[records] equality on float / double components

Kevin Bourrillion kevinb at google.com
Wed Dec 6 18:22:56 UTC 2017

I'd strongly expect this to behave exactly as Float.equals() does. The
+0.0/-0.0 problem exists but is nothing new.

On Wed, Dec 6, 2017 at 1:07 PM, Brian Goetz <brian.goetz at oracle.com> wrote:

> It's time to play everyone's favorite game show, "What about NaN".
> If we have a record:
>     record Foo(float f);
> We would like Object.equals() to be reflexive, symmetric, and transitive.
> But if we define equals() in the obvious way (delegating to float==), then
> `new Foo(Float.NaN`) would not be equal to itself.
> If we delegate instead to `Float.compare(this.f, that.f)`, the NaN problem
> goes away (though comparison becomes modestly more expensive), but now +0
> and -0 are distinguished (== treats them the same.)

Kevin Bourrillion | Java Librarian | Google, Inc. | kevinb at google.com
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