WINGs/wayland: prevent infinite redisplay recursion during resize

The font prefs panel crashed because wl_resize called wl_redisplay
while already inside a redisplay. This caused expose handlers to
trigger more resizes, creating unbounded recursion and memory growth
(backing images growing to 1024+ pixels wide). Skip the redisplay
from wl_resize when wl_redisplay_depth > 0 — the ongoing parent
redisplay will composite the resized child at its new size.

WINGs/wview_wl.c

@@ -365,7 +365,10 @@ static void wl_resize(void *vctx, W_View *view, unsigned int w, unsigned int h)
 			cev._view_target = view->parent;
 			WMHandleEvent(&cev);
 		}
-		wl_redisplay(vctx, view);
+		/* Only redisplay if not already inside a redisplay (prevents
+		 * infinite recursion when expose handlers trigger resizes). */
+		if (wl_redisplay_depth == 0)
+			wl_redisplay(vctx, view);
 	}
 }
 
@@ -478,6 +481,19 @@ static void wl_redisplay(void *vctx, W_View *view)
 	if (view->parent && view->size.width > 0 && view->size.height > 0) {
 		pixman_image_t *src = (pixman_image_t *)W_GetViewBacking(view->window);
 		pixman_image_t *dst = (pixman_image_t *)W_GetViewBacking(view->parent->window);
+		if (!src || !dst || !pixman_image_get_data(src) || !pixman_image_get_data(dst)) {
+			wwarning("wl_redisplay: BAD composite view=0x%lx size=%dx%d src=%p dst=%p"
+			         " src_data=%p dst_data=%p src_dim=%dx%d dst_dim=%dx%d",
+			         (unsigned long)view->window,
+			         view->size.width, view->size.height,
+			         (void*)src, (void*)dst,
+			         src ? (void*)pixman_image_get_data(src) : NULL,
+			         dst ? (void*)pixman_image_get_data(dst) : NULL,
+			         src ? pixman_image_get_width(src) : 0,
+			         src ? pixman_image_get_height(src) : 0,
+			         dst ? pixman_image_get_width(dst) : 0,
+			         dst ? pixman_image_get_height(dst) : 0);
+		}
 		if (src && dst && pixman_image_get_data(src) && pixman_image_get_data(dst)) {
 			int sw = pixman_image_get_width(src);
 			int sh = pixman_image_get_height(src);
@@ -488,10 +504,13 @@ static void wl_redisplay(void *vctx, W_View *view)
 			/* Clip to destination bounds */
 			if (view->pos.x + cw > dw) cw = dw - view->pos.x;
 			if (view->pos.y + ch > dh) ch = dh - view->pos.y;
-			if (cw > 0 && ch > 0 && view->pos.x >= 0 && view->pos.y >= 0)
+			if (cw > 0 && ch > 0 && view->pos.x >= 0 && view->pos.y >= 0) {
+				fprintf(stderr, "COMPOSITE view=0x%lx pos=%d,%d cw=%d ch=%d sw=%d sh=%d dw=%d dh=%d\n",
+				        (unsigned long)view->window, view->pos.x, view->pos.y, cw, ch, sw, sh, dw, dh);
 				pixman_image_composite32(PIXMAN_OP_OVER, src, NULL, dst,
 					0, 0, 0, 0,
 					view->pos.x, view->pos.y, cw, ch);
+			}
 		}
 	}