Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php | ||
| 11 | * Filters $value to an integer strictly. | ||
| 12 | * | ||
| 13 | * $value must be an int or contain all digits, optionally prepended by a '+' or '-' and optionally surrounded by | ||
| 14 | * whitespace to pass the filter. | ||
| 15 | * | ||
| 16 | * The return value is the int, as expected by the \TraderInteractive\Filterer class. | ||
| 17 | * | ||
| 18 | * @param string|int $value the value to make an integer | ||
| 19 | * @param bool $allowNull Set to true if NULL values are allowed. The filtered result of a NULL value is NULL | ||
| 20 | * @param int $minValue The minimum acceptable value | ||
| 21 | * @param int $maxValue The maximum acceptable value | ||
| 22 | * | ||
| 23 | * @return int|null The filtered value | ||
| 24 | * | ||
| 25 | * @throws \InvalidArgumentException if $allowNull is not a boolean | ||
| 26 | * @throws \InvalidArgumentException if $minValue is not null and not an int | ||
| 27 | * @throws \InvalidArgumentException if $maxValue is not an int | ||
| 28 | * @throws Exception if $value string length is zero | ||
| 29 | * @throws Exception if $value does not contain all digits, optionally prepended by a '+' or '-' and optionally | ||
| 30 | * surrounded by whitespace | ||
| 31 | * @throws Exception if $value was greater than a max int of PHP_INT_MAX | ||
| 32 | * @throws Exception if $value was less than a min int of ~PHP_INT_MAX | ||
| 33 | * @throws Exception if $value is not a string | ||
| 34 | * @throws Exception if $value is less than $minValue | ||
| 35 | * @throws Exception if $value is greater than $maxValue | ||
| 36 | */ | ||
| 37 | public static function filter($value, bool $allowNull = false, int $minValue = null, int $maxValue = PHP_INT_MAX) | ||
| 93 | } | ||
| 94 | 
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVarassignment in line 1 and the$higherassignment in line 2 are dead. The first because$myVaris never used and the second because$higheris always overwritten for every possible time line.