Decimal's nextUp and nextDown ignore precision

[wongzigii (Zigii Wong)]

let decimal = Decimal(string: "0.000499")
decimal.nextUp  //  0.000500
decimal.nextUp  //  0.000600

The least representable value that compares greater than this value.

Why decimal's nextUp is ignoring the precision?

Expect:

let decimal = Decimal(string: "0.000499")
decimal.nextUp  //  0.000500
decimal.nextUp  //  0.000501

What extra work I need to do at this case?

[Martin (Martin R)]

Possible bugs of Decimal.ulp and Decimal.nextUp were mentioned here:

Why is Decimal.ulp greater than any decimal value itself?

Trying to find the number of decimals in a decimal number, I tried this in a REPL: 39> Decimal(0.01) > Decimal(1.0) $R28: Bool = false 40> Decimal(0.01).ulp $R29: Decimal = 0.010000 41> Decimal(0.01).ulp > Decimal(1.0) $R30: Bool = true This doesn't seem to work as expected. In fact, the ulp of even a small Decimal number, or a number with many decimal places, will still be larger than a very large Decimal number with no decimal places: 105> Decimal(string: "1.01")!.ulp > Decimal(string:…

[xwu (Xiaodi Wu)]

I fixed this for the open-source version (swift-corelibs-foundation) but Apple hasn’t picked up the changes for the proprietary version shipped on their platforms

[filip-sakel]

Maybe compatibility tests with Darwin, that should fail, could draw attention this issue.

[wongzigii (Zigii Wong)]

Is there any workaround for now ?

[xwu (Xiaodi Wu)]

I suppose you could copy and paste the corrected code into your own project.