Fixed Exclusive Access to Memory bug

[SandorDobi]

The last swift snapshot (2018-02-08) start to enforce the Exclusive Access to Memory (SE-0176) this cause to fail to build vapor Validation sources.
This PR is fixing that.

[tanner0101]

we need to avoid !

[SandorDobi]

Yep but that is already safe because of conditional binding, if it is nil then the whole block is skipped....

[siemensikkema]

@SandorDobi you're totally right that it is safe in this case but we like to avoid it out of principle. @martinlasek will provide an alternative in 1, 2, 3 .. ;)

[martinlasek]

One way to solve it without having to force unwrap could be:

var reason: String {
    if let left = left, let right = right {
        var mutableLeft = left, mutableRight = right
        mutableLeft.codingPath = codingPath + left.codingPath
        mutableRight.codingPath = codingPath + right.codingPath
        return "\(mutableLeft.reason) and \(mutableRight.reason)"
    } else if let left = left {
        var mutableLeft = left
        mutableLeft.codingPath = codingPath + left.codingPath
        return mutableLeft.reason
    } else if let right = right {
        var mutableRight = right
        mutableRight.codingPath = codingPath + right.codingPath
        return mutableRight.reason
    } else {
        return ""
    }
}

[SandorDobi]

Yep. Sure. I have a rule to avoid temporary variables where it is don't needed.

but understand if You have a strict "no !" policy.
So I'll change PR.

[martinlasek]

Maybe we can go a consistent way here with a prefix mutable and do it in all the places as well without the bang. Like for this:

var reason: String {
    return errors.map { error in
        var mutableError = error
        mutableError.codingPath = codingPath + error.codingPath
        return mutableError.reason
    }.joined(separator: ", ")
}

[martinlasek]

One way to solve it without having to force unwrap could be:

var reason: String {
    if let left = left, let right = right {
        var mutableLeft = left, mutableRight = right
        mutableLeft.codingPath = codingPath + left.codingPath
        mutableRight.codingPath = codingPath + right.codingPath
        return "\(mutableLeft.reason) and \(mutableRight.reason)"
    } else if let left = left {
        var mutableLeft = left
        mutableLeft.codingPath = codingPath + left.codingPath
        return mutableLeft.reason
    } else if let right = right {
        var mutableRight = right
        mutableRight.codingPath = codingPath + right.codingPath
        return mutableRight.reason
    } else {
        return ""
    }
}

[martinlasek]

That approach feels nice 👍

[martinlasek]

Attention indentation. 😊

[SandorDobi]

Done. Crappy Xcode allways do me some quirks