plugins: add new plugin for linking and unlinking issues to a PR

cmd/hook/plugin-imports/plugin-imports.go

@@ -38,6 +38,7 @@ import (
 	_ "sigs.k8s.io/prow/pkg/plugins/help"
 	_ "sigs.k8s.io/prow/pkg/plugins/hold"
 	_ "sigs.k8s.io/prow/pkg/plugins/invalidcommitmsg"
+	_ "sigs.k8s.io/prow/pkg/plugins/issue-management"
 	_ "sigs.k8s.io/prow/pkg/plugins/jira"
 	_ "sigs.k8s.io/prow/pkg/plugins/label"
 	_ "sigs.k8s.io/prow/pkg/plugins/lgtm"

pkg/hook/plugin-imports/plugin-imports.go

@@ -38,6 +38,7 @@ import (
 	_ "sigs.k8s.io/prow/pkg/plugins/help"
 	_ "sigs.k8s.io/prow/pkg/plugins/hold"
 	_ "sigs.k8s.io/prow/pkg/plugins/invalidcommitmsg"
+	_ "sigs.k8s.io/prow/pkg/plugins/issue-management"
 	_ "sigs.k8s.io/prow/pkg/plugins/jira"
 	_ "sigs.k8s.io/prow/pkg/plugins/label"
 	_ "sigs.k8s.io/prow/pkg/plugins/lgtm"

pkg/plugins/issue-management/issue_management.go

@@ -0,0 +1,90 @@
+/*
+Copyright 2025 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 issuemanagement implements issue management commands.
+package issuemanagement
+
+import (
+	"regexp"
+
+	"github.com/sirupsen/logrus"
+	"sigs.k8s.io/prow/pkg/config"
+	"sigs.k8s.io/prow/pkg/github"
+	"sigs.k8s.io/prow/pkg/pluginhelp"
+	"sigs.k8s.io/prow/pkg/plugins"
+)
+
+const pluginName = "issue-management"
+
+var (
+	linkIssueRegex   = regexp.MustCompile(`(?mi)^/link-issue((?: +(?:\d+|[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+#\d+))+)\b`)
+	unlinkIssueRegex = regexp.MustCompile(`(?mi)^/unlink-issue((?: +(?:\d+|[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+#\d+))+)\b`)
+)
+
+type githubClient interface {
+	CreateComment(org, repo string, number int, comment string) error
+	GetIssue(org, repo string, number int) (*github.Issue, error)
+	GetPullRequest(org, repo string, number int) (*github.PullRequest, error)
+	GetRepo(org, name string) (github.FullRepo, error)
+	IsMember(org, user string) (bool, error)
+	UpdatePullRequest(org, repo string, number int, title, body *string, open *bool, branch *string, canModify *bool) error
+}
+
+func helpProvider(_ *plugins.Configuration, _ []config.OrgRepo) (*pluginhelp.PluginHelp, error) {
+	pluginHelp := &pluginhelp.PluginHelp{
+		Description: "The issue management plugin provides commands for linking and unlinking issues to a PR.",
+	}
+	pluginHelp.AddCommand(pluginhelp.Command{
+		Usage:       "/link-issue <issue(s)>",
+		Description: "Links issue(s) to a PR in the same or different repo.",
+		WhoCanUse:   "Org members",
+		Examples:    []string{"/link-issue 1234", "/link-issue org/repo#789"},
+	})
+	pluginHelp.AddCommand(pluginhelp.Command{
+		Usage:       "/unlink-issue <issue(s)>",
+		Description: "Unlinks issue(s) from a PR in the same or different repo.",
+		WhoCanUse:   "Org members",
+		Examples:    []string{"/unlink-issue 1234", "/unlink-issue org/repo#789"},
+	})
+	return pluginHelp, nil
+}
+
+func init() {
+	plugins.RegisterGenericCommentHandler(pluginName, handleGenericComment, helpProvider)
+}
+
+func handleGenericComment(pc plugins.Agent, e github.GenericCommentEvent) error {
+	return handleIssues(pc.GitHubClient, pc.Logger.WithFields(logrus.Fields{
+		"org":    e.Repo.Owner.Login,
+		"repo":   e.Repo.Name,
+		"number": e.Number,
+		"user":   e.User.Login,
+	}), e)
+}
+
+func handleIssues(gc githubClient, log *logrus.Entry, e github.GenericCommentEvent) error {
+
+	switch {
+	case linkIssueRegex.MatchString(e.Body):
+		log.Info("Handling link issue command")
+		return handleLinkIssue(gc, log, e, true)
+	case unlinkIssueRegex.MatchString(e.Body):
+		log.Info("Handling unlink issue command")
+		return handleLinkIssue(gc, log, e, false)
+	default:
+		return nil
+	}
+}

pkg/plugins/issue-management/link-issue.go

@@ -0,0 +1,218 @@
+/*
+Copyright 2025 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.
+*/
+
+// The `/link-issue` and `/unlink-issue` command allows
+// members of the org to link and unlink issues to PRs.
+package issuemanagement
+
+import (
+	"fmt"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	"sigs.k8s.io/prow/pkg/github"
+	"sigs.k8s.io/prow/pkg/plugins"
+)
+
+var (
+	fixesRegex = regexp.MustCompile(`(?i)^fixes\s+(.*)$`)
+)
+
+type IssueRef struct {
+	Org  string
+	Repo string
+	Num  int
+}
+
+func handleLinkIssue(gc githubClient, log *logrus.Entry, e github.GenericCommentEvent, linkIssue bool) error {
+	org := e.Repo.Owner.Login
+	repo := e.Repo.Name
+	number := e.Number
+	user := e.User.Login
+
+	if !e.IsPR || e.Action != github.GenericCommentActionCreated {
+		return gc.CreateComment(org, repo, number, plugins.FormatResponseRaw(
+			e.Body, e.HTMLURL, user, "This command can only be used on pull requests."))
+	}
+
+	isMember, err := gc.IsMember(org, user)
+	if err != nil {
+		return fmt.Errorf("unable to fetch if %s is an org member of %s: %w", user, org, err)
+	}
+	if !isMember {
+		return gc.CreateComment(org, repo, number, plugins.FormatResponseRaw(
+			e.Body, e.HTMLURL, user, "You must be an org member to use this command."))
+	}
+
+	regex := linkIssueRegex
+	if !linkIssue {
+		regex = unlinkIssueRegex
+	}
+
+	matches := regex.FindStringSubmatch(e.Body)
+	if len(matches) == 0 {
+		return nil
+	}
+
+	issues := strings.Fields(matches[1])
+	if len(issues) == 0 {
+		log.Info("No issue references provided in the comment.")
+		return nil
+	}
+
+	var issueRefs []string
+	for _, issue := range issues {
+		issueRef, err := parseIssueRef(issue, org, repo)
+		if err != nil {
+			log.Debugf("Skipping invalid issue: %s", issue)
+			continue
+		}
+
+		// If repo or org of the issue reference is different from the one in which the PR is created, check if it exists
+		if org != issueRef.Org || repo != issueRef.Repo {
+			if _, err := gc.GetRepo(org, repo); err != nil {
+				return fmt.Errorf("failed to get repo: %w", err)
+			}
+		}
+
+		// Verify if the issue exists
+		fetchedIssue, err := gc.GetIssue(issueRef.Org, issueRef.Repo, issueRef.Num)
+		if err != nil {
+			return fmt.Errorf("failed to get issue: %w", err)
+		}
+		if fetchedIssue.IsPullRequest() {
+			response := fmt.Sprintf("Skipping #%d of repo **%s** and org **%s** as it is a *pull request*.", fetchedIssue.Number, issueRef.Repo, issueRef.Org)
+			if err := gc.CreateComment(org, repo, number, plugins.FormatResponseRaw(e.Body, e.HTMLURL, user, response)); err != nil {
+				log.WithError(err).Error("Failed to leave comment")
+			}
+			continue
+		}
+		issueRefs = append(issueRefs, formatIssueRef(issueRef, org, repo))
+	}
+
+	if len(issueRefs) == 0 {
+		log.Info("No valid issues to process.")
+		return nil
+	}
+
+	pr, err := gc.GetPullRequest(org, repo, number)
+	if err != nil {
+		return fmt.Errorf("failed to get PR: %w", err)
+	}
+
+	newBody := updateFixesLine(pr.Body, issueRefs, linkIssue)
+	if newBody == pr.Body {
+		log.Debug("PR body is already up-to-date. No changes needed.")
+		return nil
+	}
+
+	if err := gc.UpdatePullRequest(org, repo, number, nil, &newBody, nil, nil, nil); err != nil {
+		return fmt.Errorf("failed to update PR body: %w", err)
+	}
+
+	log.Infof("Successfully updated the PR body")
+	return nil
+}
+
+func parseIssueRef(issue, defaultOrg, defaultRepo string) (*IssueRef, error) {
+	// Handling single issue references
+	if num, err := strconv.Atoi(issue); err == nil {
+		return &IssueRef{Org: defaultOrg, Repo: defaultRepo, Num: num}, nil
+	}
+
+	// Handling issue references in format org/repo#issue-number
+	if !strings.Contains(issue, "/") {
+		return nil, fmt.Errorf("unrecognized issue reference: %s", issue)
+	}
+
+	parts := strings.Split(issue, "#")
+	if len(parts) != 2 {
+		return nil, fmt.Errorf("invalid issue ref: %s", issue)
+	}
+	orgRepo := strings.Split(parts[0], "/")
+	if len(orgRepo) != 2 {
+		return nil, fmt.Errorf("invalid org/repo format: %s", issue)
+	}
+	num, err := strconv.Atoi(parts[1])
+	if err != nil {
+		return nil, fmt.Errorf("invalid issue number: %s", issue)
+	}
+	return &IssueRef{Org: orgRepo[0], Repo: orgRepo[1], Num: num}, nil
+
+}
+
+func formatIssueRef(ref *IssueRef, defaultOrg, defaultRepo string) string {
+	if ref.Org == defaultOrg && ref.Repo == defaultRepo {
+		return fmt.Sprintf("#%d", ref.Num)
+	}
+	return fmt.Sprintf("%s/%s#%d", ref.Org, ref.Repo, ref.Num)
+}
+
+func updateFixesLine(body string, issueRefs []string, add bool) string {
+	lines := strings.Split(body, "\n")
+	var fixesLine string
+	fixesIndex := -1
+	issueList := make(map[string]bool)
+
+	// Find and parse existing Fixes line
+	for i, line := range lines {
+		if m := fixesRegex.FindStringSubmatch(line); m != nil {
+			fixesIndex = i
+			for _, i := range strings.Fields(m[1]) {
+				issueList[i] = true
+			}
+			break
+		}
+	}
+
+	for _, ref := range issueRefs {
+		if add {
+			issueList[ref] = true
+		} else {
+			delete(issueList, ref)
+		}
+	}
+
+	if len(issueList) == 0 {
+		// All linked issues have been removed, the fixes line can be deleted from the PR body.
+		if fixesIndex != -1 {
+			lines = append(lines[:fixesIndex], lines[fixesIndex+1:]...)
+		}
+		return strings.Join(lines, "\n")
+	}
+
+	var newIssueRefs []string
+	for ref := range issueList {
+		newIssueRefs = append(newIssueRefs, ref)
+	}
+
+	sort.Strings(newIssueRefs)
+	fixesLine = "Fixes " + strings.Join(newIssueRefs, " ")
+
+	if fixesIndex >= 0 {
+		lines[fixesIndex] = fixesLine
+	} else {
+		if len(lines) > 0 && lines[len(lines)-1] != "" {
+			lines = append(lines, "")
+		}
+		lines = append(lines, fixesLine)
+	}
+
+	return strings.Join(lines, "\n")
+}