Warn about recursively calling size req wrappers on the same object and orientation

We are not re-entrant and there is no reason for widgets to
do this, most likely they'll just get unexpected bugs because
the wrappers may modify the request.

Computing the request should logically rely only on the
widget itself, not on any adjustments caused by set_size_request,
size groups, and so forth.

https://bugzilla.gnome.org/show_bug.cgi?id=628829

diff --git a/gtk/gtksizerequest.c b/gtk/gtksizerequest.c
index 7c67c7eab902289343726bdf38baadeb216b9754..827265ef29c965f6f769362fa548d222dc0dbdf1 100644 (file)
--- a/gtk/gtksizerequest.c
+++ b/gtk/gtksizerequest.c
@@ -155,6 +155,57 @@ do_size_request (GtkWidget      *widget,
   g_signal_emit_by_name (widget, "size-request", requisition);
 }
 
+#ifndef G_DISABLE_CHECKS
+static GQuark recursion_check_quark = 0;
+#endif /* G_DISABLE_CHECKS */
+
+static void
+push_recursion_check (GtkSizeRequest  *request,
+                      GtkSizeGroupMode orientation,
+                      gint             for_size)
+{
+#ifndef G_DISABLE_CHECKS
+  const char *previous_method;
+  const char *method;
+
+  if (recursion_check_quark == 0)
+    recursion_check_quark = g_quark_from_static_string ("gtk-size-request-in-progress");
+
+  previous_method = g_object_get_qdata (G_OBJECT (request), recursion_check_quark);
+
+  if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
+    {
+      method = for_size < 0 ? "get_width" : "get_width_for_height";
+    }
+  else
+    {
+      method = for_size < 0 ? "get_height" : "get_height_for_width";
+    }
+
+  if (previous_method != NULL)
+    {
+      g_warning ("%s %p: widget tried to gtk_size_request_%s inside "
+                 " GtkSizeRequest::%s implementation. "
+                 "Should just invoke GTK_SIZE_REQUEST_GET_IFACE(widget)->%s "
+                 "directly rather than using gtk_size_request_%s",
+                 G_OBJECT_TYPE_NAME (request), request,
+                 method, previous_method,
+                 method, method);
+    }
+
+  g_object_set_qdata (G_OBJECT (request), recursion_check_quark, (char*) method);
+#endif /* G_DISABLE_CHECKS */
+}
+
+static void
+pop_recursion_check (GtkSizeRequest  *request,
+                     GtkSizeGroupMode orientation)
+{
+#ifndef G_DISABLE_CHECKS
+  g_object_set_qdata (G_OBJECT (request), recursion_check_quark, NULL);
+#endif
+}
+
 static void
 compute_size_for_orientation (GtkSizeRequest    *request,
                               GtkSizeGroupMode   orientation,
@@ -207,6 +258,7 @@ compute_size_for_orientation (GtkSizeRequest    *request,
       /* Unconditional size request runs but is often unhandled. */
       do_size_request (widget, &requisition);
 
+      push_recursion_check (request, orientation, for_size);
       if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
         {
           requisition_size = requisition.width;
@@ -227,6 +279,7 @@ compute_size_for_orientation (GtkSizeRequest    *request,
             GTK_SIZE_REQUEST_GET_IFACE (request)->get_height_for_width (request, for_size, 
                                                                        &min_size, &nat_size);
         }
+      pop_recursion_check (request, orientation);
 
       if (min_size > nat_size)
         {