Unpacking fails with the error invalidArgument in Swift 3

[Isuru-Nanayakkara]

Hi,

I'm encountering an issue unpacking a msgpack payload in Swift 3.

I'm getting a msgpack payload from an API and I'm using this library to unpack it. It used to work perfectly fine back in Swift 2 with the v1.2. I have created a sample payload as a byte array below.

do {
    let arr: [UInt8] = [133, 164, 99, 111, 100, 101, 162, 79, 75, 164, 100, 97, 116, 97, 132, 171, 97, 99, 99, 101, 115, 115, 84, 111, 107, 101, 110, 218, 1, 60, 101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 73, 85, 122, 73, 49, 78, 105, 73, 115, 73, 110, 82, 53, 99, 67, 73, 54, 73, 107, 112, 88, 86, 67, 74, 57, 46, 101, 121, 74, 106, 98, 71, 108, 108, 98, 110, 81, 105, 79, 105, 74, 109, 78, 50, 89, 121, 78, 84, 108, 107, 89, 83, 49, 104, 78, 122, 82, 108, 76, 84, 82, 109, 78, 50, 81, 116, 79, 87, 85, 52, 79, 67, 48, 50, 90, 68, 89, 52, 77, 122, 89, 120, 90, 106, 107, 51, 78, 84, 103, 105, 76, 67, 74, 119, 90, 88, 74, 122, 98, 50, 52, 105, 79, 105, 74, 105, 77, 84, 82, 119, 98, 110, 90, 48, 98, 109, 53, 122, 97, 106, 99, 120, 99, 122, 86, 122, 99, 50, 70, 104, 90, 121, 73, 115, 73, 109, 82, 108, 100, 109, 108, 106, 90, 83, 73, 54, 73, 107, 81, 53, 82, 68, 100, 71, 81, 122, 99, 49, 76, 84, 73, 52, 78, 85, 89, 116, 78, 69, 70, 68, 82, 83, 48, 53, 82, 84, 77, 53, 76, 84, 65, 120, 79, 84, 81, 122, 78, 106, 104, 66, 77, 106, 107, 122, 81, 121, 73, 115, 73, 110, 82, 53, 99, 71, 85, 105, 79, 106, 73, 115, 73, 109, 86, 52, 99, 67, 73, 54, 77, 84, 81, 52, 77, 84, 73, 50, 77, 106, 73, 51, 77, 83, 119, 105, 97, 88, 78, 122, 73, 106, 111, 105, 84, 87, 57, 114, 98, 121, 49, 84, 90, 88, 74, 50, 97, 87, 78, 108, 73, 110, 48, 46, 103, 80, 99, 81, 120, 68, 65, 76, 119, 85, 105, 117, 57, 95, 110, 79, 80, 97, 114, 65, 71, 104, 45, 106, 71, 106, 119, 88, 83, 84, 54, 107, 118, 74, 76, 87, 105, 98, 107, 107, 100, 75, 89, 169, 101, 120, 112, 105, 114, 101, 115, 65, 116, 206, 88, 74, 68, 191, 166, 112, 101, 114, 115, 111, 110, 136, 169, 102, 105, 114, 115, 116, 78, 97, 109, 101, 165, 73, 115, 117, 114, 117, 166, 104, 97, 110, 100, 108, 101, 160, 162, 105, 100, 180, 98, 49, 52, 112, 110, 118, 116, 110, 110, 115, 106, 55, 49, 115, 53, 115, 115, 97, 97, 103, 168, 105, 109, 97, 103, 101, 85, 114, 108, 160, 170, 108, 97, 115, 116, 65, 99, 116, 105, 118, 101, 206, 88, 73, 169, 165, 168, 108, 97, 115, 116, 78, 97, 109, 101, 171, 78, 97, 110, 97, 121, 97, 107, 107, 97, 114, 97, 165, 112, 104, 111, 110, 101, 172, 43, 57, 52, 55, 55, 49, 51, 53, 52, 56, 53, 54, 168, 116, 104, 117, 109, 98, 85, 114, 108, 160, 172, 114, 101, 102, 114, 101, 115, 104, 84, 111, 107, 101, 110, 218, 1, 60, 101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 73, 85, 122, 73, 49, 78, 105, 73, 115, 73, 110, 82, 53, 99, 67, 73, 54, 73, 107, 112, 88, 86, 67, 74, 57, 46, 101, 121, 74, 106, 98, 71, 108, 108, 98, 110, 81, 105, 79, 105, 74, 109, 78, 50, 89, 121, 78, 84, 108, 107, 89, 83, 49, 104, 78, 122, 82, 108, 76, 84, 82, 109, 78, 50, 81, 116, 79, 87, 85, 52, 79, 67, 48, 50, 90, 68, 89, 52, 77, 122, 89, 120, 90, 106, 107, 51, 78, 84, 103, 105, 76, 67, 74, 119, 90, 88, 74, 122, 98, 50, 52, 105, 79, 105, 74, 105, 77, 84, 82, 119, 98, 110, 90, 48, 98, 109, 53, 122, 97, 106, 99, 120, 99, 122, 86, 122, 99, 50, 70, 104, 90, 121, 73, 115, 73, 109, 82, 108, 100, 109, 108, 106, 90, 83, 73, 54, 73, 107, 81, 53, 82, 68, 100, 71, 81, 122, 99, 49, 76, 84, 73, 52, 78, 85, 89, 116, 78, 69, 70, 68, 82, 83, 48, 53, 82, 84, 77, 53, 76, 84, 65, 120, 79, 84, 81, 122, 78, 106, 104, 66, 77, 106, 107, 122, 81, 121, 73, 115, 73, 110, 82, 53, 99, 71, 85, 105, 79, 106, 69, 115, 73, 109, 86, 52, 99, 67, 73, 54, 77, 84, 99, 53, 77, 106, 73, 49, 79, 84, 65, 51, 77, 83, 119, 105, 97, 88, 78, 122, 73, 106, 111, 105, 84, 87, 57, 114, 98, 121, 49, 84, 90, 88, 74, 50, 97, 87, 78, 108, 73, 110, 48, 46, 85, 50, 113, 81, 109, 50, 99, 111, 95, 101, 67, 120, 77, 56, 102, 68, 82, 116, 65, 105, 53, 72, 87, 117, 121, 103, 98, 110, 73, 88, 119, 112, 77, 87, 84, 95, 117, 87, 88, 55, 48, 100, 69, 171, 100, 101, 115, 99, 114, 105, 112, 116, 105, 111, 110, 178, 82, 101, 113, 117, 101, 115, 116, 32, 115, 117, 99, 99, 101, 115, 115, 102, 117, 108, 167, 109, 101, 115, 115, 97, 103, 101, 178, 82, 101, 113, 117, 101, 115, 116, 32, 115, 117, 99, 99, 101, 115, 115, 102, 117, 108, 167, 115, 117, 99, 99, 101, 115, 115, 195]

    let data = Data(bytes: arr, count: arr.count)
    let msgpack = try unpack(data)
    print(msgpack)
} catch {
    print("Unpacking failed: \(error)")
}

Like I mentioned earlier, the unpacking happened successfully without error in Swift 2. I was using the v1.2 of this library. Here I tested it again with a sample Xcode 7.3 project.

When I converted the project to Swift 3 and upgraded the library to v2.0 and ran it against the same payload, it would fail with the error invalidArgument. I can't figure out why. All I could pin point was the error was occurring within the unpackString method.

I attached the Swift 3 converted Xcode 8 project as well. Same code. But the error occurs here.

[dilshank]

+1 facing the same problem

[Isuru-Nanayakkara]

I sifted through the pull requests and saw that this issue is already fixed. The problem is that the podspec file is not yet updated. So it's pulling the old source files with the issue when installed via CocoaPods. You'll have to update the version in the podspec file and this will go away. In the meantime I can install the library like this pod 'MessagePack.swift', :git => 'https://github.com/a2/MessagePack.swift.git', :branch => 'master'.

[a2]

Version 2.0.1 pushed. Please file a new issue if problem persists. Happy holidays 🎄

[Isuru-Nanayakkara]

All good now. Thanks! Happy holidays to you too!