- Enhance publish workflow: add validation for GitHub Release and tag checks

Co-authored-by: Copilot <copilot@github.com>

Author: EshtiakAlam

.github/workflows/publish.yaml

@@ -21,19 +21,42 @@ jobs:
           persist-credentials: false
 
       - name: Validate tag format
+        env:
+          TAG: ${{ github.ref_name }}
         run: |
-          TAG="${{ github.ref_name }}"
           VERSION="${TAG#v}"
           if ! [[ $VERSION =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
             echo "Error: Invalid version format '$VERSION'. Expected format: x.y.z"
             exit 1
           fi
           echo "Releasing version: $VERSION (from tag: $TAG)"
 
+      - name: Verify GitHub Release exists
+        env:
+          GH_TOKEN: ${{ github.token }}
+          TAG: ${{ github.ref_name }}
+        run: |
+          if ! gh release view "$TAG" --repo "$GITHUB_REPOSITORY" > /dev/null 2>&1; then
+            echo "Error: No GitHub Release found for tag '$TAG'."
+            echo "Create a release via GitHub UI instead of pushing tags manually."
+            exit 1
+          fi
+
+      - name: Verify tag is on master
+        env:
+          DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+        run: |
+          git fetch origin "$DEFAULT_BRANCH" --quiet
+          if ! git merge-base --is-ancestor "$GITHUB_SHA" "origin/$DEFAULT_BRANCH"; then
+            echo "Error: Tag commit $GITHUB_SHA is not reachable from origin/$DEFAULT_BRANCH."
+            echo "Only tags on the $DEFAULT_BRANCH branch can be published."
+            exit 1
+          fi
+
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: '3.x'
+          python-version: "3.x"
 
       - name: Install build dependencies
         run: pip install build twine setuptools-scm

README.md

@@ -1,5 +1,10 @@
-# optimizely-platform [![Build Status](https://travis-ci.org/optimizely/optimizely-platform.svg?branch=master)](https://travis-ci.org/optimizely/optimizely-platform)
+# optimizely-platform
 
 A Python package providing modules needed to build add-ons that run natively in the Optimizely platform.
 
-TODO(jon): Add link to documentation once it's up.
+## Releasing
+
+1. Merge your changes to `master`.
+2. [Create a GitHub Release](../../releases/new) with a tag in the format `vX.Y.Z` (e.g. `v1.2.3`).
+
+The `publish.yaml` workflow builds and publishes to Google Artifact Registry. It will reject tags that aren't strict semver, lack a GitHub Release, or aren't on `master`.