Re: Mac OS Sierra tab feature breaks C-x 5 2

[Anders Lindgren]

Yeah, I’m not sure about this either. It strikes me as a bit suspect,
but I don’t know that the alternatives are going to be any better.

We could disable the warning:

    #pragma clang diagnostic push
    #pragma clang diagnostic ignored "-Wobjc-method-access"
      if ([win respondsToSelector: @selector(setTabbingMode:)])
        [win setTabbingMode: NSWindowTabbingModeDisallowed];
    #pragma clang diagnostic pop

which is, I think, the right thing to do, but that’s quite messy
looking, and I suspect we’ll have to do the same for the gcc warning.
I don’t know if we’d then have to do some #ifdef stuff to separate the
clang and gcc stuff. This has the potential to get REALLY messy.

It's possible to encapsulate pragmas into preprocessor macros using the _Pragma construct. In fact, config.h contains similar stuff, c.f. _GL_INLINE_HEADER_BEGIN and _GL_INLINE_HEADER_END.

Another possibility is to cast `win` to `id`, which I’d guess would
look like:

    [(id)win setTabbingMode: NSWindowTabbingModeDisallowed];

I still get the same warning, so this is not a solution.

By the way, while digging around I came across a lot of stuff saying
address@hidden(setTabbingMode)` should give a warning if `setTabbingMode`
doesn’t exist. Are you seeing one?

No, no warning is issued about that.

I believe that there are a number of #ifdef:s that could be rewritten in this way, so we need something ergonomically. (If we could get rid of all such ifdef:s there would not be a need for OS-version specific binaries.)

Given the options, I would say that a solution along the lines of _GL_INLINE_HEADER_BEGIN would be best. The pros are:

* All the messy bits can be located in one place, and it can easily be updated to match future compiler versions. (Should some compiler start to warn about, say, address@hidden(setTabbingMode)`, that too could be incorporated in the macros.)

* There is a natural location to place documentation and to describe the situation

* In the code that use the macros, there is a signal to the reader that something special is going on

* It's possible to write formal tests, ensuring the macros work as intended.

Unlike _GL_INLINE_HEADER_BEGIN, we should not use a leading underscore, as such identifiers are reserved for the compiler itself. Maybe NS_SILENCE_MISSING_METHOD_WARNING_BEGIN and -_END? The end result would look like:

      NS_SILENCE_MISSING_METHOD_WARNING_BEGIN

      if ([win respondsToSelector: @selector(setTabbingMode:)])
        [win setTabbingMode: NSWindowTabbingModeDisallowed];
      NS_SILENCE_MISSING_METHOD_WARNING_END

    -- Anders