Indentation wrong for Functions/Procedures Without Arguments

[obruendl]

Environment Ubuntu 20.04

Describe the bug

VSG seems unable to handle procedure without arguments - indentation was messed up in this case. I worked around this by adding an ugly "dummy" parameter. Could you check if it can be configured to accept this case? Probably it is a problem with the indentation rules. Example here

It's of course possible that this somehow has to do with my indent configuration. You can find my config file here

To Reproduce

1. Checkout Open-Logic (develop branch)
2. remove the "dummy workaround" from olo_test_2c_vc.vhd
3. Run vsg on the file ("vsg -c ./lint/config/vsg_config.yml ./lint/config/vsg_config_overlay_vc.yml -f olo_test_2c_vc.vhd)

Regarding the "vsg_config_overlay_vc": This is required beause I have different coding rules for verification components and my main codebase. See Open-Logic documentation for details.

Expected behavior Indentation for the function without arguments should be "sane". However, I see that indentation after the function header is messed up (more inidentation than I would expect). Should be rather obvious - if not, feel free to check back with me.

Screenshots None

Additional context None

[JHertz5]

Hi @obruendl. Thanks for raising this issue. I will try to take a look soon. The config file that you've referenced is > 4k lines long. If you would be able to provide a minimal reproducible example, i.e. a minimal config file that demonstrates your problem, it would help us to investigate this more quickly.

[obruendl]

See attached example.

test_case.zip

[JHertz5]

Hi @obruendl. Thanks very much, that's helped a lot! With your MRE, I'm able to easily reproduce your problem.

Your snippet with default config ($ vsg -f test_pkg.vhd --fix)

package olo_base_pkg_math is

  function log2 return natural;

end package olo_base_pkg_math;

package body olo_base_pkg_math is

  function log2 return natural is
  begin

    return 3;

  end function log2;

end package body olo_base_pkg_math;

Your snippet with the custom config ($ vsg -f test_pkg.vhd -c vsg_test.yml --fix)

package olo_base_pkg_math is

  function log2 return natural;

  end package olo_base_pkg_math;

  package body olo_base_pkg_math is

    function log2 return natural is
      begin

        return 3;

      end function log2;

    end package body olo_base_pkg_math;

I can see that after the function specification with no parameter list, the indent level increases, and I can see that this does not occur if there is a parameter list in the function specification.

The relevant portion of the custom config file is as follows:

indent:
    tokens:
        function_specification:
            function_keyword:
                token: current
                after: "+2"
            close_parenthesis:
                token: "-1"
                after: "-1"

I've taken a look and I can see the source of this problem. As I'm sure you know, this config tells VSG how to indent different tokens in the code. In this instance, VSG is being told, when there is a function keyword within a function specification, change the indent level from the line after by +2, and when there is a ) within a function specification, change the indent level by -1 on the same line by -1 and by another -1 from the line after.

Therefore, if there is a function specification with a parameter list, the function keyword increases the indent level by 2, but the ) of the parameter list subtracts 2 and the indent level after the function specification is back to normal. However, if the parameter list is not there, the function keyword increases the indent level by 2, but there is no ) of the parameter list to counteract this, so the indent level after the function specification is changed. Here's an example:

  -- indent level X
  function log2 (value : integer) return natural;
  -- indent level X+2-1-1 = X

  -- indent level X
  function log2 return natural;
    --indent level X+2

So the problem is that there is a +2 indent, following by a token (which is optional) that is expected to reduce the indent back down.

If you use the default indent config:

indent:
    tokens:
        function_specification:
            function_keyword:
                token : current
                after : '+1'
            close_parenthesis:
                token : '-1'
                after : current

the indentation behaves much much better. I don't fully know what you are aiming for with your config, but if you are able to use the default config, I believe that you won't experience this problem. Otherwise, I suggest that you play around with your config more to see whether there's a way that you can use +1 rather than +2 for after the function keyword. I still have gaps in my knowledge on the operation of the indentation rules, but I can try to help if needed.