Custom date decoding issue about swift-tagged HOT 5 CLOSED

Hi @buscarini! Thanks for the report and sorry about that! Do you have some code that illustrates the issue?

from swift-tagged.

Yes, I was preparing a pull request, but here you go:

func testDecodableCustomDates() {
    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .custom { decoder in
      let seconds = try decoder.singleValueContainer().decode(Int.self)
      return Date(timeIntervalSince1970: TimeInterval(seconds))
    }
    
    XCTAssertEqual(
      [Date(timeIntervalSince1970: 1)],
      try decoder.decode([Date].self, from: Data("[1]".utf8))
    )
    
    XCTAssertEqual(
      [Tagged<Tag, Date>(rawValue: Date(timeIntervalSince1970: 1))],
      try decoder.decode([Tagged<Tag, Date>].self, from: Data("[1]".utf8))
    )
  }

Unfortunately, I've found out that changing this back makes another test fail. In that case wrapped optionals fail to decode if the json value is null. I haven't been able to find a solution to both issues for now.

from swift-tagged.

@buscarini If I define decode as the following, both appear to work:

extension Tagged: Decodable where RawValue: Decodable {
  public init(from decoder: Decoder) throws {
    do {
      self.init(rawValue: try decoder.singleValueContainer().decode(RawValue.self))
    } catch {
      self.init(rawValue: try .init(from: decoder))
    }
  }
}

I'm not sure what the repercussions are, and it does indeed feel like a shortcoming or bug of Decodable. Any thoughts? Would we need to handle Encodable in a similar way?

from swift-tagged.

:D Funny, I just made a pull request with the same solution. I think this should work fine, and I think it's the only reasonable solution for now. I even checked swift source code, and it seems initializing the date with the decoder directly doesn't hit the date decoding strategy, as this is done by the decoder before getting to the actual type. And solving the optional issue with the singleValueContainer would require to have different code depending on the type, which shouldn't even be possible in a generic function.

As for the encodable protocol, I think it's going to have the same issue. I'll try to get some free time to put that in the pull request too.

from swift-tagged.

It seems that the encoding strategy doesn't require this, and just reverting the commit is enough to get it working.

from swift-tagged.