AttributeError on determining field size

[treiher]

% tools/validate_spec.py -s dhcp.rflx -m DHCP::Message -v tests/data/dhcp/message/valid
tests/data/dhcp/message/valid/DHCP_MessageType_10,11,12_and_13_4.raw: FAILED
FalseNegative
pyrflx: error: cannot set value for field Htype
pyrflx: error: Number 0 is not a valid enum value

Traceback (most recent call last):
  File "tools/validate_spec.py", line 334, in <module>
    sys.exit(cli(sys.argv))
  File "tools/validate_spec.py", line 82, in cli
    validation_main(args)
  File "tools/validate_spec.py", line 135, in validation_main
    validation_result = validator.validate_message(msg)
  File "tools/validate_spec.py", line 200, in validate_message
    parser_result = self.__parse_message(original_message.bytes)
  File "tools/validate_spec.py", line 228, in __parse_message
    pdu_model.parse(message)
  File "[...]/lib/python3.7/site-packages/rflx/pyrflx/typevalue.py", line 736, in parse
    current_field_size = size.value
AttributeError: 'NoneType' object has no attribute 'value'

The used specification and test data can be found here.

@rssen Could you please take a look at it?

[rssen]

The problem is that Message'Last in the field condition of Options cannot be resolved into a Number. If I change the type of the Options field to Opaque it can be parsed successfully (at least there is not the particular error you described).

One option that comes to mind to resolve this, is to treat an Array field similar to an Opaque field for this matter so that it is not needed to explicitly evaluate the size of the field if the Message variable is present in the size expression.

When setting an Array field where the size cannot be resolved, the set_field_without_size function would be used. Therefore it is needed to ensure that the field is accessible by using the _is_valid_opaque_field method (rename) to enable that, because normally a field without a size would not be accessible and thus could not be set.

[treiher]

Sounds like a reasonable solution to me. As long as there are no major roadblocks to realization, let's do it that way.