Pass new commit to deploy action when sync commits

Without this, the deploy action will run with the same commit ID that started the sync action.
That results in deploying the site without the sync'd changes.
This attempts to avoid deploying when there is no new commit, and it passes the new commit to the deploy action when there is one.

.github/workflows/deploy.yml

@@ -5,6 +5,10 @@ on:
     branches:
       - main
   workflow_call:
+    inputs:
+      new-commit:
+        required: false
+        type: string
     # Review gh actions docs if you want to further define triggers, paths, etc
     # https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#on
 
@@ -14,6 +18,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+        if: "${{ inputs.new-commit == '' }}"
+      - uses: actions/checkout@v3
+        if: "${{ inputs.new-commit != '' }}"
+        with:
+          # deploy a specific commit
+          ref: ${{ inputs.new-commit }}
       - uses: actions/setup-node@v3
         with:
           node-version: 18

.github/workflows/sync-from-reddit.yml

@@ -10,6 +10,8 @@ jobs:
   sync-from-reddit:
     name: Sync from Reddit
     runs-on: ubuntu-22.04
+    outputs:
+      new-commit: ${{ steps.push.outputs.commit }}
     permissions:
       contents: write
     steps:
@@ -24,13 +26,19 @@ jobs:
         run: ./download-wiki.sh
 
       - name: Push changes (if any)
-        run: git push
+        id: push
+        run: |
+          git push
+          [ "$GITHUB_SHA" != "$(git rev-parse HEAD)"] && echo "commit=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
 
   # Pushes from GitHub Actions do not trigger further actions; manually call deploy
   deploy:
     name: Deploy site
     needs: sync-from-reddit
+    if: "${{ needs.sync-from-reddit.outputs.new-commit != '' }}"
     permissions:
       pages: write
       id-token: write
     uses: ./.github/workflows/deploy.yml
+    with:
+      new-commit: ${{ needs.sync-from-reddit.outputs.new-commit }}