static JSBool
context_to_g_argument(JSContext      *context,
                      jsval           value,
                      GITypeInfo     *type_info,
                      const char     *arg_name,
                      GjsArgumentType argument_type,
                      GITransfer      transfer,
                      gboolean        may_be_null,
                      GArgument      *arg)
{
    JSObject *obj;
    cairo_t *cr;

    obj = JSVAL_TO_OBJECT(value);
    cr = gjs_cairo_context_get_context(context, obj);
    if (!cr)
	return JS_FALSE;
    if (transfer == GI_TRANSFER_EVERYTHING)
        cairo_destroy(cr);

    arg->v_pointer = cr;
    return JS_TRUE;
}

The transfer == GI_TRANSFER_EVERYTHING check doens't make any sense for me. For background:

 * gjs_cairo_context_get_context() doesn't add a reference to the context

 * arg.c:type_needs_release() is false for any foreign type, as far as 
   I can see. So, we won't free in arguments after the function call.

So the code would look correct to me if it was:

    if (transfer == GI_TRANSFER_EVERYTHING)
        cairo_reference(cr);