relates to:

• SR-5326 Decimal(string:locale:) doesn't fail when the entire string isn't parsable

Issue Description:

Decimal(string:locale) produces different results on macOS vs Linux. On macOS, it expects a localized decimal separator in the supplied string, whereas on Linux it expects the decimal separator to be "."

Steps to reproduce

import Foundation

let en_US = Locale(identifier: "en_US")
let fr_FR = Locale(identifier: "fr_FR")

var s = "1234.5678"
print("\(s) with en_US: \(Decimal(string: s, locale: en_US))")
print("\(s) with fr_FR: \(Decimal(string: s, locale: fr_FR))")

s = "1234,5678"
print("\(s) with en_US: \(Decimal(string: s, locale: en_US))")
print("\(s) with fr_FR: \(Decimal(string: s, locale: fr_FR))")

Output on macOS

1234.5678 with en_US: Optional(1234.5678)
1234.5678 with fr_FR: Optional(1234)
1234,5678 with en_US: Optional(1234)
1234,5678 with fr_FR: Optional(1234.5678)

Output on Linux

1234.5678 with en_US: Optional(1234.5678)
1234.5678 with fr_FR: Optional(1234.5678)
1234,5678 with en_US: Optional(1234)
1234,5678 with fr_FR: Optional(1234)

The API doc does not specify which behavior is correct. However, in my opinion, the macOS output is more correct since the initializer has a Locale parameter.

Environment

Linux

• Ubuntu 18.04 server

• Swift version 5.0 (swift-5.0-RELEASE) Target: x86_64-unknown-linux-gnu

macOS

• macOS 10.14.4

• Apple Swift version 5.0 (swiftlang-1001.0.69.5 clang-1001.0.46.3) Target: x86_64-apple-darwin18.5.0