[libgda/LIBGDA_5.2] Value: return 'NULL' for null/invalid values

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 295fa78d29eee6dbbc5d07fd6884cb95f48d92e0
Author: Daniel Espinosa <esodan gmail com>
Date:   Thu May 2 11:04:44 2019 -0500

    Value: return 'NULL' for null/invalid values
    
    GdaGeometric, short and Timestamp, when fail to get value, now
    return 'NULL' string.
    
    Fix https://gitlab.gnome.org/GNOME/libgda/issues/186

 libgda/gda-value.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/libgda/gda-value.c b/libgda/gda-value.c
index 7ad7dcfad..ff1445ef5 100644
--- a/libgda/gda-value.c
+++ b/libgda/gda-value.c
@@ -634,9 +634,7 @@ geometric_point_to_string (const GValue *src, GValue *dest)
                str = g_strdup_printf ("(%.*g,%.*g)", DBL_DIG, point->x,
                                       DBL_DIG, point->y);
        else
-               str = g_strdup_printf ("(%.*g,%.*g)",
-                                      DBL_DIG, 0.,
-                                      DBL_DIG, 0.);
+               str = g_strdup ("NULL");
        g_value_take_string (dest, str);
 }
 
@@ -1342,7 +1340,7 @@ timestamp_to_string (const GValue *src, GValue *dest)
                g_string_free (string, FALSE);
        }
        else
-               g_value_set_string (dest, "0000-00-00 00:00:00");
+               g_value_set_string (dest, "NULL");
 }
 
 GType
@@ -2898,7 +2896,7 @@ short_to_string (const GValue *src, GValue *dest)
        if (GDA_VALUE_HOLDS_SHORT (src))
                str = g_strdup_printf ("%d", gda_value_get_short ((GValue *) src));
        else
-               str = g_strdup_printf ("%d", gda_value_get_ushort ((GValue *) src));
+               str = g_strdup ("NULL");
 
        g_value_take_string (dest, str);
 }