chore(ci): migrate release pipeline from release-please App to GitHub Actions

Remove the release-please GitHub App config files and add an Actions-based
release pipeline with candidate branch strategy. This includes workflows for
cutting releases, running release-please, finalizing releases, publishing to
PyPI, and cherry-picking fixes to release candidates.

Co-authored-by: Wei Sun (Jack) <weisun@google.com>
PiperOrigin-RevId: 868825704

.github/.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "1.24.1"
+}

.github/release-please-config.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "packages": {
+    ".": {
+      "release-type": "python",
+      "package-name": "google-adk",
+      "include-component-in-tag": false,
+      "skip-github-release": true,
+      "changelog-path": "CHANGELOG.md",
+      "changelog-sections": [
+        {"type": "feat", "section": "Features"},
+        {"type": "fix", "section": "Bug Fixes"},
+        {"type": "perf", "section": "Performance Improvements"},
+        {"type": "refactor", "section": "Code Refactoring"},
+        {"type": "docs", "section": "Documentation"},
+        {"type": "test", "section": "Tests", "hidden": true},
+        {"type": "build", "section": "Build System", "hidden": true},
+        {"type": "ci", "section": "CI/CD", "hidden": true},
+        {"type": "style", "section": "Styles", "hidden": true},
+        {"type": "chore", "section": "Miscellaneous Chores", "hidden": true}
+      ]
+    }
+  }
+}

.github/release-please.yml

@@ -1,5 +0,0 @@
-releaseType: python
-handleGHRelease: true
-bumpMinorPreMajor: false
-extraFiles:
-  - src/google/adk/version.py

.github/release-trigger.yml

@@ -1 +0,0 @@
-enabled: true

.github/workflows/release-cherry-pick.yml

@@ -0,0 +1,46 @@
+# Cherry-picks a commit from main to the release/candidate branch.
+# Use this to include bug fixes in an in-progress release.
+name: "Release: Cherry-pick"
+
+on:
+  workflow_dispatch:
+    inputs:
+      commit_sha:
+        description: 'Commit SHA to cherry-pick'
+        required: true
+        type: string
+
+permissions:
+  contents: write
+  actions: write
+
+jobs:
+  cherry-pick:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: release/candidate
+          fetch-depth: 0
+
+      - name: Configure git
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Cherry-pick commit
+        run: |
+          echo "Cherry-picking ${{ inputs.commit_sha }} to release/candidate"
+          git cherry-pick ${{ inputs.commit_sha }}
+
+      - name: Push changes
+        run: |
+          git push origin release/candidate
+          echo "Successfully cherry-picked commit to release/candidate"
+
+      - name: Trigger Release Please
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh workflow run release-please.yml --repo ${{ github.repository }}
+          echo "Triggered Release Please workflow"

.github/workflows/release-cut.yml

@@ -0,0 +1,46 @@
+# Starts the release process by creating a release/candidate branch.
+# Triggers release-please to generate a changelog PR.
+name: "Release: Cut"
+
+on:
+  workflow_dispatch:
+    inputs:
+      commit_sha:
+        description: 'Commit SHA to cut from (leave empty for latest main)'
+        required: false
+        type: string
+
+permissions:
+  contents: write
+  actions: write
+
+jobs:
+  cut-release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.commit_sha || 'main' }}
+
+      - name: Check for existing release/candidate branch
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          if git ls-remote --exit-code --heads origin release/candidate &>/dev/null; then
+            echo "Error: release/candidate branch already exists"
+            echo "Please finalize or delete the existing release candidate before starting a new one"
+            exit 1
+          fi
+
+      - name: Create and push release/candidate branch
+        run: |
+          git checkout -b release/candidate
+          git push origin release/candidate
+          echo "Created branch: release/candidate"
+
+      - name: Trigger Release Please
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh workflow run release-please.yml --repo ${{ github.repository }}
+          echo "Triggered Release Please workflow"

.github/workflows/release-finalize.yml

@@ -0,0 +1,66 @@
+# Triggers when release-please PR is merged to release/candidate.
+# Creates the final release/v{version} branch and deletes the candidate branch.
+name: "Release: Finalize"
+
+on:
+  pull_request:
+    types: [closed]
+    branches:
+      - release/candidate
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  finalize:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check for release-please PR
+        id: check
+        env:
+          LABELS: ${{ toJson(github.event.pull_request.labels.*.name) }}
+        run: |
+          if echo "$LABELS" | grep -q "autorelease: pending"; then
+            echo "is_release_pr=true" >> $GITHUB_OUTPUT
+          else
+            echo "Not a release-please PR, skipping"
+            echo "is_release_pr=false" >> $GITHUB_OUTPUT
+          fi
+
+      - uses: actions/checkout@v4
+        if: steps.check.outputs.is_release_pr == 'true'
+        with:
+          ref: release/candidate
+
+      - name: Extract version from manifest
+        if: steps.check.outputs.is_release_pr == 'true'
+        id: version
+        run: |
+          VERSION=$(jq -r '.["."]' .github/.release-please-manifest.json)
+          echo "version=$VERSION" >> $GITHUB_OUTPUT
+          echo "Extracted version: $VERSION"
+
+      - name: Create release branch
+        if: steps.check.outputs.is_release_pr == 'true'
+        run: |
+          git checkout -b "release/v${{ steps.version.outputs.version }}"
+          git push origin "release/v${{ steps.version.outputs.version }}"
+          echo "Created branch: release/v${{ steps.version.outputs.version }}"
+
+      - name: Delete release/candidate branch
+        if: steps.check.outputs.is_release_pr == 'true'
+        run: |
+          git push origin --delete release/candidate
+          echo "Deleted branch: release/candidate"
+
+      - name: Update PR label to tagged
+        if: steps.check.outputs.is_release_pr == 'true'
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh pr edit ${{ github.event.pull_request.number }} \
+            --remove-label "autorelease: pending" \
+            --add-label "autorelease: tagged"
+          echo "Updated PR label to autorelease: tagged"

.github/workflows/release-please.yml

@@ -0,0 +1,30 @@
+# Runs release-please to create/update a PR with version bump and changelog.
+# Triggered by pushes to release/candidate or manually.
+name: "Release: Please"
+
+on:
+  push:
+    branches:
+      - release/candidate
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  release-please:
+    # Skip if this is a release-please PR merge (handled by Release: Finalize)
+    if: "!startsWith(github.event.head_commit.message, 'chore(release')"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: release/candidate
+
+      - uses: googleapis/release-please-action@v4
+        with:
+          token: ${{ secrets.RELEASE_PAT }}
+          config-file: .github/release-please-config.json
+          manifest-file: .github/.release-please-manifest.json
+          target-branch: release/candidate

.github/workflows/release-publish.yml

@@ -0,0 +1,59 @@
+# Builds and publishes the package to PyPI from a release branch.
+# Creates a merge-back PR to sync release changes to main.
+name: "Release: Publish to PyPi"
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Validate branch
+        run: |
+          if [[ ! "${{ github.ref_name }}" =~ ^release/v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            echo "Error: Must run from a release/v* branch (e.g., release/v0.3.0)"
+            exit 1
+          fi
+
+      - name: Extract version
+        id: version
+        run: |
+          VERSION="${{ github.ref_name }}"
+          VERSION="${VERSION#release/v}"
+          echo "version=$VERSION" >> $GITHUB_OUTPUT
+          echo "Publishing version: $VERSION"
+
+      - uses: actions/checkout@v4
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v4
+        with:
+          version: "latest"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Build package
+        run: uv build
+
+      - name: Publish to PyPI
+        env:
+          UV_PUBLISH_TOKEN: ${{ secrets.PYPI_TOKEN }}
+        run: uv publish
+
+      - name: Create merge-back PR
+        env:
+          GH_TOKEN: ${{ secrets.RELEASE_PAT }}
+        run: |
+          gh pr create \
+            --base main \
+            --head "${{ github.ref_name }}" \
+            --title "chore: merge release v${{ steps.version.outputs.version }} to main" \
+            --body "Syncs version bump and CHANGELOG from release v${{ steps.version.outputs.version }} to main."