[MacPorts] #40811: cairo: --enable-xcb-shm breaks many gtk3 apps since gtk3 3.10

[David Evans]

On 10/19/13 9:34 AM, MacPorts wrote:
> #40811: cairo: --enable-xcb-shm breaks many gtk3 apps since gtk3 3.10
> ----------------------+--------------------------
>  Reporter:  devans@…  |      Owner:  ryandesign@…
>      Type:  defect    |     Status:  new
>  Priority:  Normal    |  Milestone:
> Component:  ports     |    Version:  2.2.0
>  Keywords:  haspatch  |       Port:  cairo
> ----------------------+--------------------------
>  After the upgrade to gtk3 3.10.0, many gtk3 apps have begun to crash with
>  X11 protocol errors relating to the MIT SHM extension.
>
>  This has primarily been apparent in my GNOME-3 test branch but has also
>  been observed in at least one currently committed port, gnumeric. The
>  failures are generally in the context of image operations, particularly
>  those involving the display of GdkPixmaps (icons, thumbnails, etc).
>
>  To reproduce the problem with gnumeric:
>
>   * start gnumeric with default spreadsheet
>   * select Insert->Image...
>   * select an image file, e.g. JPEG, in the Select an Image window
>
>  The program immediately crashes (apparently trying to display the image
>  thumbnail) with the following on console:
>
>
>  {{{
>  (gnumeric:30071): Gdk-ERROR **: The program 'gnumeric' received an X
>  Window System error.
>  This probably reflects a bug in the program.
>  The error was 'BadAccess (attempt to access private resource denied)'.
>    (Details: serial 9061 error_code 10 request_code 132 minor_code 1)
>    (Note to programmers: normally, X errors are reported asynchronously;
>     that is, you will receive the error a while after causing it.
>     To debug your program, run it with the GDK_SYNCHRONIZE environment
>     variable to change this behavior. You can then get a meaningful
>     backtrace from your debugger if you break on the gdk_x_error()
>  function.)
>  Trace/BPT trap: 5
>  }}}
>
>  xdpyinfo shows:
>
>  $ xdpyinfo -queryExt | grep opcode | grep 132
>      MIT-SHM  (opcode: 132, base event: 72, base error: 132)
>
>  This problem only effects gtk+ 3.10.0 and later, versions 3.8.0 through
>  current version 3.8.6 work fine.
>
>  Although initial testing pointed to something that had changed in gtk3,
>  further testing shows that this is not a problem in gtk3 per se but is
>  related to internal issues in cairo involving the use of xcb-shm functions
>  which are enabled in the current cairo version.
>
>  Attached is a patch for cairo that fixes the immediate problem by
>  disabling the xcb-shm functions in configure. Further investigation is
>  probably warranted to understand why these functions are not working
>  properly.
>
>  For details of my journey down the gtk3 rabbit hole see
>  [https://bugzilla.gnome.org/show_bug.cgi?id=710319 gtk+ bug 710319]
>
Ryan --

Is it OK to go ahead and commit this?

Dave