Check if any news fragments have invalid filenames

[MetRonnie]

Description

Closes #619
Fixes #426

towncrier check will now fail if any news fragments have invalid filenames.

Added a new configuration option called build_ignore_filenames that allows you to specify a list of filenames that should be ignored. If this is set, towncrier build will also fail if any filenames are invalid, except for those in the list.

Added a --strict option to towncrier build to enable this behaviour for when build_ignore_filenames has not been configured.

Checklist

• Make sure changes are covered by existing or new tests.
• For at least one Python version, make sure local test run is green.
• Create a file in src/towncrier/newsfragments/. Describe your
  change and include important information. Your change will be included in the public release notes.
• Make sure all GitHub Actions checks are green (they are automatically checking all of the above).
• Ensure docs/tutorial.rst is still up-to-date.
• If you add new CLI arguments (or change the meaning of existing ones), make sure docs/cli.rst reflects those changes.
• If you add new configuration options (or change the meaning of existing ones), make sure docs/configuration.rst reflects those changes. (Not applicable)

[adiroiban]

Thanks for working on this.

This needs documentation and tests to be merged.

---

While reviewing this, my question is.

Why do we ever want to allow towncrier build or towncrier check to succeed if there are in invalid fragments.

I understand that you might want to have other files inside the newsfragment folder (for example the template and a README) but other than that, I think towncrier should fail

Cheers

[MetRonnie]

I think all feedback has been addressed now. Let me know if there is anything else.

Maybe a warning if towncrier build encounters invalid filenames but build_ignore_filenames has not been configured? Do you envisage deprecating the --strict option and making the fail behaviour the default in a future version of Towncrier?

[adiroiban]

Many thanks for the changes.

They look good.

As a general rule, I think that is best to start any new functionality by writing the documentation.

In this way, we can agree on how the feature should behave, before writing more code.

---

I think that we can have this implemented without the --strict option.

In terms for testing I am expecting 3 main test scenarios:

• build_ignore_filenames not set
• build_ignore_filenames is set to empty list
• build_ignore_filenames is set with some filenames

Thanks again for working on this!

[adiroiban]

I forgot to leave this feedback

Maybe a warning if towncrier build encounters invalid filenames but build_ignore_filenames has not been configured?

That would be nice. We can also have this in a separate PR.
This should not be a blocker.

---

Do you envisage deprecating the --strict option and making the fail behaviour the default in a future version of Towncrier?

I hope that we don't have to add the --strict option... so that we don't have to deprecate it.

It would be nice to have a warinig raised when build_ignore_filenames is not configured and make a release that raised the warning.

In a followup release, we can then change the default value of build_ignore_filenames so thta it will alwasy do a strict check by default... while still allowing users to configure it with build_ignore_filenames = None`

[adiroiban]

I have updated the PR description to note that it will also fix #426 ... the #619 might be a duplicate

[adiroiban]

Many thanks for the changes.

They look good.

I have to still review the automated tests... but the other part looks good.

[adiroiban]

We can keep it. No problem.

The critical part is to make sure that we have automated tests that will fail is anyone would move this code :)

[adiroiban]

Not sure how this will ended up in the rendered version.

We should have 2 fragments here.
One for towncrier check

and another one for the ignore configuration option.

---

But maybe the towncrier check part can be left out.

If build fails, it should be expect for check to also fail.

[MetRonnie]

I feel like the addition of the config option and the new fail behaviour are intertwined, so I think it makes sense to have them in the same fragment. At least I think the change in behaviour of towncrier check should be clearly signposted.

I could rewrite this to be clearer, how about:

towncrier check will now fail if any news fragments have invalid filenames. You can specify filenames to ignore in the news fragments directory with the new ignore configuration option. towncrier build will not fail on invalid filenames unless ignore is set (can be an empty list).

[adiroiban]

As you think it's best

we can leave it as it is. no problem.

[adiroiban]

Looks good. Many thanks for the changes.

[adiroiban]

Thanks. I didn't had time to check the test coverage... but if say that you have checked it, we can have this merged :)

no problem

[adiroiban]

As you think it's best

we can leave it as it is. no problem.

[adiroiban]

Thanks for the update. I have enabled auto-merge.

I hope this will be merged soon.

I plan to do a new release soon... I hope #627 will also be merge soon and then we can have a release.