ci: caller for PostHog/.github changeset-hygiene workflow

[turnipdabeets]

Updated to use merged workflow in PostHog/.github#39

💡 Motivation and Context

Adds a tiny caller workflow for the shared changeset-hygiene reusable workflow at PostHog/.github. Catches the class of mistake that caused #491 → #507: a changeset frontmatter pointing at the wrong workspace package, plus a few related failure modes:

• changeset declares a package the PR didn't modify
• PR modifies a package no changeset declares (the chore: attach release info to proguard mapping upload #491 case)
• changeset declares a name not in the workspace (typo)
• PR modifies workspace package code but adds no changeset at all

This PR carries no logic of its own — the workflow + script live in PostHog/.github so all SDKs share them. This file just delegates.

What it does

• Triggers on pull_request against main.
• Delegates to the reusable workflow via uses: PostHog/.github/.github/workflows/changeset-hygiene.yml@main.
• Posts a single sticky comment under <!-- changeset-hygiene --> when there's a coverage issue. Auto-deletes when fixed. Never blocks merging.

Caller is 18 lines

The whole change is one file: .github/workflows/changeset-hygiene.yml. The actual workflow + script are at PostHog/.github/.github/workflows/changeset-hygiene.yml and PostHog/.github/.github/scripts/check-changeset-coverage.mjs.

Test plan

Verified end-to-end on the parallel test PR #510, which uses the same caller plus deliberate simulation files (source change in posthog-android-gradle-plugin/ paired with a changeset declaring posthog-android). The workflow correctly posted the expected mismatch comment.

This PR's own CI run (no workspace package changes, no changeset) correctly stays silent — the workflow only comments when there's an issue.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran pnpm changeset to generate a changeset file
• Added the "release" label to the PR to indicate we're publishing new versions for the affected packages

(CI-only change — no workspace package code is touched, so no changeset is needed.)

[marandaneto]

does it also cover the use case where maybe we have modinified packages but no changeset at all? i think this would be great as well

also take a look at posthog-js/.github/workflows/check-posthog-major-version.yml (Comment about missing changeset) since theres something in there as well
we probably want to cover any other use case where we failed before and then port across all sdks
if possible, this would live in https://github.com/PostHog/.github/tree/main/.github/workflows and then we just reuse across repos

[turnipdabeets]

does it also cover the use case where maybe we have modinified packages but no changeset at all? i think this would be great as well

also take a look at posthog-js/.github/workflows/check-posthog-major-version.yml (Comment about missing changeset) since theres something in there as well we probably want to cover any other use case where we failed before and then port across all sdks if possible, this would live in PostHog/.github@main/.github/workflows and then we just reuse across repos

@marandaneto I moved this to PostHog/.github#39. Considered joining with check-posthog-major-version.yml but they seem to be a bit different and js want to block on major versions. I don't think we want that in other repos so that can stay in js repo and we can share this across other repos.

[marandaneto]

Nice!!!