changeset-pr-npmdiff-comment.yml

name: Changeset PR npm diff links

on:
  pull_request:
    types: [opened, reopened, synchronize]

concurrency:
  group: changeset-pr-npmdiff-${{ github.event.pull_request.number }}
  cancel-in-progress: true

permissions:
  contents: read
  pull-requests: write

jobs:
  comment:
    if: >
      github.event.pull_request.head.repo.full_name == github.repository &&
      startsWith(github.event.pull_request.head.ref, 'changeset-release/') &&
      startsWith(github.event.pull_request.title, 'Version Packages')
    runs-on: ubuntu-latest
    steps:
      - name: Post or update npmdiff comment
        uses: actions/github-script@v9
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const COMMENT_MARKER = '<!-- changeset-pr-npmdiff-links -->'
            const PACKAGE_JSON_PATTERN =
              /^(?:plugins\/(?:@sanity\/[^/]+|sanity-plugin-[^/]+)|packages\/@sanity\/plugin-kit)\/package\.json$/

            const {owner, repo} = context.repo
            const pr = context.payload.pull_request

            const changedFiles = await github.paginate(github.rest.pulls.listFiles, {
              owner,
              repo,
              pull_number: pr.number,
              per_page: 100,
            })

            async function getPackageJson(path, ref) {
              const {data} = await github.rest.repos.getContent({
                owner,
                repo,
                path,
                ref,
              })

              if (!('content' in data)) return null

              return JSON.parse(Buffer.from(data.content, data.encoding).toString('utf8'))
            }

            const packageDiffs = []

            for (const file of changedFiles) {
              if (!PACKAGE_JSON_PATTERN.test(file.filename) || file.status === 'removed') {
                continue
              }

              try {
                const [basePkg, headPkg] = await Promise.all([
                  getPackageJson(file.filename, pr.base.sha),
                  getPackageJson(file.filename, pr.head.sha),
                ])

                if (!basePkg || !headPkg) continue
                if (headPkg.private === true) continue
                if (!basePkg.version || !headPkg.version) continue
                if (basePkg.version === headPkg.version) continue
                if (!headPkg.name) continue

                packageDiffs.push({
                  name: headPkg.name,
                  fromVersion: basePkg.version,
                  toVersion: headPkg.version,
                  url: `https://npmdiff.dev/${encodeURIComponent(headPkg.name)}/${encodeURIComponent(basePkg.version)}/${encodeURIComponent(headPkg.version)}`,
                })
              } catch (error) {
                console.warn(`Failed to process ${file.filename}:`, error.message)
              }
            }

            packageDiffs.sort((a, b) => a.name.localeCompare(b.name))

            const body = packageDiffs.length
              ? [
                  '## Package diff links for this Changesets PR',
                  '',
                  'These links start working after this PR is merged and the release is published to npm, and can be used to verify that published packages did not include unexpected changes:',
                  '',
                  ...packageDiffs.map(
                    (pkg) =>
                      `- \`${pkg.name}\` (${pkg.fromVersion} → ${pkg.toVersion}): [npmdiff.dev](${pkg.url})`,
                  ),
                  '',
                  COMMENT_MARKER,
                ].join('\n')
              : [
                  '## Package diff links for this Changesets PR',
                  '',
                  'No published package version changes were detected in this PR.',
                  '',
                  COMMENT_MARKER,
                ].join('\n')

            const comments = await github.paginate(github.rest.issues.listComments, {
              owner,
              repo,
              issue_number: pr.number,
              per_page: 100,
            })

            const existingComment = comments.find((comment) => comment.body.includes(COMMENT_MARKER))

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner,
                repo,
                comment_id: existingComment.id,
                body,
              })
            } else {
              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number: pr.number,
                body,
              })
            }