[SR-2980] NSDecimalNumber's .intValue produces incorrect results for numbers with many numbers after the decimal place

[swift-ci]

Previous ID	SR-2980
Radar	None
Original Reporter	pwicks (JIRA User)
Type	Bug
Status	Reopened
Resolution

Environment

``` java $ swift --version Apple Swift version 3.0 (swiftlang-800.0.46.2 clang-800.0.38) Target: x86_64-apple-macosx10.9 $ sw_vers ProductName: Mac OS X ProductVersion: 10.11.6 BuildVersion: 15G1004 ``` XCode Version: Version 8.0 (8A218a)

Additional Detail from JIRA

| | | |------------------|-----------------| |Votes | 2 | |Component/s | Foundation | |Labels | Bug | |Assignee | None | |Priority | Medium | md5: edd4e608242098a65d37a036b1051abb

duplicates:

• SR-7236 NSDecimalNumber .intValue reporting 0 on numbers with many decimals

is duplicated by:

• SR-7236 NSDecimalNumber .intValue reporting 0 on numbers with many decimals
• SR-9025 Incorrect conversion of NSDecimalNumber to Int

Issue Description:

For NSDecimalNumbers with a lot of numbers after the decimal point, .intValue is always zero. Experimentally, it looks like the crossover point where .intValue becomes incorrect is around 19 places after the decimal point (but I haven't tested this extensively).

.int64Value has the same behavior. .int32Value, .int16Value and .int8Value do not.

Test Case:

var a = NSDecimalNumber(string: "103.8097165991902834008097165991902834")
a: NSDecimalNumber = {
  Foundation.NSNumber = {
    baseNSValue@0 = <extracting data from value failed>

  }
}
  6> a.intValue
$R2: Int = 0
  7> a.doubleValue
$R3: Double = 103.80971659919028
  8> a.int64Value
$R4: Int64 = 0
  9> a.int32Value
$R5: Int32 = 103
 10> a.int16Value
$R6: Int16 = 103
 11> a.int8Value
$R7: Int8 = 103
 12> var b = NSDecimalNumber(string: "1.1111111111111111111111111111111111111")
b: NSDecimalNumber = {
  Foundation.NSNumber = {
    baseNSValue@0 = <extracting data from value failed>

  }
}
 13> b.intValue
$R8: Int = 0
 14> b.int32Value
$R9: Int32 = 1

[swift-ci]

Comment by Fabian Emmes (JIRA)

I also noticed this bug, using Swift 3.0.1:

Apple Swift version 3.0.1 (swiftlang-800.0.58.6 clang-800.0.42.1)
Target: x86_64-apple-macosx10.9

And indeed it looks as if it depends on the number of decimal places:

 14> NSDecimalNumber(string: "250.229953885078403").int64Value
$R4: Int64 = 250
 15> NSDecimalNumber(string: "250.22995388507840317").int64Value 
$R5: Int64 = 65
 16> NSDecimalNumber(string: "250.2299538850784031744").int64Value 
$R6: Int64 = 0

[swift-ci]

Comment by Andrew Hoos (JIRA)

This seems to be resolved in top of tree master.

[martinr448]

The problem still exists in Swift 4.2 (Xcode 10):

Welcome to Apple Swift version 4.2 (swiftlang-1000.11.37.1 clang-1000.11.45.1). Type :help for assistance.
  1>  
  2> import Foundation
  3>  
  4> let a = NSDecimalNumber(string: "103.8097165991902834008097165991902834")
a: NSDecimalNumber = 3748538862552120946 x 10^-34
  5> a.int64Value
$R0: Int64 = 0

Another example:

  7> let b = NSDecimalNumber(string: "31.541176470588235294")
b: NSDecimalNumber = 13094432396878683678 x 10^-18
  8> b.int64Value
$R1: Int64 = -5
  9> b.uint64Value 
$R2: UInt64 = 13

[martinr448]

The wrong results can still be reproduced with Apple Swift version 4.2 (swiftlang-1000.11.37.1 clang-1000.11.45.1) that comes with Xcode 10, therefore I have reopened the issue.

[bealex]

Got this problem with current Swift 5.1.3 (Xcode 11.3.1)

[be0aadd9-8960-4c13-b27b-3298be9f43c2]

To reproduce on Swift 5.1.3:

$ swift -version
Apple Swift version 5.1.3 (swiftlang-1100.0.282.1 clang-1100.0.33.15)
Target: x86_64-apple-darwin19.3.0
$ swift
import Foundation
print((Decimal(string: "12345.12345678901234")! as NSDecimalNumber).intValue) 
12345
print((Decimal(string: "12345.123456789012345")! as NSDecimalNumber).intValue)
-6101

[spevans]

Linux fix: https://github.com/apple/swift-corelibs-foundation/pull/2925

[pietermuller]

To reproduce with Swift 5.7 on macOS:

$ swift -version
swift-driver version: 1.62.8 Apple Swift version 5.7 (swiftlang-5.7.0.127.4 clang-1400.0.29.50)
Target: arm64-apple-macosx12.0
$ swift repl
Welcome to Apple Swift version 5.7 (swiftlang-5.7.0.127.4 clang-1400.0.29.50).
Type :help for assistance.
  1> import Foundation 
  2> print((Decimal(string: "12345.12345678901234")! as NSDecimalNumber).intValue) 
12345
  3> print((Decimal(string: "12345.123456789012345")! as NSDecimalNumber).intValue)
-6101

[xjki]

Reproducable with Swift 5.9 on macOS:

~$ swift repl
Welcome to Apple Swift version 5.9 (swiftlang-5.9.0.128.108 clang-1500.0.40.1).
1> import Foundation
2> print((Decimal(string: "12345.12345678901234")! as NSDecimalNumber).intValue)
12345
3> print((Decimal(string: "12345.123456789012345")! as NSDecimalNumber).intValue)
-6101

[tcamin]

❯ swift repl
Welcome to Apple Swift version 5.9 (swiftlang-5.9.0.128.108 clang-1500.0.40.1).
Type :help for assistance.
  1> import Foundation
  2> let decimal = NSDecimalNumber(value: 10.12)
  3. decimal.intValue
$R0: Int = -8
decimal: NSDecimalNumber = 10119999999999997952 x 10^-18