[SR-7650] Incorrect result adding Decimals

[swift-ci]

Previous ID	SR-7650
Radar	None
Original Reporter	niftygrifty (JIRA User)
Type	Bug
Status	Closed
Resolution	Done

Environment

Linux / Swift 4.1

Additional Detail from JIRA

Votes	1
Component/s	Foundation
Labels	Bug
Assignee	@spevans
Priority	Medium

md5: 7c55bfb750d20ffab1a5ff97a6c5ad3a

Issue Description:

`Decimal(5538) + Decimal(2880.4)` results incorrectly in 1864.8.

`NSDecimalNumber(floatLiteral: 5538).adding(NSDecimalNumber(floatLiteral: 2880.4))` produces the same incorrect result.

[spevans]

#1550

[swift-ci]

Comment by David Monagle (JIRA)

Given the fact that this bug induces wildly incorrect results for a type that is the preferred option for currency calculations, shouldn't this be at least a high priority? This bug is in the current production release of Swift and will be affecting anybody running a production system.

[swift-ci]

Comment by Taylor Griffin (JIRA)

@spevans: Thank you for making a PR for this issue right away. I noticed it was just merged. Any idea about a timeline for a patch release? Attn: @admin

[spevans]

This was back ported to the 4.2 branch and has just been merged in #1588

[swift-ci]

Comment by David Monagle (JIRA)

So master (JIRA User) my understanding is that anybody using Decimal in production in 4.1.2 should rewrite their code to avoid the Decimal type or otherwise remove it from a production environment? 4.2 won’t be released until September.

[swift-ci]

Comment by Nicole Jacque (JIRA)

We've released Swift 4.1.3 which picks up the fix for this, and the snapshot is available on the swift.org downloads page.

[swift-ci]

Comment by David Monagle (JIRA)

Great result)