Use `hcl` instead of `diff` after triple backtick

[nitrocode]

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• [x] I'd be willing to implement this feature (contributing guide)

Describe the user story

I'd like to see the same colored output in atlantis' comment as I would locally in my command line

Describe the solution you'd like

Let's use hcl instead of diff after the triple backtick

https://github.com/runatlantis/atlantis/blob/b409cb8470c137b6a321d0642b42fbb96f60df56/server/events/vcs/azuredevops_client.go#L102

https://github.com/runatlantis/atlantis/blob/b409cb8470c137b6a321d0642b42fbb96f60df56/server/events/vcs/github_client.go#L186-L192

Currently we see this using diff

If we use hcl the github comment syntax highlighting would match what we see locally

Describe the drawbacks of your solution

I do not know if azure devops vcs supports the hcl coloring syntax. I know the github vcs does.

Describe alternatives you've considered

• Implement the above and add a flag to override the the text following the triple backtick
• or live with the current implementation

related

• https://github.com/runatlantis/atlantis/issues/1899
• https://github.com/runatlantis/atlantis/pull/2647

[pauloconnor]

I think the reason why diff is used over hcl is due to GitHub handling diff correctly when +. - etc are the first characters of the strings (I kinda broke this working properly https://github.com/runatlantis/atlantis/issues/2425)

This is what you'd see if it was working properly

HCL

  # module.redacted.aws_route53_record.redacted_record will be updated in-place
~ resource "aws_route53_record" "redacted_record" {
        fqdn    = "redacted.redacted.redacted.io"
        id      = "redacted_redacted.redacted.redacted.io_A"
        name    = "redacted.redacted.redacted.io"
      ~ records = [
            "foo",
          - "redacted",
        ] -> (known after apply)
        ttl     = 300
        type    = "A"
        zone_id = "redacted"
    }

Diff

  # module.redacted.aws_route53_record.redacted_record will be updated in-place
! resource "aws_route53_record" "redacted_record" {
        fqdn    = "redacted.redacted.redacted.io"
        id      = "redacted_redacted.redacted.redacted.io_A"
        name    = "redacted.redacted.redacted.io"
!       records = [
            "foo",
-           "redacted",
        ] -> (known after apply)
        ttl     = 300
        type    = "A"
        zone_id = "redacted"
    }

[nitrocode]

@pauloconnor hmmm I'm not sure I follow. I would much prefer the hcl syntax than the diff syntax. Are you saying that the hcl syntax doesn't make the deletion as obvious as the diff syntax?

I suppose this is where the custom templating comes in in the next version.

To me, it doesn't make sense why we would use a different syntax than the native hcl. The diff syntax, imho, should be an option and hcl should be preferred.

[pauloconnor]

@nitrocode I think it boils down to diff making changes more obvious than hcl does. Personal preference as to which you prefer.

[nitrocode]

This is a duplicate of https://github.com/runatlantis/atlantis/issues/1339 apparently.

Perhaps the best way to implement this then is with a feature flag such as --markdown-plan-color and it can default to diff and set to hcl for people that want to change it. It would also meaning restoring the plan output so its not modified for the diff type.

[rpdelaney]

#1339 was closed with a feature that allows the user to supply their own templates. I'm taking that as a signal that they don't want to do the work to support variants of the templates they already maintain. Edit: ...which is completely fair, to be clear.