fix: remove sed postprocessing from the terraform_docs_replace hook to fix compatibility with terraform-docs 0.11.0+

[choppedpork]

Since updating to terraform-docs 0.11.0+ (also affects 0.11.1 and 0.11.2) all my README.md's are now missing the last line!

After a little bit of digging I've noticed that, since version 0.11.0, terraform-docs no longer adds an extra empty newline at the end. This PR amends the sed pattern to produce the same output in <0.11.0 as in 0.11.0+:

0.10.0:

$ terraform-docs --sort-by-required md ./ | gsed -e '$ d' -e 'N;/^\n$/D;P;D' | tail -n 3
|------|-------------|
| ids | List of IDs of the created instances |
| private\_ips | The private IP addresses assigned to the instances |

$ terraform-docs --sort-by-required md ./ | gsed -e '${/^$/d;}' -e 'N;/^\n$/D;P;D' | tail -n 3
|------|-------------|
| ids | List of IDs of the created instances |
| private\_ips | The private IP addresses assigned to the instances |

0.11.0:

$ terraform-docs --sort-by-required md ./ | gsed -e '$ d' -e 'N;/^\n$/D;P;D' | tail -n 3
| Name | Description |
|------|-------------|
| ids | List of IDs of the created instances |

$ terraform-docs --sort-by-required md ./ | gsed -e '${/^$/d;}' -e 'N;/^\n$/D;P;D' | tail -n 3
|------|-------------|
| ids | List of IDs of the created instances |
| private\_ips | The private IP addresses assigned to the instances |

[antonbabenko]

I don't think we should modify the behavior and response of the tools we use in this project (eg, terraform-docs). It is going to be a moving target if we apply this PR and then terraform-docs updates.

[choppedpork]

I'm not sure I follow @antonbabenko - at the moment (without this PR) the behaviour between pre-0.11 and later is different as well as incorrect. The sed pattern has been here since the hook was added in 2018. There's no documentation around why it was added but my assumption is that it was trying to remove the last line (which until 0.11.0 was an extra empty line as well as a trailing newline). Since 0.11.0 an empty line is no longer being added and so the automatically generated documentation is incomplete. My suggested change preserves the old behaviour for older versions while making sure that the resulting README is not missing a line (in the example I gave above - and every terraform module repository I'm currently working on at work - it's missing the last output).

I do agree with you that the underlying tool output should not be modified. As a matter of fact I've created a pipeline to verify the pre-commit hooks have been applied by committers in my company and it took me a while to find why the output generated using terraform-docs was different to the output of the pre-commit hook. The reason turned out to be the sed expressions found in this hook...

I would be happy to re-raise a PR to remove the sed command altogether if you think that would be a better solution, with this fix I have decided to err on the side of caution and preserve the existing behaviour for versions pre-0.11 rather than changing it.

edit: formatting

[antonbabenko]

I apologize for misunderstanding the root of the PR and closing it so fast (sometimes I do this very fast) :)

I think it will be better if we just remove this sed altogether. Please update the code in this PR.

[choppedpork]

Thanks!

PR updated, tested and rebased. I've amended the PR title as well as added a tentative changelog entry in order for the extra newline when using pre-0.11.0 versions to not surprise anyone.

Following the changed approach this will now also supersede #31 and resolve #28.

edit: cosmetic hook changes sponsored by the addition of autopep8 to my editor.

[antonbabenko]

Thanks, @choppedpork !

v1.47.0 has been just released.

PS: Currently we autogenerate CHANGELOG from the PR messages.