Filed 32748795 On Tue, Jun 13, 2017 at 10:55 PM, David Hart <da...@hartbit.com> wrote:
> Worth a radar to improve docs. > > On 13 Jun 2017, at 22:12, Jens Persson via swift-users < > swift-users@swift.org> wrote: > > Thanks! > > The documentation that Xcode displays (for CharacterSet's > hasMember(inPlane plane:)) is as follows: > > Declaration: > func hasMember(inPlane plane: UInt8) -> Bool > > Description: > Returns true if the `CharacterSet` has a member in the specified plane. > This method makes it easier to find the plane containing the members of > the current character set. > The Basic Multilingual Plane (BMP) is plane 0. > > Parameters: > plane - No description > > Which is about the same as here: > https://developer.apple.com/documentation/foundation/ > characterset/1779728-hasmember > and here: > https://developer.apple.com/documentation/foundation/ > nscharacterset/1412406-hasmemberinplane > > No where does it mention anything about undefined behavior for some values > of plane. > > In order to find that crucial info, I'd have to do what you did, write it > in Objective C and dig through the stack trace, or just guess that it calls > CFCharacterSetHasMemberInPlane and that its documentation contains very > valuable pieces of information that for some reason got lost on the way to > NSCharacterSet's method hasMemberInPlane ... > > Kind of makes one wonder what other undocumented undefined behavior might > hide in Foundation and other places. > > /Jens > > > > > On Tue, Jun 13, 2017 at 7:14 PM, Doug Hill via swift-users < > swift-users@swift.org> wrote: > >> I tried your calls to NSFont in Objective-C, and it also crashes. Looking >> at the stack trace, I see that it crashes in CFCharacterSetHasMemberInPlane. >> I see documentation for thePlane parameter of this function says: >> >> The valid value range is from 0 to 16. If the value is outside of the >> valid plane number range, the behavior is undefined. >> >> I guess randomly crashing counts as undefined behavior. >> While it would be great if this function was more robust, Apple is >> definitely saying Don’t Do That. >> >> Doug Hill >> https://github.com/djfitz/SFFontFeatures >> >> >> On Jun 13, 2017, at 9:42 AM, Jens Persson via swift-users < >> swift-users@swift.org> wrote: >> >> PS >> There are only 17 planes in the (current?) Unicode standard, but I'm >> assuming that the CharacterSet.hasMember(inPlane:) shouldn't (randomly?) >> crash for UInt8 values other than 0 ... 16? >> It also seems strange that it reproducibly crashes or not depending on >> which specific font I use. >> >> >> On Tue, Jun 13, 2017 at 4:00 PM, Jens Persson <j...@bitcycle.com> wrote: >> >>> The below program demonstrates a possible bug that I encountered. >>> Can anyone else reproduce my results (as explained in the comments)? >>> If so, is it a Swift or Cocoa bug (I haven't tried it in Objective C)? >>> >>> import AppKit >>> >>> extension NSFont { >>> var planesWithMembers: [UInt8] { >>> return (UInt8(0) ... UInt8(255)).filter { >>> // The follwing line will crash (EXC_BAD_ACCESS) for some >>> fonts: >>> coveredCharacterSet.hasMember(inPlane: $0) >>> // I have tested it with Xcode 8.3.3 and Xcode 9 beta 1, both >>> // Swift 3 and 4, and they all reproduce the crash. >>> // macOS 10.12.5 >>> } >>> } >>> } >>> >>> // Examples that will not cause the crash: >>> // let fontName = "AlBayan" >>> // let fontName = "AppleBraille" >>> // let fontName = "Chalkboard" >>> // let fontName = "Helvetica" >>> // let fontName = "Zapfino" >>> >>> // Examples that will cause the crash: >>> // let fontName = "AppleColorEmoji" >>> // let fontName = "AppleSymbols" >>> let fontName = "Baskerville" >>> // let fontName = "Geneva" >>> // let fontName = "SnellRoundhand" >>> >>> let font = NSFont(name: fontName, size: 12)! >>> let result = font.planesWithMembers >>> print("Planes that contains members:", result) >>> >>> >> _______________________________________________ >> swift-users mailing list >> swift-users@swift.org >> https://lists.swift.org/mailman/listinfo/swift-users >> >> >> >> _______________________________________________ >> swift-users mailing list >> swift-users@swift.org >> https://lists.swift.org/mailman/listinfo/swift-users >> >> > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users > > >
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