Generic Array Of Primitives
ID |
kotlin.generic_array_primitives |
Severity |
low |
Remediation Complexity |
medium |
Remediation Risk |
low |
Remediation Effort |
medium |
Resource |
Code Smell |
Language |
Kotlin |
Tags |
best-practice, performance |
Description
Reports type references of the form Array<Int>, Array<Long>, and similar where
the element type is a Kotlin primitive. Kotlin provides specialized array types
(IntArray, LongArray, etc.) that store values without boxing.
Rationale
Array<Int> is backed by Integer[] on the JVM — each element is a boxed Integer
object. IntArray is backed by int[] — primitive, unboxed, much smaller in memory,
and faster to access. The generic form should only be used when the nullability of
individual elements is required (Array<Int?>) or when the code must interoperate
with a generic algorithm that cannot accept IntArray.
// Bad
val ids: Array<Int> = arrayOf(1, 2, 3)
fun sum(values: Array<Long>): Long = values.sum()
// Good
val ids: IntArray = intArrayOf(1, 2, 3)
fun sum(values: LongArray): Long = values.sum()The corresponding conversions are:
Avoid |
Prefer |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Remediation
Replace Array<T> with the specialized TArray type and update the corresponding
constructor call (arrayOf(…) → intArrayOf(…), etc.).