Re: [Qemu-devel] [PATCH v2] glib-compat: work around g_test_message bug with subprocess tests

[Paolo Bonzini]

On 29/11/18 19:00, Paolo Bonzini 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.

This is not a problem anymore if we switch from gtester to tap.  Do we
want it fixed anyway or not?

Paolo

> Signed-off-by: Paolo Bonzini <address@hidden>
> Message-Id: <address@hidden>
> Reviewed-by: Marc-André Lureau <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  include/glib-compat.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/glib-compat.h b/include/glib-compat.h
> index fdf95a255d..f675c7328f 100644
> --- a/include/glib-compat.h
> +++ b/include/glib-compat.h
> @@ -113,4 +113,12 @@ 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
>