MontePy cannot handle "read file" with only comments

[tjlaboss]

Bug Description

MontePy cannot process a read file=... target with only comments.

To Reproduce

montepy.read_input("problem.i")

Error Message

Details

Traceback (most recent call last):
  File "./load_problem.py", line 2, in <module>
    montepy.read_input("problem.i")
  File "./montepy/input_parser/input_reader.py", line 45, in read_input
    problem.parse_input(replace=replace)
    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "./montepy/mcnp_problem.py", line 434, in parse_input
    raise e
  File "./montepy/mcnp_problem.py", line 413, in parse_input
    obj = obj_parser(input)
  File "./montepy/mcnp_object.py", line 49, in wrapped
    add_line_number_to_exception(e, self)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "./montepy/exceptions.py", line 235, in add_line_number_to_exception
    raise error
  File "./montepy/mcnp_object.py", line 41, in wrapped
    return func(*args, **kwargs)
  File "./montepy/cell.py", line 144, in __init__
    super().__init__(input, self._parser, number)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "./montepy/mcnp_object.py", line 49, in wrapped
    add_line_number_to_exception(e, self)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "./montepy/exceptions.py", line 235, in add_line_number_to_exception
    raise error
  File "./montepy/mcnp_object.py", line 41, in wrapped
    return func(*args, **kwargs)
  File "./montepy/numbered_mcnp_object.py", line 60, in __init__
    super().__init__(input, parser)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "./montepy/mcnp_object.py", line 49, in wrapped
    add_line_number_to_exception(e, self)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "./montepy/exceptions.py", line 259, in add_line_number_to_exception
    raise error.with_traceback(trace)
  File "./montepy/mcnp_object.py", line 41, in wrapped
    return func(*args, **kwargs)
  File "./montepy/mcnp_object.py", line 137, in __init__
    raise ParsingError(
    ...<3 lines>...
    )
montepy.exceptions.ParsingError:     dummy.i, line 0

         1| c A 'read file' target containing just a comment
    dummy.i, line 0

         1| c A 'read file' target containing just a comment
The input ended prematurely.
sly: Parse error in input. EOF

MCNP input file snippet

problem.i:

Examle Problem
c Cells
1  0  -1  imp:n=1
read file=dummy.i
9  0  +1  imp:n=2

c Surfaces
1 so 1.0 

c Data
nps 1

dummy.i:

c A 'read file' target containing just a comment

Version

• Version 1.1.3

Additional context

Not a typical usage scenario.

[MicahGale]

... maybe don't do that.

[MicahGale]

Where should the comment go? Should it be attached to the other objects in the parent file? Or should it just disappear? I feel like dropping it would the easiest solution for now. I imagine the main use case is debugging and removing all objects in a file from the model.

[tjlaboss]

Location within the file: it should go where the READ card is (priority 3: make it pretty). Location in the objects: probably glued onto the padding node of the next object, as is done with other comments between objects.

Dropping it is also acceptable, even if only an interim solution (priority 2: make it valid).

The object behavior might change if #143 is implemented.

[MicahGale]

I think this and #143 might go hand in hand. The paradigm of having an orphaned comment... not great, but may be necessary. a comment only data block is (probably) valid.