release-git(announcement): add a helpful comment

Since the Git mailing list so helpfully denies us the ability to post
emails from Azure IPs, Git for Windows' announcement emails have to be
sent manually again, which is a hassle.

To make the process easier, add a PR comment with a direct link to the
artifact containing the announcement email, and while at it also prepare
an announcement to share on Bluesky.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.github/workflows/release-git.yml

@@ -109,6 +109,60 @@ jobs:
         with:
           name: bundle-artifacts
           path: bundle-artifacts
+      - name: Publish announcement mail as a stand-alone artifact
+        id: announcement
+        uses: actions/upload-artifact@v4
+        with:
+          name: announcement
+          path: bundle-artifacts/announce-*
+      - uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ secrets.GH_APP_ID }}
+          private-key: ${{ secrets.GH_APP_PRIVATE_KEY }}
+          owner: ${{ env.OWNER }}
+          repositories: |
+            ${{ env.REPO }}
+      - name: Add a comment about the announcement email to the Pull Request
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ steps.app-token.outputs.token }}
+          script: |
+            const gitSHA = ${{ toJson(steps.bundle-artifacts.outputs.git-rev) }}
+            const tagName = ${{ toJson(steps.bundle-artifacts.outputs.tag-name) }}
+            const ver = ${{ toJson(steps.bundle-artifacts.outputs.ver) }}
+            const announcementURL = ${{ toJson(steps.announcement.outputs.announcement) }}
+
+            const nth = (n) => {
+              const suffix = ((n + 89) % 100) > 2 && ['th', 'st', 'nd', 'rd'][n % 10] || 'th'
+              return `${n}${suffix}`
+            }
+
+            const releaseURL = `https://github.com/${process.env.OWNER}/${process.env.REPO}/releases/tag/${tagName}`
+            const [, baseVersion, rc ] = ver.match(/^(.*)-rc(\d+)$/) || [ver]
+            const skeet =
+              rc
+              ? `The ${nth(Number.parseInt(rc) + 1)} release candidate of Git for Windows ${baseVersion} is available, please test! ${releaseURL}`
+              : `Git for Windows ${baseVersion} is available! ${releaseURL}`
+            const blueskyLink = `https://bsky.app/intent/compose?text=${encodeURIComponent(skeet)}`
+
+            const body = `please [Share on Bluesky](${blueskyLink}) and send [the announcement email](${announcementURL}).`
+
+            const q = `repo:${process.env.OWNER}/${process.env.REPO}+is:pr+is:open+${gitSHA}`
+            const { data } = await github.rest.search.issuesAndPullRequests({ q })
+            if (data.items.length === 1) {
+              const author = data.items[0].user.login
+              const req = {
+                owner: process.env.OWNER,
+                repo: process.env.REPO,
+                issue_number: data.items[0].number,
+                body: `@${author}, ${body}`,
+              }
+
+              await github.rest.issues.createComment(req)
+            } else {
+              core.warning(`${data.items.length} PRs found for ${gitSHA}, not posting a comment, would have posted\n${body}`)
+            }
   github-release:
     needs: ['setup']
     runs-on: ubuntu-latest