[gjs] Throw an exception when registering a GType that already exists

[Giovanni Campagna <gcampagna src gnome org>]

commit 0404112ea190bd3fd9ac6207f70a2bfb3ceddb14
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Thu Jun 21 18:49:17 2012 +0200

    Throw an exception when registering a GType that already exists
    
    The GType system only logs a warning in that case, and it can
    make bugs harder to track.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669350

 gi/object.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gi/object.c b/gi/object.c
index e710100..1b02fae 100644
--- a/gi/object.c
+++ b/gi/object.c
@@ -2292,6 +2292,11 @@ gjs_register_type(JSContext *cx,
     if (!do_base_typecheck(cx, parent, JS_TRUE))
         return JS_FALSE;
 
+    if (g_type_from_name(name) != G_TYPE_INVALID) {
+        gjs_throw (cx, "Type name %s is already registered", name);
+        return JS_FALSE;
+    }
+
     parent_priv = priv_from_js(cx, parent);
 
     if (!parent_priv)