[gimp] g_return_if_fail() on attempts to set locks that can't be changed

[Michael Natterer <mitch src gnome org>]

commit 922375cecad12f1f0fe5d9bb1ea20be3cabffe6c
Author: Michael Natterer <mitch gimp org>
Date:   Sun Aug 23 19:54:19 2009 +0200

    g_return_if_fail() on attempts to set locks that can't be changed

 app/core/gimpitem.c  |    1 +
 app/core/gimplayer.c |    1 +
 2 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimpitem.c b/app/core/gimpitem.c
index 9a71966..16944cc 100644
--- a/app/core/gimpitem.c
+++ b/app/core/gimpitem.c
@@ -1611,6 +1611,7 @@ gimp_item_set_lock_content (GimpItem *item,
                             gboolean  push_undo)
 {
   g_return_if_fail (GIMP_IS_ITEM (item));
+  g_return_if_fail (gimp_item_can_lock_content (item));
 
   lock_content = lock_content ? TRUE : FALSE;
 
diff --git a/app/core/gimplayer.c b/app/core/gimplayer.c
index bb79e02..ebbaee9 100644
--- a/app/core/gimplayer.c
+++ b/app/core/gimplayer.c
@@ -2029,6 +2029,7 @@ gimp_layer_set_lock_alpha (GimpLayer *layer,
                            gboolean   push_undo)
 {
   g_return_if_fail (GIMP_IS_LAYER (layer));
+  g_return_if_fail (gimp_layer_can_lock_alpha (layer));
 
   lock_alpha = lock_alpha ? TRUE : FALSE;