[HELP]: How to run only the wanted rules ?

[wimille]

Hi everyone

It is a short time that i used the vsg tool in my developpement flow. It seems to be a great help, however i'have a few question. May be it is not the best place to ask them, if it's so tell the wright place.

My question is very simple:
I want to set my own configuration rules based of course of all rules available. But i want to run only the rules i defined.
I've wrote a small yaml file to configure 10 rules (just to start and understand the tool). But when i run the tool on a single VHD file with command:
vsg -c my_own.yaml -f bob.vhd

It runs but the output says that about 170 rules has been checked...i expected only the 10 i configured. Why is that ?

Thanks for your help.

[JHertz5]

Hi @wimille

The tool comes with a default rule configuration set up so that it can be used without any user configuration if you just want some formatting and don't really care about the details. You can see the default config by running

$ vsg --output_configuration default_config.json

It's very long, but it gives you the full details of how every rule is configured by default. To take advantage of these defaults, many users (including myself) will let the default settings cover the majority of the rules and will only modify the settings on particular things that we care about doing a particular way. Hopefully that answers your question.

If you want to disable all of the rules by default and only enable the rules that you care about, you can easily do so. As mentioned in the documentation, you can specify rule settings at different levels of scope. As the scope reduces, the priority increases. For example, a global setting for all rules has lower priority than a setting for a single specific rule.

As a result, we can globally disable all rules, and then manually enable only the rules that we want to activate.
Take the following file for example, test.vhd:

architecture rtl of test is

  SIGNAL my_sig   : boolean;


begin

end architecture rtl;

When I run the default config, I get:

$ vsg -f test.vhd -a
================================================================================
File:  test.vhd
================================================================================
Phase 7 of 7... Reporting
Total Rules Checked: 906
Total Violations:    3
  Error   :     3
  Warning :     0
-------------------+------------+------------+--------------------------------------
  Rule             |  severity  |  line(s)   | Solution
-------------------+------------+------------+--------------------------------------
  architecture_026 | Error      |          4 | Move : -2 columns
  signal_002       | Error      |          4 | Change "SIGNAL" to "signal"
  whitespace_200   | Error      |          5 | Remove 1 blank line(s) below
-------------------+------------+------------+--------------------------------------
NOTE: Refer to online documentation at https://vhdl-style-guide.readthedocs.io/en/latest/index.html for more information.

Note that 906 rules were checked and 3 violations were found, each on a different rule.

Now I introduce my config file:

rule:
  # Disable all rules.
  global:
    disable: true
  # Enable just this rule.
  signal_002:
    disable: false

and try again

$ vsg -f test.vhd -c test.yml -a
================================================================================
File:  test.vhd
================================================================================
Phase 7 of 7... Reporting
Total Rules Checked: 1
Total Violations:    1
  Error   :     1
  Warning :     0
-------------+------------+------------+--------------------------------------
  Rule       |  severity  |  line(s)   | Solution
-------------+------------+------------+--------------------------------------
  signal_002 | Error      |          4 | Change "SIGNAL" to "signal"
-------------+------------+------------+--------------------------------------
NOTE: Refer to online documentation at https://vhdl-style-guide.readthedocs.io/en/latest/index.html for more information.

Note that this time, only 1 rule was checked, and only 1 violation was reported despite the VHDL code being the same.

I hope that helps.

[wimille]

Thank you, your answer is very clear and very detailed.
And the last fully answered to my question.