chore: Add script to automate PR merging

.github/scripts/go.mod

@@ -0,0 +1,10 @@
+module github.com/googleapis/google-cloud-java/scripts
+
+go 1.24.4
+
+require (
+	github.com/google/go-github/v62 v62.0.0
+	golang.org/x/oauth2 v0.31.0
+)
+
+require github.com/google/go-querystring v1.1.0 // indirect

.github/scripts/go.sum

@@ -0,0 +1,10 @@
+github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-github/v62 v62.0.0 h1:/6mGCaRywZz9MuHyw9gD1CwsbmBX8GWsbFkwMmHdhl4=
+github.com/google/go-github/v62 v62.0.0/go.mod h1:EMxeUqGJq2xRu9DYBMwel/mr7kZrzUOfQmmpYrZn2a4=
+github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
+github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
+golang.org/x/oauth2 v0.31.0 h1:8Fq0yVZLh4j4YA47vHKFTa9Ew5XIrCP8LC6UeNZnLxo=
+golang.org/x/oauth2 v0.31.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

.github/scripts/release_manager_merge_bot.go

@@ -0,0 +1,199 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// release_manager_merge_bot is a script that automatically retries and merges a pull request.
+//
+// This script is designed to be run manually for a specific pull request. It will:
+// 1. Check the CI/CD status of the pull request.
+// 2. If the status is "failure", it will add Kokoro labels to retry the tests. It retries once.
+// 3. If the status is "success", it will squash and merge the pull request.
+// 4. If the status is "pending", it will wait and check again.
+//
+// Prerequisites:
+// - Go must be installed (https://golang.org/doc/install).
+// - A GitHub personal access token with repo scope must be set in the GITHUB_TOKEN environment variable.
+//
+// Example Usage:
+//
+// export GITHUB_TOKEN="<your GitHub token>"
+// cd .github/scripts
+// go run ./release_manager_merge_bot.go <PR URL>
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/go-github/v62/github"
+	"golang.org/x/oauth2"
+)
+
+// --- Configuration ---
+// The labels to add when a test fails.
+var labelsToAdd = []string{"kokoro:force-run", "kokoro:run"}
+
+// --- End of Configuration ---
+
+// parseURL parses a GitHub pull request URL and returns the owner, repository, and PR number.
+func parseURL(prURL string) (string, string, int, error) {
+	parsedURL, err := url.Parse(prURL)
+	if err != nil {
+		return "", "", 0, fmt.Errorf("failed to parse URL: %w", err)
+	}
+
+	pathParts := strings.Split(strings.Trim(parsedURL.Path, "/"), "/")
+	if len(pathParts) < 4 || pathParts[2] != "pull" {
+		return "", "", 0, fmt.Errorf("invalid GitHub pull request URL format")
+	}
+
+	owner := pathParts[0]
+	repo := pathParts[1]
+	prNumber, err := strconv.Atoi(pathParts[3])
+	if err != nil {
+		return "", "", 0, fmt.Errorf("failed to parse PR number: %w", err)
+	}
+
+	return owner, repo, prNumber, nil
+}
+
+// getMissingLabels checks for required labels on a PR and returns any that are missing.
+func getMissingLabels(ctx context.Context, client *github.Client, owner, repo string, prNumber int) ([]string, error) {
+	currentLabels, _, err := client.Issues.ListLabelsByIssue(ctx, owner, repo, prNumber, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get PR labels: %w", err)
+	}
+
+	labelSet := make(map[string]bool)
+	for _, label := range currentLabels {
+		labelSet[*label.Name] = true
+	}
+
+	var missingLabels []string
+	for _, requiredLabel := range labelsToAdd {
+		if !labelSet[requiredLabel] {
+			missingLabels = append(missingLabels, requiredLabel)
+		}
+	}
+	return missingLabels, nil
+}
+
+func main() {
+	log.Println("Starting the release manager merge bot.")
+
+	if len(os.Args) < 2 {
+		log.Fatal("Error: Pull request URL is required. Example: go run ./release_manager_merge_bot.go <PR URL>")
+	}
+	prURL := os.Args[1]
+
+	githubToken := os.Getenv("GITHUB_TOKEN")
+	if githubToken == "" {
+		log.Fatal("Error: GITHUB_TOKEN environment variable is not set.")
+	}
+
+	owner, repo, prNumber, err := parseURL(prURL)
+	if err != nil {
+		log.Fatalf("Error parsing URL: %v", err)
+	}
+
+	ctx := context.Background()
+	ts := oauth2.StaticTokenSource(&oauth2.Token{AccessToken: githubToken})
+	tc := oauth2.NewClient(ctx, ts)
+	client := github.NewClient(tc)
+
+	// --- Initial Label Check ---
+	retryCount := 0
+	log.Printf("Performing initial label check for PR #%d...", prNumber)
+	missingLabels, err := getMissingLabels(ctx, client, owner, repo, prNumber)
+	if err != nil {
+		log.Printf("Warning: could not perform initial label check: %v", err)
+	} else {
+		if len(missingLabels) > 0 {
+			log.Println("Required Kokoro labels are missing. Adding them now...")
+			_, _, err := client.Issues.AddLabelsToIssue(ctx, owner, repo, prNumber, missingLabels)
+			if err != nil {
+				log.Printf("Warning: failed to add labels: %v", err)
+			}
+			retryCount++
+		} else {
+			log.Println("Required Kokoro labels are already present.")
+		}
+	}
+	// --- End of Initial Label Check ---
+
+	for {
+		log.Printf("Checking status of PR #%d in %s/%s...", prNumber, owner, repo)
+
+		// Declare variables at the top of the loop to avoid 'goto jumps over declaration' errors.
+		var (
+			pr     *github.PullRequest
+			status *github.CombinedStatus
+			state  string
+			err    error
+		)
+
+		pr, _, err = client.PullRequests.Get(ctx, owner, repo, prNumber)
+		if err != nil {
+			log.Printf("An error occurred while getting PR info: %v", err)
+			goto wait
+		}
+
+		status, _, err = client.Repositories.GetCombinedStatus(ctx, owner, repo, *pr.Head.SHA, nil)
+		if err != nil {
+			log.Printf("An error occurred while getting commit status: %v", err)
+			goto wait
+		}
+
+		state = *status.State
+		log.Printf("Overall status: %s", state)
+
+		switch state {
+		case "failure":
+			if retryCount >= 2 {
+				log.Fatal("The PR has failed twice after applying the Kokoro labels. Failing the script.")
+			}
+			log.Println("Some checks have failed. Retrying the tests...")
+			_, _, err := client.Issues.AddLabelsToIssue(ctx, owner, repo, prNumber, labelsToAdd)
+			if err != nil {
+				log.Printf("An error occurred while adding labels: %v", err)
+			}
+			retryCount++
+		case "success":
+			log.Println("All checks have passed. Merging the pull request...")
+			commitMessage := fmt.Sprintf("Merge pull request #%d from %s/%s", prNumber, owner, repo)
+			mergeResult, _, err := client.PullRequests.Merge(ctx, owner, repo, prNumber, commitMessage, &github.PullRequestOptions{
+				MergeMethod: "squash",
+			})
+			if err != nil {
+				log.Fatalf("Failed to merge PR: %v", err)
+			}
+			log.Printf("Successfully squashed and merged PR #%d: %s", prNumber, *mergeResult.Message)
+			return // Exit the program on success
+		case "pending":
+			log.Println("Some checks are still pending. Waiting for them to complete.")
+		default:
+			log.Printf("Unknown state: %s. No action taken.", state)
+		}
+
+	wait:
+		log.Println("Waiting for 1 minute before retrying...")
+		time.Sleep(60 * time.Second)
+	}
+}