Check commit messages

Commit messages are often converted into changelogs which are often then committed back into repositories.

If a repository has enabled incremental checking, then it wouldn't be terribly hard to check commit messages on PRs (or non-default branches).

This would be optional, and I don't expect it to be on by default (although I may enable it in spell-check-this's workflow).

It's somewhat similar to Feature: Check filenames and paths.

Status

• 🐛 Flaky in v0.0.21.
• 💅 Improved for v0.0.26.

See Future work for thoughts on how to improve the implementation.

If you choose to use this feature today, you should either use only_check_changed_files or include text in advice.md suggesting that commit message / PR items be added to allow.txt instead of expect.txt.

Implemented modes

• latest commit
• commits since last push / pr base
• PR description
• PR summary

ℹ️ Note: While PR description and PR summary aren't technically commit messages, there are a number of commit strategies (especially Squash) that will end up integrating them into a future commit, and thus it makes sense to offer to check them as well.

Improve commit retrieval performance

Implemented in v0.0.23 Previously check-spelling asked actions/checkout to retrieve the full commit history.

That's pretty inefficient, because for this feature, it doesn't need anything beyond the commit messages.

Switched to clone mode --filter=tree:0 which should allow for a much faster retrieval (on large repositories). It's described in Get up to speed with partial clone and shallow clone.

Improve reporting

Tentatively for v0.0.26.

While unrecognized words in commit messages and pull requests are typos, treating exactly the same as unrecognized words in code doesn't quite work. Since expect.txt is processed against what is included in the codebase, items that would transiently be seen in commit messages / pull requests really don't fit there.

As of v0.0.26, such words will:

• be listed in details by their own distinct events### (unrecognized-spelling-commit-message / unrecognized-spelling-pr-description / unrecognized-spelling-pr-title
• not be suggested as additions to expect.txt
• not be reported in the list of unrecognized words

Future Work

Split the check pass for these objects from the main pass. In order to handle them, items really need to be added to allow.txt, otherwise a commit that adds a term to expect.txt to accept a commit message will then force the next PRs to remove the newly inserted expect.txt items.

Presentation

Lazy hackish implementation

1. Create a branch w/ the selected items as files
2. push it
3. let check spelling run normally

GitHub Step Summary

Use $GITHUB_STEP_SUMMARY

• Possibly show the git commands to see the individual commit message, e.g.
  • git show [SHA]
  • curl api to get the pr description

Potential additional modes

• n commits - This is trivial to implement, but without a use case, I don't intend to implement it
• commits since a specific sha or branch - This might be necessary in order to support adding items to expect.txt, although I'm convinced it makes more sense to use allow.txt or patterns.txt.

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