Parse error on date fields containing dashes

[lblatchford]

Per MIL-STD-2500C CN2 section 5.1.7d (see https://gwg.nga.mil/ntb/baseline/docs/2500c/2500C.pdf) indicates that any portion of date and time fields that is not known may be populated with dashes. Currently such fields cause a parse error. Some examples:

Failed to convert: Parse Error: Failed to populate ImageSegment[1]. Cause: Parse Error: Unable to parse xs:dateTime from text: 201707--------
Schema context: ImageDateAndTime Location line 373 column 22 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430 limit(bytes) 1009
Schema context: sequence[1] Location line 154 column 8 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430Parse Error: Unable to parse xs:dateTime from text: 201707--------
Schema context: ImageDateAndTime Location line 373 column 22 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430 limit(bytes) 1009

Failed to convert: Parse Error: Failed to populate ImageSegment[1]. Cause: Parse Error: Unable to parse xs:dateTime from text: --------------
Schema context: ImageDateAndTime Location line 373 column 22 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430 limit(bytes) 1009
Schema context: sequence[1] Location line 154 column 8 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430Parse Error: Unable to parse xs:dateTime from text: --------------
Schema context: ImageDateAndTime Location line 373 column 22 in file:/root/DFDL_schemas/nitf.dfdl.xsd
Data location was preceding byte 430 limit(bytes) 1009

Test files are attached
nitf_2_1_date_field_dashes.zip