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xi: Fix build on arch linux (cast between struct and union gcc error) 

Fixes this build error on arch linux:

../Xi/exevents.c:1394:26: error: array subscript ‘InternalEvent {aka union _InternalEvent}[0]’ is partly outside array bounds of ‘DeviceEvent[1]’ {aka ‘struct _DeviceEvent[1]’} [-Werror=array-bounds=]
 1394 |                 evtype = GetXI2Type(ev->any.type);
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~
../Xi/exevents.c: In function ‘DeliverEmulatedMotionEvent’:
../Xi/exevents.c:1571:17: note: object ‘motion’ of size 432
 1571 |     DeviceEvent motion;
      |

which happens because of change in build options compared to master and gcc 15.1 in arch. I think this warning (and error) is a bug in gcc.

gcc 15.1 doesn't like when struct DeviceEvent is cast to union InternalEvent.
InternalEvent has a union any type and DeviceEvent type and these have to have a matching structure (for the header part).
When the InternalEvent is used in RetrieveTouchDeliveryData function it access the any field, which accessed the data defined previously in the device_event fields.
This change matches how its done in touch.c TouchEmitTouchEnd for example and it's "more correct",
since we are no longer casting from a smaller struct (DeviceEvent) to a larger struct (InternalEvent) when calling RetrieveTouchDeliveryData.

Signed-off-by: dec05eba <dec05eba@protonmail.com>
This commit is contained in:
dec05eba 2025-06-06 16:41:35 +02:00 committed by Enrico Weigelt, metux IT consult
parent 8c3c20f3fe
commit 2f66431927
1 changed files with 8 additions and 8 deletions
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16
Xi/exevents.c
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@ -1568,7 +1568,7 @@ static void
DeliverEmulatedMotionEvent(DeviceIntPtr dev, TouchPointInfoPtr ti, DeliverEmulatedMotionEvent(DeviceIntPtr dev, TouchPointInfoPtr ti,
InternalEvent *ev) InternalEvent *ev)
{ {
DeviceEvent motion; InternalEvent motion;
if (ti->num_listeners) { if (ti->num_listeners) {
ClientPtr client; ClientPtr client;
@ -1580,27 +1580,27 @@ DeliverEmulatedMotionEvent(DeviceIntPtr dev, TouchPointInfoPtr ti,
ti->listeners[0].type != TOUCH_LISTENER_POINTER_GRAB) ti->listeners[0].type != TOUCH_LISTENER_POINTER_GRAB)
return; return;
motion = ev->device_event; motion.device_event = ev->device_event;
motion.type = ET_TouchUpdate; motion.device_event.type = ET_TouchUpdate;
motion.detail.button = 0; motion.device_event.detail.button = 0;
if (!RetrieveTouchDeliveryData(dev, ti, (InternalEvent*)&motion, if (!RetrieveTouchDeliveryData(dev, ti, &motion,
&ti->listeners[0], &client, &win, &grab, &ti->listeners[0], &client, &win, &grab,
&mask)) &mask))
return; return;
DeliverTouchEmulatedEvent(dev, ti, (InternalEvent*)&motion, &ti->listeners[0], client, DeliverTouchEmulatedEvent(dev, ti, &motion, &ti->listeners[0], client,
win, grab, mask); win, grab, mask);
} }
else { else {
InternalEvent button; InternalEvent button;
int converted; int converted;
converted = TouchConvertToPointerEvent(ev, (InternalEvent*)&motion, &button); converted = TouchConvertToPointerEvent(ev, &motion, &button);
BUG_WARN(converted == 0); BUG_WARN(converted == 0);
if (converted) if (converted)
ProcessOtherEvent((InternalEvent*)&motion, dev); ProcessOtherEvent(&motion, dev);
} }
} }