User Profile

A couple of unit tests for an application failed on a iOS 17.2.1 device and I could break down the problem to some strange behaviour when applying a dictionary + DateComponents keys. The tests had been running fine with iOS 16.x Here is some simplified code to reproduce the behaviour in Playground: let date1 = try! Date("2023-12-31T00:00:00Z", strategy: .iso8601) let date2 = try! Date("2024-01-31T00:00:00Z", strategy: .iso8601) let date3 = try! Date("2024-02-28T00:00:00Z", strategy: .iso8601) let date1dc = Calendar.current.dateComponents([.year, .month], from: date1) let date2dc = Calendar.current.dateComponents([.year, .month], from: date2) let date3dc = Calendar.current.dateComponents([.year, .month], from: date3) let dc1 = DateComponents(year: 2023, month: 12) let dc2 = DateComponents(year: 2024, month: 01) let dc3 = DateComponents(year: 2024, month: 02) let data: [DateComponents: String] = [ dc1: "One", dc2: "Two", dc3: "Three" ] print(date1dc == dc1) print(date2dc == dc2) print(date3dc == dc3) print("--------------------------------") print(data[dc1]) print(data[dc2]) print(data[dc3]) print("--------------------------------") print(data[date1dc]) print(data[date2dc]) print(data[date3dc]) The output for date1dc, date2dc and date3dc now is random: true true true -------------------------------- Optional("One") Optional("Two") Optional("Three") -------------------------------- Optional("One") nil Optional("Three") or true true true -------------------------------- Optional("One") Optional("Two") Optional("Three") -------------------------------- nil nil nil or true true true -------------------------------- Optional("One") Optional("Two") Optional("Three") -------------------------------- nil nil Optional("Three") For me it looks like a serious foundation bug, but maybe I'm missing something.