icalvalue: return "" for NO_VALUE if ALLOW_EMPTY_PROPERTIES=true

Author: brong

Diff for: src/libical/icalproperty.c

@@ -349,6 +349,11 @@ const char *icalproperty_as_ical_string(icalproperty *prop)
     char *buf;
 
     buf = icalproperty_as_ical_string_r(prop);
+#if ICAL_ALLOW_EMPTY_PROPERTIES
+    /* empty string is set to no-value, per commit b1a9eb33597028b2d160f289b6105f4aa67276a7
+     * which return NULL as the string value.  Convert back to an empty string here */
+    if (!buf) return "";
+#endif
     icalmemory_add_tmp_buffer(buf);
     return buf;
 }

Diff for: src/libical/icalvalue.c

@@ -1247,7 +1247,14 @@ char *icalvalue_as_ical_string_r(const icalvalue *value)
     case ICAL_NO_VALUE:
     default:
         {
+#if ICAL_ALLOW_EMPTY_PROPERTIES
+            /* empty string is set to no-value, per
+             * commit b1a9eb33597028b2d160f289b6105f4aa67276a7
+             * Convert back to an empty string here */
+            return icalmemory_strdup("");
+#else
             return 0;
+#endif
         }
     }
 }