[PATCH wayland] Revert "client: require WAYLAND_DISPLAY to be set"

[Peter Hutterer]

On Mon, Aug 17, 2015 at 04:17:57PM +0300, Pekka Paalanen wrote:
> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> 
> This reverts commit fb7e13021730d0a5516ecbd3712ea4235e05d24d.
> 
> Developers have been trying to reduce the number of by default required
> environment variables, and the mentioned commit is a step backwards in
> that sense. The fundamental assumption is that a user has only one main
> (Wayland) display server where all programs should connect to by
> default, and do so with an a priori known socket name.
> 
> The commit also broke various use cases in the wild, some accidentally
> due to other causes, some intentionally. This revert allows those use
> cases to continue.
> 
> The original problem of running Weston in a window in an existing GNOME
> X11 session and getting applications unintentionally launched into
> Weston can be circumvented by letting Weston use a non-default socket
> name, leaving wayland-0 unused.
> 
> Discussion:
> http://lists.freedesktop.org/archives/wayland-devel/2015-August/023927.html
> http://lists.freedesktop.org/archives/wayland-devel/2015-August/023937.html

not a big fan of it, but Acked-by: Peter Hutterer <peter.hutterer at who-t.net>

Cheers,
   Peter

> 
> Cc: Dima Ryazanov <dima at gmail.com>
> Cc: Giulio Camuffo <giuliocamuffo at gmail.com>
> Cc: Daniel Stone <daniel at fooishbar.org>
> Cc: Jasper St. Pierre <jstpierre at mecheye.net>
> Cc: Ryo Munakata <ryomnktml at gmail.com>
> Cc: Ray Strode <halfline at gmail.com>
> Cc: Peter Hutterer <peter.hutterer at who-t.net>
> Cc: Matthias Clasen <mclasen at redhat.com>
> Cc: Sjoerd Simons <sjoerd.simons at collabora.co.uk>
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> ---
>  doc/man/wl_display_connect.xml    |  5 +++--
>  doc/publican/sources/Protocol.xml |  8 ++++----
>  src/wayland-client.c              | 10 ++++------
>  3 files changed, 11 insertions(+), 12 deletions(-)
> 
> diff --git a/doc/man/wl_display_connect.xml b/doc/man/wl_display_connect.xml
> index ded3cbd..7e6e05c 100644
> --- a/doc/man/wl_display_connect.xml
> +++ b/doc/man/wl_display_connect.xml
> @@ -57,8 +57,9 @@
>            that was previously opened by a Wayland server. The server socket must
>            be placed in <envar>XDG_RUNTIME_DIR</envar> for this function to
>            find it. The <varname>name</varname> argument specifies the name of
> -          the socket or <constant>NULL</constant> to use the default
> -          (which is the value of <envar>WAYLAND_DISPLAY</envar>). If
> +          the socket or <constant>NULL</constant> to use the default (which is
> +          <constant>"wayland-0"</constant>). The environment variable
> +          <envar>WAYLAND_DISPLAY</envar> replaces the default value. If
>            <envar>WAYLAND_SOCKET</envar> is set, this function behaves like
>            <function>wl_display_connect_to_fd</function> with the file-descriptor
>            number taken from the environment variable.</para>
> diff --git a/doc/publican/sources/Protocol.xml b/doc/publican/sources/Protocol.xml
> index 9464953..477063b 100644
> --- a/doc/publican/sources/Protocol.xml
> +++ b/doc/publican/sources/Protocol.xml
> @@ -60,10 +60,10 @@
>      <title>Wire Format</title>
>      <para>
>        The protocol is sent over a UNIX domain stream socket, where the endpoint
> -      name is determined by the <emphasis>WAYLAND_DISPLAY</emphasis>
> -      environment variable.  Its value will usually be
> -      <systemitem class="service">wayland-0</systemitem>.  The protocol is message-based.
> -      A message sent by a client to the server is called request.  A message
> +      usually is named <systemitem class="service">wayland-0</systemitem>
> +      (although it can be changed via <emphasis>WAYLAND_DISPLAY</emphasis>
> +      in the environment).  The protocol is message-based.  A
> +      message sent by a client to the server is called request.  A message
>        from the server to a client is called event.  Every message is
>        structured as 32-bit words, values are represented in the host's
>        byte-order.
> diff --git a/src/wayland-client.c b/src/wayland-client.c
> index ffbca4b..09c594a 100644
> --- a/src/wayland-client.c
> +++ b/src/wayland-client.c
> @@ -764,11 +764,8 @@ connect_to_socket(const char *name)
>  
>  	if (name == NULL)
>  		name = getenv("WAYLAND_DISPLAY");
> -	if (name == NULL) {
> -		wl_log("error: WAYLAND_DISPLAY not set in the environment.\n");
> -		errno = ENOENT;
> -		return -1;
> -	}
> +	if (name == NULL)
> +		name = "wayland-0";
>  
>  	fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
>  	if (fd < 0)
> @@ -872,7 +869,8 @@ wl_display_connect_to_fd(int fd)
>   * \return A \ref wl_display object or \c NULL on failure
>   *
>   * Connect to the Wayland display named \c name. If \c name is \c NULL,
> - * its value will be replaced with the WAYLAND_DISPLAY environment variable.
> + * its value will be replaced with the WAYLAND_DISPLAY environment
> + * variable if it is set, otherwise display "wayland-0" will be used.
>   *
>   * \memberof wl_display
>   */
> -- 
> 2.4.6
>