[SR-14108] `DateFormatter` is not copied by `copy()` with SwiftFoundation.

[YOCKOW]

Previous ID	SR-14108
Radar	rdar://problem/73742491
Original Reporter	@YOCKOW
Type	Sub-task
Status	Resolved
Resolution	Done

Environment

Swift 5.3.2
Ubuntu 20.04

Additional Detail from JIRA

Votes	0
Component/s	Foundation
Labels	Sub-task
Assignee	@YOCKOW
Priority	Medium

md5: 18c43438b829dd3084a420779b428634

Parent-Task:

• SR-14908 Implement func copy() in subclasses of Formatter.

Issue Description:

DateFormatter.copy() returns the same instance not a copied one as you can see with following code:

import Foundation

let formatter: DateFormatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd"

print(formatter.string(from: Date()))
// Prints "2021-01-26"

let copiedFormatter = formatter.copy() as! DateFormatter
copiedFormatter.dateFormat = "yyyy/MM/dd"

print(formatter.string(from: Date()))
// Prints "2021-01-26" on Darwin
// Prints "2021/01/26" on non-Darwin

print(copiedFormatter.string(from: Date()))
// Prints "2021/01/26"

It may be caused by https://github.com/apple/swift-corelibs-foundation/blob/f17b5a25bbc604126a8c6aca8b0b75c2e0291a6c/Sources/Foundation/Formatter.swift#L60-L66

[typesanitizer]

@swift-ci create

[spevans]

Each subclass of Formatter needs to implement its own override of this method.

[YOCKOW]

Update this issue as a sub-task of SR-14908

[YOCKOW]

#3008

[YOCKOW]

Done in main branch.

Remaining:

• 5.5 branch: [5.5] SR-14108: Implement copy() in DateFormatter. #3010

• 5.4 branch: [5.4] SR-14108: Implement copy() in DateFormatter. #3011

[YOCKOW]

main: 0e4e031
5.5: 2d714e6
5.4: 8c439c5