feat: filter footers

[jan-ferdinand]

Description

Enable footer-based commit parsing. The idea is to add functionality like

commit_parsers = [
  { footer = "Hello: world", skip = true },
]

I would appreciate some guidance – is this useful, desired, worth it, …?

Motivation and Context

In order to keep my changelogs concise, I would like to ignore certain commits. I would like to specify whether a commit should be ignored in the commit message. A somewhat elegant way to achieve this (I think) would be to include a footer like changelog: ignore.
(If you have a better way to approach this, I'm happy to learn of it.)

How Has This Been Tested?

Append existing tests that create sample changelogs.

The test changelog_generator_split_commits is failing. It appears that a footer's value (but not the key) makes its way into the changelog. This might be because the footer's key is interpreted as a conventional commit type. I would appreciate some guidance here.

Possible Limitations

The conventional commits' specification and the reference implementation of its parser are currently out of sync. This might mean that the commit parser {footer = "Hello: world"} does not work (even though it should), whereas the commit parser {footer = "Hello:world"} does work (even though omitting the space goes against the specification).

Some relevant issues concerning footer parsing are:

• Grammar does not enforce whitespace after : token in footers conventional-commits/parser#47
• Grammar cannot read git trailers conventional-commits/parser#41
• fix: footer seperator : requires space crate-ci/git-conventional#54

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (no code change)
• Refactor (refactoring production code)
• Other

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.
• I have formatted the code with rustfmt.
• I checked the lints with clippy.
• I have added tests to cover my changes.
• All new and existing tests passed.

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[orhun]

Thanks for the PR!

I would appreciate some guidance – is this useful, desired, worth it, …?
A somewhat elegant way to achieve this (I think) would be to include a footer like changelog: ignore.

I'm wondering if the same can be achieved with body which git-cliff already supports filtering.

I'm also wondering if this is useful for #382. But I'm guessing "This commit reverts" is not a part of the footer.

The test changelog_generator_split_commits is failing. It appears that a footer's value (but not the key) makes its way into the changelog. This might be because the footer's key is interpreted as a conventional commit type. I would appreciate some guidance here.

That is the expected behavior so I recommend you to either add a new CommitParser to changelog_generator_split_commits to skip that commit or update the expected result accordingly to include that commit in the changelog.

Overall, I think this might be useful. Can you update the documentation about the existence of footer filter and also add a test fixture to verify it's behavior?

[orhun]

ping @jan-ferdinand 🙂

[jan-ferdinand]

Other things have come up and are more pressing right now; I'll come back to this. Apologies if that creates inconveniencies.

[orhun]

No worries!