[gnumeric] Set a nul length for graph series that contain just an error value.

[Jean Bréfort <jbrefort src gnome org>]

commit 019519d38f2d8c4dc9a5d31ecf97b90302d41db4
Author: Jean Brefort <jean brefort normalesup org>
Date:   Sun Apr 17 10:50:59 2016 +0200

    Set a nul length for graph series that contain just an error value.

 ChangeLog   |    5 +++++
 src/graph.c |    4 ++++
 2 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index da5533c..607cd0f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-04-17  Jean Brefort  <jean brefort normalesup org>
+
+       * src/graph.c (gnm_go_data_vector_load_len): return a nul length if the
+       value is an error.
+
 2016-03-22  Morten Welinder <terra gnome org>
 
        * configure.ac: Post-release bump.
diff --git a/src/graph.c b/src/graph.c
index 502cee7..448a64e 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -596,6 +596,10 @@ gnm_go_data_vector_load_len (GODataVector *dat)
                        vec->as_col = (vec->val->v_array.y > vec->val->v_array.x);
                        break;
                }
+               case VALUE_ERROR :
+                       new_len = 0;
+                       break;
+
                default :
                        new_len = 1;
                        vec->as_col = TRUE;