Add Contributed backport command (#22643)

This PR provides a contributed backport command to help create backports
for Gitea.

It represents a significant improvement on my previously described
shell-script.

It can be installed using `go install contrib/backport/backport.go`.

Signed-off-by: Andrew Thornton <art27@cantab.net>
This commit is contained in:
zeripath 2023-01-31 22:10:54 +00:00 committed by GitHub
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commit f1f0430f9f
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@ -267,26 +267,10 @@ with the rest of the summary matching the original PR. Similarly for frontports
--- ---
The below is a script that may be helpful in creating backports. YMMV. A command to help create backports can be found in `contrib/backport` and can be installed (from inside the gitea repo root directory) using:
```bash ```bash
#!/bin/sh go install contrib/backport/backport.go
PR="$1"
SHA="$2"
VERSION="$3"
if [ -z "$SHA" ]; then
SHA=$(gh api /repos/go-gitea/gitea/pulls/$PR -q '.merge_commit_sha')
fi
if [ -z "$VERSION" ]; then
VERSION="v1.16"
fi
echo git checkout origin/release/"$VERSION" -b backport-$PR-$VERSION
git checkout origin/release/"$VERSION" -b backport-$PR-$VERSION
git cherry-pick $SHA && git commit --amend && git push zeripath backport-$PR-$VERSION && xdg-open https://github.com/go-gitea/gitea/compare/release/"$VERSION"...zeripath:backport-$PR-$VERSION
``` ```
## Developer Certificate of Origin (DCO) ## Developer Certificate of Origin (DCO)

41
contrib/backport/README Normal file
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@ -0,0 +1,41 @@
`backport`
==========
`backport` is a command to help create backports of PRs. It backports a
provided PR from main on to a released version.
It will create a backport branch, cherry-pick the PR's merge commit, adjust
the commit message and then push this back up to your fork's remote.
The default version will read from `docs/config.yml`. You can override this
using the option `--version`.
The upstream branches will be fetched, using the remote `origin`. This can
be overrided using `--upstream`, and fetching can be avoided using
`--no-fetch`.
By default the branch created will be called `backport-$PR-$VERSION`. You
can override this using the option `--backport-branch`. This branch will
be created from `--release-branch` which is `release/$(VERSION)`
by default and will be pulled from `$(UPSTREAM)`.
The merge-commit as determined by the github API will be used as the SHA to
cherry-pick. You can override this using `--cherry-pick`.
The commit message will be amended to add the `Backport` header.
`--no-amend-message` can be set to stop this from happening.
If cherry-pick is successful the backported branch will be pushed up to your
fork using your remote. These will be determined using `git remote -v`. You
can set your fork name using `--fork-user` and your remote name using
`--remote`. You can avoid pushing using `--no-push`.
If the push is successful, `xdg-open` will be called to open a backport url.
You can stop this using `--no-xdg-open`.
Installation
============
```bash
go install contrib/backport/backport.go
```

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@ -0,0 +1,438 @@
// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package main
import (
"context"
"fmt"
"log"
"net/http"
"os"
"os/exec"
"os/signal"
"path"
"strconv"
"strings"
"syscall"
"github.com/google/go-github/v45/github"
"github.com/urfave/cli"
"gopkg.in/yaml.v3"
)
const defaultVersion = "v1.18" // to backport to
func main() {
app := cli.NewApp()
app.Name = "backport"
app.Usage = "Backport provided PR-number on to the current or previous released version"
app.Description = `Backport will look-up the PR in Gitea's git log and attempt to cherry-pick it on the current version`
app.ArgsUsage = "<PR-to-backport>"
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "version",
Usage: "Version branch to backport on to",
},
cli.StringFlag{
Name: "upstream",
Value: "origin",
Usage: "Upstream remote for the Gitea upstream",
},
cli.StringFlag{
Name: "release-branch",
Value: "",
Usage: "Release branch to backport on. Will default to release/<version>",
},
cli.StringFlag{
Name: "cherry-pick",
Usage: "SHA to cherry-pick as backport",
},
cli.StringFlag{
Name: "backport-branch",
Usage: "Backport branch to backport on to (default: backport-<pr>-<version>",
},
cli.StringFlag{
Name: "remote",
Value: "",
Usage: "Remote for your fork of the Gitea upstream",
},
cli.StringFlag{
Name: "fork-user",
Value: "",
Usage: "Forked user name on Github",
},
cli.BoolFlag{
Name: "no-fetch",
Usage: "Set this flag to prevent fetch of remote branches",
},
cli.BoolFlag{
Name: "no-amend-message",
Usage: "Set this flag to prevent automatic amendment of the commit message",
},
cli.BoolFlag{
Name: "no-push",
Usage: "Set this flag to prevent pushing the backport up to your fork",
},
cli.BoolFlag{
Name: "no-xdg-open",
Usage: "Set this flag to not use xdg-open to open the PR URL",
},
}
cli.AppHelpTemplate = `NAME:
{{.Name}} - {{.Usage}}
USAGE:
{{.HelpName}} {{if .VisibleFlags}}[options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}
{{if len .Authors}}
AUTHOR:
{{range .Authors}}{{ . }}{{end}}
{{end}}{{if .Commands}}
OPTIONS:
{{range .VisibleFlags}}{{.}}
{{end}}{{end}}
`
app.Action = runBackport
if err := app.Run(os.Args); err != nil {
fmt.Fprintf(os.Stderr, "Unable to backport: %v\n", err)
}
}
func runBackport(c *cli.Context) error {
ctx, cancel := installSignals()
defer cancel()
version := c.String("version")
if version == "" {
version = readVersion()
}
if version == "" {
version = defaultVersion
}
upstream := c.String("upstream")
if upstream == "" {
upstream = "origin"
}
forkUser := c.String("fork-user")
remote := c.String("remote")
if remote == "" && !c.Bool("--no-push") {
var err error
remote, forkUser, err = determineRemote(ctx, forkUser)
if err != nil {
return err
}
}
upstreamReleaseBranch := c.String("release-branch")
if upstreamReleaseBranch == "" {
upstreamReleaseBranch = path.Join("release", version)
}
localReleaseBranch := path.Join(upstream, upstreamReleaseBranch)
args := c.Args()
if len(args) == 0 {
return fmt.Errorf("no PR number provided\nProvide a PR number to backport")
} else if len(args) != 1 {
return fmt.Errorf("multiple PRs provided %v\nOnly a single PR can be backported at a time", args)
}
pr := args[0]
backportBranch := c.String("backport-branch")
if backportBranch == "" {
backportBranch = "backport-" + pr + "-" + version
}
fmt.Printf("* Backporting %s to %s as %s\n", pr, localReleaseBranch, backportBranch)
sha := c.String("cherry-pick")
if sha == "" {
var err error
sha, err = determineSHAforPR(ctx, pr)
if err != nil {
return err
}
}
if sha == "" {
return fmt.Errorf("unable to determine sha for cherry-pick of %s", pr)
}
if !c.Bool("no-fetch") {
if err := fetchRemoteAndMain(ctx, upstream, upstreamReleaseBranch); err != nil {
return err
}
}
if err := checkoutBackportBranch(ctx, backportBranch, localReleaseBranch); err != nil {
return err
}
if err := cherrypick(ctx, sha); err != nil {
return err
}
if !c.Bool("no-amend-message") {
if err := amendCommit(ctx, pr); err != nil {
return err
}
}
if !c.Bool("no-push") {
url := "https://github.com/go-gitea/gitea/compare/" + upstreamReleaseBranch + "..." + forkUser + ":" + backportBranch
if err := gitPushUp(ctx, remote, backportBranch); err != nil {
return err
}
if !c.Bool("no-xdg-open") {
if err := xdgOpen(ctx, url); err != nil {
return err
}
} else {
fmt.Printf("* Navigate to %s to open PR\n", url)
}
}
return nil
}
func xdgOpen(ctx context.Context, url string) error {
fmt.Printf("* `xdg-open %s`\n", url)
out, err := exec.CommandContext(ctx, "xdg-open", url).Output()
if err != nil {
fmt.Fprintf(os.Stderr, "%s", string(out))
return fmt.Errorf("unable to xdg-open to %s: %w", url, err)
}
return nil
}
func gitPushUp(ctx context.Context, remote, backportBranch string) error {
fmt.Printf("* `git push -u %s %s`\n", remote, backportBranch)
out, err := exec.CommandContext(ctx, "git", "push", "-u", remote, backportBranch).Output()
if err != nil {
fmt.Fprintf(os.Stderr, "%s", string(out))
return fmt.Errorf("unable to push up to %s: %w", remote, err)
}
return nil
}
func amendCommit(ctx context.Context, pr string) error {
fmt.Printf("* Amending commit to prepend `Backport #%s` to body\n", pr)
out, err := exec.CommandContext(ctx, "git", "log", "-1", "--pretty=format:%B").Output()
if err != nil {
fmt.Fprintf(os.Stderr, "%s", string(out))
return fmt.Errorf("unable to get last log message: %w", err)
}
parts := strings.SplitN(string(out), "\n", 2)
if len(parts) != 2 {
return fmt.Errorf("unable to interpret log message:\n%s", string(out))
}
subject, body := parts[0], parts[1]
if !strings.HasSuffix(subject, " (#"+pr+")") {
subject = subject + " (#" + pr + ")"
}
out, err = exec.CommandContext(ctx, "git", "commit", "--amend", "-m", subject+"\n\nBackport #"+pr+"\n"+body).Output()
if err != nil {
fmt.Fprintf(os.Stderr, "%s", string(out))
return fmt.Errorf("unable to amend last log message: %w", err)
}
return nil
}
func cherrypick(ctx context.Context, sha string) error {
// Check if a CHERRY_PICK_HEAD exists
if _, err := os.Stat(".git/CHERRY_PICK_HEAD"); err == nil {
// Assume that we are in the middle of cherry-pick - continue it
fmt.Println("* Attempting git cherry-pick --continue")
out, err := exec.CommandContext(ctx, "git", "cherry-pick", "--continue").Output()
if err != nil {
fmt.Fprintf(os.Stderr, "git cherry-pick --continue failed:\n%s\n", string(out))
return fmt.Errorf("unable to continue cherry-pick: %w", err)
}
return nil
}
fmt.Printf("* Attempting git cherry-pick %s\n", sha)
out, err := exec.CommandContext(ctx, "git", "cherry-pick", sha).Output()
if err != nil {
fmt.Fprintf(os.Stderr, "git cherry-pick %s failed:\n%s\n", sha, string(out))
return fmt.Errorf("git cherry-pick %s failed: %w", sha, err)
}
return nil
}
func checkoutBackportBranch(ctx context.Context, backportBranch, releaseBranch string) error {
out, err := exec.CommandContext(ctx, "git", "branch", "--show-current").Output()
if err != nil {
return fmt.Errorf("unable to check current branch %w", err)
}
currentBranch := strings.TrimSpace(string(out))
fmt.Printf("* Current branch is %s\n", currentBranch)
if currentBranch == backportBranch {
fmt.Printf("* Current branch is %s - not checking out\n", currentBranch)
return nil
}
if _, err := exec.CommandContext(ctx, "git", "rev-list", "-1", backportBranch).Output(); err == nil {
fmt.Printf("* Branch %s already exists. Checking it out...\n", backportBranch)
return exec.CommandContext(ctx, "git", "checkout", "-f", backportBranch).Run()
}
fmt.Printf("* `git checkout -b %s %s`\n", backportBranch, releaseBranch)
return exec.CommandContext(ctx, "git", "checkout", "-b", backportBranch, releaseBranch).Run()
}
func fetchRemoteAndMain(ctx context.Context, remote, releaseBranch string) error {
fmt.Printf("* `git fetch %s main`\n", remote)
out, err := exec.CommandContext(ctx, "git", "fetch", remote, "main").Output()
if err != nil {
fmt.Println(string(out))
return fmt.Errorf("unable to fetch %s from %s: %w", "main", remote, err)
}
fmt.Println(string(out))
fmt.Printf("* `git fetch %s %s`\n", remote, releaseBranch)
out, err = exec.CommandContext(ctx, "git", "fetch", remote, releaseBranch).Output()
if err != nil {
fmt.Println(string(out))
return fmt.Errorf("unable to fetch %s from %s: %w", releaseBranch, remote, err)
}
fmt.Println(string(out))
return nil
}
func determineRemote(ctx context.Context, forkUser string) (string, string, error) {
out, err := exec.CommandContext(ctx, "git", "remote", "-v").Output()
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to list git remotes:\n%s\n", string(out))
return "", "", fmt.Errorf("unable to determine forked remote: %w", err)
}
lines := strings.Split(string(out), "\n")
for _, line := range lines {
fields := strings.Split(line, "\t")
name, remote := fields[0], fields[1]
// only look at pushers
if !strings.HasSuffix(remote, " (push)") {
continue
}
// only look at github.com pushes
if !strings.Contains(remote, "github.com") {
continue
}
// ignore go-gitea/gitea
if strings.Contains(remote, "go-gitea/gitea") {
continue
}
if !strings.Contains(remote, forkUser) {
continue
}
if strings.HasPrefix(remote, "git@github.com:") {
forkUser = strings.TrimPrefix(remote, "git@github.com:")
} else if strings.HasPrefix(remote, "https://github.com/") {
forkUser = strings.TrimPrefix(remote, "https://github.com/")
} else if strings.HasPrefix(remote, "https://www.github.com/") {
forkUser = strings.TrimPrefix(remote, "https://www.github.com/")
} else if forkUser == "" {
return "", "", fmt.Errorf("unable to extract forkUser from remote %s: %s", name, remote)
}
idx := strings.Index(forkUser, "/")
if idx >= 0 {
forkUser = forkUser[:idx]
}
return name, forkUser, nil
}
return "", "", fmt.Errorf("unable to find appropriate remote in:\n%s", string(out))
}
func readVersion() string {
bs, err := os.ReadFile("docs/config.yaml")
if err != nil {
if err == os.ErrNotExist {
log.Println("`docs/config.yaml` not present")
return ""
}
fmt.Fprintf(os.Stderr, "Unable to read `docs/config.yaml`: %v\n", err)
return ""
}
type params struct {
Version string
}
type docConfig struct {
Params params
}
dc := &docConfig{}
if err := yaml.Unmarshal(bs, dc); err != nil {
fmt.Fprintf(os.Stderr, "Unable to read `docs/config.yaml`: %v\n", err)
return ""
}
if dc.Params.Version == "" {
fmt.Fprintf(os.Stderr, "No version in `docs/config.yaml`")
return ""
}
version := dc.Params.Version
if version[0] != 'v' {
version = "v" + version
}
split := strings.SplitN(version, ".", 3)
return strings.Join(split[:2], ".")
}
func determineSHAforPR(ctx context.Context, prStr string) (string, error) {
prNum, err := strconv.Atoi(prStr)
if err != nil {
return "", err
}
client := github.NewClient(http.DefaultClient)
pr, _, err := client.PullRequests.Get(ctx, "go-gitea", "gitea", prNum)
if err != nil {
return "", err
}
if pr.Merged == nil || !*pr.Merged {
return "", fmt.Errorf("PR #%d is not yet merged - cannot determine sha to backport", prNum)
}
if pr.MergeCommitSHA != nil {
return *pr.MergeCommitSHA, nil
}
return "", nil
}
func installSignals() (context.Context, context.CancelFunc) {
ctx, cancel := context.WithCancel(context.Background())
go func() {
// install notify
signalChannel := make(chan os.Signal, 1)
signal.Notify(
signalChannel,
syscall.SIGINT,
syscall.SIGTERM,
)
select {
case <-signalChannel:
case <-ctx.Done():
}
cancel()
signal.Reset()
}()
return ctx, cancel
}