Bug 672760 - Postponed transaction applied invalid date, causing segf…

…ault

upon opening data file.
Part 1: Prevent the crash by skipping instances with invalid dates.

src/gnome-utils/gnc-dense-cal.c

@@ -1736,14 +1736,20 @@ gdc_add_tag_markings(GncDenseCal *cal, guint tag)
     {
         dates[idx] = g_date_new();
         gnc_dense_cal_model_get_instance(cal->model, tag, idx, dates[idx]);
-    }
 
-    if (g_date_get_julian(dates[0]) < g_date_get_julian(calDate))
+    }
+    if (g_date_valid(dates[0]))
     {
-        _gnc_dense_cal_set_month(cal, g_date_get_month(dates[0]), FALSE);
-        _gnc_dense_cal_set_year(cal, g_date_get_year(dates[0]), FALSE);
+	 if (g_date_get_julian(dates[0]) < g_date_get_julian(calDate))
+	 {
+	      _gnc_dense_cal_set_month(cal, g_date_get_month(dates[0]), FALSE);
+	      _gnc_dense_cal_set_year(cal, g_date_get_year(dates[0]), FALSE);
+	 }
+    }
+    else
+    {
+	 g_warning("Bad date, skipped.");
     }
-
     gdc_mark_add(cal, tag, name, info, num_marks, dates);
 
     for (idx = 0; idx < num_marks; idx++)