Add stable branch syncing and webhook for readthedocs build triggering

.github/workflows/sync-stable-branch.yml

@@ -0,0 +1,83 @@
+name: Sync Stable Branch with Slang Release
+
+on:
+  schedule:
+    # Run at 3:00 AM UTC every day
+    - cron: '0 3 * * *'
+  workflow_dispatch:  # Allow manual trigger
+
+jobs:
+  sync-stable-branch:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: Checkout main branch
+        uses: actions/checkout@v4
+        with:
+          ref: main # Explicitly checkout main
+          # Fetch all history for all branches and tags
+          fetch-depth: 0
+          # Get submodules, but don't update them yet
+          submodules: 'recursive'
+
+      - name: Set up Git
+        run: |
+          git config --global user.name 'Read the Docs Bot'
+          git config --global user.email 'rtd-bot@shader-slang.com'
+
+      - name: Get latest slang release tag
+        id: slang_latest_tag
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Provide token explicitly for gh
+        run: |
+          LATEST_TAG=$(gh release view --repo shader-slang/slang --json tagName --jq .tagName)
+          if [ -z "$LATEST_TAG" ]; then
+            echo "Failed to fetch latest slang release tag using gh"
+            exit 1
+          fi
+          echo "tag=$LATEST_TAG" >> $GITHUB_OUTPUT
+          echo "Fetched latest slang tag: $LATEST_TAG"
+
+      - name: Update slang submodule to latest release tag
+        run: |
+          pushd docs/external/slang
+          git fetch --tags origin
+          git checkout ${{ steps.slang_latest_tag.outputs.tag }}
+          popd
+          echo "Checked out tag ${{ steps.slang_latest_tag.outputs.tag }} in docs/external/slang"
+
+      - name: Check for changes
+        id: check_changes
+        run: |
+          # Only stage the slang submodule, as the others are already updated
+          git add docs/external/slang
+
+          # Check if the index differs from HEAD
+          # git diff --cached --quiet exits 0 if no diff, 1 if diff
+          if ! git diff --cached --quiet; then
+            echo "Changes detected in submodule references."
+            echo "changes=true" >> $GITHUB_OUTPUT
+          else
+            echo "No changes detected in submodule references."
+            echo "changes=false" >> $GITHUB_OUTPUT
+            # If no changes, reset the index in case unrelated changes were staged
+            git reset HEAD --quiet
+          fi
+
+      - name: Commit and push changes to stable branch
+        if: steps.check_changes.outputs.changes == 'true'
+        run: |
+          git commit -m "Sync stable to release (slang@${{ steps.slang_latest_tag.outputs.tag }})"
+          git push origin HEAD:stable --force
+          echo "Committed and force-pushed updates to stable branch."
+
+      - name: Trigger Read the Docs Build on stable branch update
+        if: steps.check_changes.outputs.changes == 'true'
+        env:
+          RTD_WEBHOOK_SECRET: ${{ secrets.RTD_WEBHOOK_SECRET }}
+        run: |
+          curl -X POST \
+               -H "Authorization: token $RTD_WEBHOOK_SECRET" \
+               https://readthedocs.org/api/v2/webhook/slang-documentation/296117/
+          echo "Triggered Read the Docs build."

.github/workflows/update-submodules.yml

@@ -22,8 +22,8 @@ jobs:
 
       - name: Set up Git
         run: |
-          git config --global user.name 'github-actions'
-          git config --global user.email 'github-actions@github.com'
+          git config --global user.name 'Read the Docs Bot'
+          git config --global user.email 'rtd-bot@shader-slang.com'
 
       - name: Get default branch
         id: default_branch
@@ -42,15 +42,31 @@ jobs:
       - name: Check if submodules changed
         id: check_changes
         run: |
-          if [[ -n "$(git status --porcelain)" ]]; then
+          git add -A
+
+          # Check if the index differs from HEAD
+          # git diff --cached --quiet exits 0 if no diff, 1 if diff
+          if ! git diff --cached --quiet; then
+            echo "Changes detected in submodule references."
             echo "changes=true" >> $GITHUB_OUTPUT
           else
+            echo "No changes detected in submodule references."
             echo "changes=false" >> $GITHUB_OUTPUT
+            # If no changes, reset the index in case unrelated changes were staged
+            git reset HEAD --quiet
           fi
 
       - name: Commit and push changes
         if: steps.check_changes.outputs.changes == 'true'
         run: |
-          git add -A
           git commit -m "Auto-update submodules"
-          git push origin ${{ steps.default_branch.outputs.name }} 
+          git push origin ${{ steps.default_branch.outputs.name }}
+
+      - name: Trigger Read the Docs Build
+        if: steps.check_changes.outputs.changes == 'true'
+        env:
+          RTD_WEBHOOK_SECRET: ${{ secrets.RTD_WEBHOOK_SECRET }}
+        run: |
+          curl -X POST \
+               -H "Authorization: token $RTD_WEBHOOK_SECRET" \
+               https://readthedocs.org/api/v2/webhook/slang-documentation/296117/