@NullMarked with record constructor validation bug?
已回答
Hello
Is this a bug? I intend to use NullMarked to tell users of this class that the fields are non-null, but I want to do validation in the constructor. When i do that it says the condition is always false.
Thanks,
Logan
请先登录再写评论。
means all reference types are non-null by default. So IntelliJ assumes latitude, longitude, and heading can never be null, which makes:
if (latitude == null)
always false by contract.
How to do validation correctly:
If you want to validate inputs, mark the constructor parameters as nullable:
public record BusCoordinates(
BigDecimal latitude,
BigDecimal longitude,
Integer heading
) {
public BusCoordinates(
@Nullable BigDecimal latitude,
@Nullable BigDecimal longitude,
@Nullable Integer heading
) {
this.latitude = Objects.requireNonNull(latitude, "latitude must not be null");
this.longitude = Objects.requireNonNull(longitude, "longitude must not be null");
this.heading = Objects.requireNonNull(heading, "heading must not be null");
}
}
This keeps:
fields non-null (API guarantee)
constructor validation meaningful