sigs.k8s.io/prow@v0.0.0-20240503223140-c5e374dc7eb1/pkg/plugins/cherrypickunapproved/cherrypick-unapproved.go

/*
Copyright 2018 The Kubernetes Authors.

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.
*/

// Package cherrypickunapproved adds the `do-not-merge/cherry-pick-not-approved`
// label to PRs against a release branch which do not have the
// `cherry-pick-approved` label.
package cherrypickunapproved

import (
	"encoding/json"
	"fmt"
	"regexp"
	"strings"

	"github.com/sirupsen/logrus"

	"sigs.k8s.io/prow/pkg/config"
	"sigs.k8s.io/prow/pkg/github"
	"sigs.k8s.io/prow/pkg/labels"
	"sigs.k8s.io/prow/pkg/pluginhelp"
	"sigs.k8s.io/prow/pkg/plugins"
)

const (
	// PluginName defines this plugin's registered name.
	PluginName = "cherry-pick-unapproved"
)

func init() {
	plugins.RegisterPullRequestHandler(PluginName, handlePullRequest, helpProvider)
}

func helpProvider(config *plugins.Configuration, _ []config.OrgRepo) (*pluginhelp.PluginHelp, error) {
	// Only the 'Config' and Description' fields are necessary because this
	// plugin does not react to any commands.
	yamlSnippet, err := plugins.CommentMap.GenYaml(&plugins.Configuration{
		CherryPickUnapproved: plugins.CherryPickUnapproved{
			BranchRegexp: "^release-*",
			Comment:      "This is why your cherry-pick cannot be approved.",
		},
	})
	if err != nil {
		logrus.WithError(err).Warnf("cannot generate comments for %s plugin", PluginName)
	}
	pluginHelp := &pluginhelp.PluginHelp{
		Description: "Label PRs against a release branch which do not have the `cherry-pick-approved` label with the `do-not-merge/cherry-pick-not-approved` label.",
		Config: map[string]string{
			"": fmt.Sprintf(
				"The cherry-pick-unapproved plugin treats PRs against branch names satisfying the regular expression `%s` as cherry-pick PRs and adds the following comment:\n%s",
				config.CherryPickUnapproved.BranchRegexp,
				config.CherryPickUnapproved.Comment,
			),
		},
		Snippet: yamlSnippet,
	}
	return pluginHelp, nil
}

type githubClient interface {
	CreateComment(owner, repo string, number int, comment string) error
	AddLabel(owner, repo string, number int, label string) error
	RemoveLabel(owner, repo string, number int, label string) error
	GetIssueLabels(org, repo string, number int) ([]github.Label, error)
}

type commentPruner interface {
	PruneComments(shouldPrune func(github.IssueComment) bool)
}

func handlePullRequest(pc plugins.Agent, pr github.PullRequestEvent) error {
	cp, err := pc.CommentPruner()
	if err != nil {
		return err
	}
	return handlePR(
		pc.GitHubClient, pc.Logger, &pr, cp,
		pc.PluginConfig.CherryPickUnapproved.BranchRe, pc.PluginConfig.CherryPickUnapproved.Comment,
	)
}

func handlePR(gc githubClient, log *logrus.Entry, pr *github.PullRequestEvent, cp commentPruner, branchRe *regexp.Regexp, commentBody string) error {
	var (
		org    = pr.Repo.Owner.Login
		repo   = pr.Repo.Name
		branch = pr.PullRequest.Base.Ref
	)

	switch pr.Action {
	case github.PullRequestActionOpened, github.PullRequestActionReopened:
		if !branchRe.MatchString(branch) {
			return nil
		}
		return ensureLabels(gc, org, repo, pr, log, cp, commentBody)
	case github.PullRequestActionLabeled, github.PullRequestActionUnlabeled:
		if !branchRe.MatchString(branch) {
			return nil
		}
		if !(pr.Label.Name == labels.CpApproved || pr.Label.Name == labels.CpUnapproved) {
			return nil
		}
		return ensureLabels(gc, org, repo, pr, log, cp, commentBody)
	case github.PullRequestActionEdited:
		// if someone changes the base of their PR, we will get this event
		// and the changes field will list that the base SHA and ref changes
		var changes struct {
			Base struct {
				Ref struct {
					From string `json:"from"`
				} `json:"ref"`
				Sha struct {
					From string `json:"from"`
				} `json:"sha"`
			} `json:"base"`
		}
		if err := json.Unmarshal(pr.Changes, &changes); err != nil {
			// we're detecting this best-effort so we can forget about the event
			return nil
		}

		if changes.Base.Ref.From == "" {
			// PR base ref did not change, ignore the event
			return nil
		}

		if branchRe.MatchString(branch) && !branchRe.MatchString(changes.Base.Ref.From) {
			// base ref changed from a branch not allowed for cherry-picks to a branch that is allowed for cherry-picks
			return ensureLabels(gc, org, repo, pr, log, cp, commentBody)
		} else if !branchRe.MatchString(branch) && branchRe.MatchString(changes.Base.Ref.From) {
			// base ref changed from a branch allowed for cherry-picks to a branch that is not allowed for cherry-picks
			return pruneLabels(gc, org, repo, pr, log, cp, commentBody)
		}
	}

	return nil
}

func ensureLabels(gc githubClient, org string, repo string, pr *github.PullRequestEvent, log *logrus.Entry, cp commentPruner, commentBody string) error {
	issueLabels, err := gc.GetIssueLabels(org, repo, pr.Number)
	if err != nil {
		return err
	}
	hasCherryPickApprovedLabel := github.HasLabel(labels.CpApproved, issueLabels)
	hasCherryPickUnapprovedLabel := github.HasLabel(labels.CpUnapproved, issueLabels)

	// if it has the approved label,
	// remove the unapproved label (if it exists) and
	// remove any comments left by this plugin
	if hasCherryPickApprovedLabel {
		if hasCherryPickUnapprovedLabel {
			if err := gc.RemoveLabel(org, repo, pr.Number, labels.CpUnapproved); err != nil {
				log.WithError(err).Errorf("GitHub failed to remove the following label: %s", labels.CpUnapproved)
			}
		}
		cp.PruneComments(func(comment github.IssueComment) bool {
			return strings.Contains(comment.Body, commentBody)
		})
		return nil
	}

	// if it already has the unapproved label, we are done here
	if hasCherryPickUnapprovedLabel {
		return nil
	}

	// only add the label and comment if none of the approved and unapproved labels are present
	if err := gc.AddLabel(org, repo, pr.Number, labels.CpUnapproved); err != nil {
		log.WithError(err).Errorf("GitHub failed to add the following label: %s", labels.CpUnapproved)
	}

	formattedComment := plugins.FormatSimpleResponse(commentBody)
	if err := gc.CreateComment(org, repo, pr.Number, formattedComment); err != nil {
		log.WithError(err).Errorf("Failed to comment %q", formattedComment)
	}

	return nil
}

func pruneLabels(gc githubClient, org string, repo string, pr *github.PullRequestEvent, log *logrus.Entry, cp commentPruner, commentBody string) error {
	issueLabels, err := gc.GetIssueLabels(org, repo, pr.Number)
	if err != nil {
		return err
	}
	hasCherryPickApprovedLabel := github.HasLabel(labels.CpApproved, issueLabels)
	hasCherryPickUnapprovedLabel := github.HasLabel(labels.CpUnapproved, issueLabels)

	if hasCherryPickApprovedLabel {
		if err := gc.RemoveLabel(org, repo, pr.Number, labels.CpApproved); err != nil {
			log.WithError(err).Errorf("GitHub failed to remove the following label: %s", labels.CpApproved)
		}
	}

	if hasCherryPickUnapprovedLabel {
		if err := gc.RemoveLabel(org, repo, pr.Number, labels.CpUnapproved); err != nil {
			log.WithError(err).Errorf("GitHub failed to remove the following label: %s", labels.CpUnapproved)
		}
	}

	cp.PruneComments(func(comment github.IssueComment) bool {
		return strings.Contains(comment.Body, commentBody)
	})

	return nil
}