map(
        /**
         * @param string|float|array{min?: float|string, max?:float|string} $price
         * @return float|PriceRange
         */
        function ($price) {
            if (is_string($price) || is_float($price)) {
                return (float) $price;
            }

            $range = new PriceRange;
            if (isset($price['min'])) {
                $range->setMin((float) $price['min']);
            }
            if (isset($price['max'])) {
                $range->setMax((float) $price['max']);
            }
            return $range;
        },
        $price
    );
}