Re: [Qemu-devel] [PATCH] glib-compat: work around g_test_message bug with subprocess tests

[Marc-André Lureau]

On Tue, Nov 27, 2018 at 10:35 PM Paolo Bonzini <address@hidden> wrote:
>
> Subprocesses are created by glib without leaving the file descriptors
> open.  Therefore, g_test_message (and assertion failures, but those
> trigger when things are going bad anyway) will think that it is writing
> to the log file descriptor, but while actually stomping on the QMP
> file descriptor or similar.  This causes spurious failures, which are
> as nice to debug as the reader can imagine.  While I have opened a
> pull request on GLib, this will probably take a while to propagate
> to distros.
>
> I found this while working on qgraph, but the fix is generic.
>
> Signed-off-by: Paolo Bonzini <address@hidden>

good catch! makes me wonder if g_test_message() is supposed to be
usable in a subprocess.. Let see the review comments on upstream bug.
At least, documentation should be updated.

Reviewed-by: Marc-André Lureau <address@hidden>

> ---
>  include/glib-compat.h | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/include/glib-compat.h b/include/glib-compat.h
> index fdf95a2..989b9ef 100644
> --- a/include/glib-compat.h
> +++ b/include/glib-compat.h
> @@ -113,4 +113,10 @@ gint g_poll_fixed(GPollFD *fds, guint nfds, gint 
> timeout);
>
>  #pragma GCC diagnostic pop
>
> +/* See https://gitlab.gnome.org/GNOME/glib/merge_requests/501 */
> +#define g_test_message(...)                                                  
>   \
> +       do {                                                                  
>   \
> +               if (!g_test_subprocess()) g_test_message(__VA_ARGS__);        
>   \
> +       } while (0)
> +
>  #endif
> --
> 1.8.3.1
>