There's a crash in static func stringBounds(_ string: Substr

<a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/us

Crash in Swift 5.7 when creating stringBounds error about expression HOT 4 CLOSED

nicklockwood commented on July 30, 2024

Crash in Swift 5.7 when creating stringBounds error

from expression.

Comments (4)

nicklockwood commented on July 30, 2024

@nighthawk I'm not able to reproduce the crash (I guess it's only on macOS 13 and above?) but can you confirm whether this works as a solution?

    static func stringBounds(_ string: Substring, _ index: String.Index) -> AnyExpression.Error {
        var _string = string.base
        while index > _string.endIndex {
            // Double the length until it fits
            // TODO: is there a better solution for this?
            _string += _string
        }
        let offset = _string.distance(from: string.startIndex, to: index)
        return stringBounds(String(string), offset)
    }

from expression.

nighthawk commented on July 30, 2024

Yep, the crash is on macOS 13 only, as far as I can tell. Your code fixes the crash, but the error messages all say that index 0 is invalid when it should be, say, -1 or -3.

from expression.

nicklockwood commented on July 30, 2024

What if you replace let offset = _string.distance(from: string.startIndex, to: index) with

let offset = index >= string.startIndex ?
            _string.distance(from: string.startIndex, to: index) :
            -_string.distance(from: index, to: string.startIndex)