tweak checks for display list zero

diff --git a/src/mesa/main/dlist.c b/src/mesa/main/dlist.c
index 4399385cc183c0cc98034e63e04cf832b59d80e5..8513b4580186ebeb31eae0a1c2b62d31164d7c07 100644 (file)
--- a/src/mesa/main/dlist.c
+++ b/src/mesa/main/dlist.c
@@ -4452,7 +4452,7 @@ execute_list( GLcontext *ctx, GLuint list )
    Node *n;
    GLboolean done;
 
-   if (!islist(ctx,list))
+   if (list == 0 || !islist(ctx,list))
       return;
 
    if (ctx->Driver.BeginCallList)
@@ -5354,6 +5354,11 @@ _mesa_CallList( GLuint list )
    if (MESA_VERBOSE & VERBOSE_API)
       _mesa_debug(ctx, "glCallList %d\n", list); 
 
+   if (list == 0) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "glCallList(list==0)");
+      return;
+   }
+
 /*     mesa_print_display_list( list ); */
 
    save_compile_flag = ctx->CompileFlag;