Fix problems seen with some programs in the wild

* subcompositor.c (ViewAttachBuffer): Correctly determine when
to recompute view bounds.
* subsurface.c (AfterParentCommit): Unskip view first, and
commit pending state second.  Explain why.
* xdg_toplevel.c (Unmap, Map): Add new "initial configure" flag.
(Commit): Use it instead of testing current_buffer.  Explain
why.
(XLGetXdgToplevel): Set that flag by default.

subcompositor.c

@@ -1472,12 +1472,14 @@ ViewAttachBuffer (View *view, ExtBuffer *buffer)
   if (!view->buffer && old && view->subcompositor)
     /* The view needs a size update, as it is now 0 by 0.  */
     ViewAfterSizeUpdate (view);
-  else if (((buffer && !old)
+  else if ((buffer && !old)
 	    || (old && !buffer)
 	    || (buffer && old
 		&& (XLBufferWidth (buffer) != XLBufferWidth (old)
-		    || XLBufferHeight (buffer) != XLBufferHeight (old))))
+		    || XLBufferHeight (buffer) != XLBufferHeight (old))
-	   && !IsViewported (view))
+		/* Buffer width and height changes don't matter if the
+		   view has a viewport.  */
+		&& !IsViewported (view)))
     /* Recompute view and subcompositor bounds.  */
     ViewAfterSizeUpdate (view);
 

subsurface.c

@@ -600,6 +600,13 @@ AfterParentCommit (Surface *surface, void *data)
       MoveFractional (subsurface);
     }
 
+  /* Mark the subsurface as unskipped.  (IOW, make it visible).  This
+     must come before XLCommitSurface, as doing so will apply the
+     pending state, which will fail to update the subcompositor bounds
+     if the subsurface is skipped.  */
+  ViewUnskip (subsurface->role.surface->view);
+  ViewUnskip (subsurface->role.surface->under);
+
   /* And any cached surface state too.  */
   if (subsurface->pending_commit)
     {
@@ -610,10 +617,6 @@ AfterParentCommit (Surface *surface, void *data)
       MaybeUpdateOutputs (subsurface);
     }
 
-  /* Mark the subsurface as unskipped.  (IOW, make it visible).  */
-  ViewUnskip (subsurface->role.surface->view);
-  ViewUnskip (subsurface->role.surface->under);
-
   subsurface->pending_commit = False;
   subsurface->pending_substate.flags = 0;
 }

xdg_toplevel.c

@@ -54,6 +54,7 @@ enum
     StateDecorationModeDirty	    = (1 << 7),
     StateEverMapped		    = (1 << 8),
     StateNeedDecorationConfigure    = (1 << 9),
+    StateWaitingForInitialConfigure = (1 << 10),
   };
 
 enum
@@ -1164,7 +1165,7 @@ Unmap (XdgToplevel *toplevel)
 
   /* Clear all the state.  */
 
-  toplevel->state = 0;
+  toplevel->state = StateWaitingForInitialConfigure;
   toplevel->conf_reply = False;
   toplevel->conf_serial = 0;
   toplevel->states.size = 0;
@@ -1204,6 +1205,7 @@ Map (XdgToplevel *toplevel)
   SubcompositorGarbage (XLSubcompositorFromXdgRole (toplevel->role));
 
   toplevel->state |= StateIsMapped | StateEverMapped;
+  toplevel->state &= ~StateWaitingForInitialConfigure;
 
   /* Update the width and height from the xdg_surface bounds.  */
   toplevel->width = XLXdgRoleGetWidth (toplevel->role);
@@ -1268,8 +1270,16 @@ Commit (Role *role, Surface *surface, XdgRoleImplementation *impl)
       toplevel->state &= ~StatePendingMinSize;
     }
 
-  if (!surface->current_state.buffer)
+  if (!surface->current_state.buffer
+      /* Whenever any commit happens without the toplevel being
+	 mapped, send the initial configure event.  This is because
+	 some clients attach an initial 1x1 buffer and expect the
+	 compositor to do its thing.  */
+      || (toplevel->state & StateWaitingForInitialConfigure))
     {
+      /* Stop waiting for initial configure.  */
+      toplevel->state &= ~StateWaitingForInitialConfigure;
+
       /* No buffer was attached, unmap the window and send an empty
 	 configure event.  */
       if (toplevel->state & StateIsMapped)
@@ -2282,6 +2292,10 @@ XLGetXdgToplevel (struct wl_client *client, struct wl_resource *resource,
       return;
     }
 
+  /* Set this flag for some buggy clients.  See the comment above the
+     part of Commit that checks this flag for more details.  */
+  toplevel->state |= StateWaitingForInitialConfigure;
+
   toplevel->impl.funcs.attach = Attach;
   toplevel->impl.funcs.commit = Commit;
   toplevel->impl.funcs.detach = Detach;