[WIP] [Feature] Implement issue reference cross comment

models/issue.go

@@ -1225,6 +1225,16 @@ func NewIssue(repo *Repository, issue *Issue, labelIDs []int64, assigneeIDs []in
 		go HookQueue.Add(issue.RepoID)
 	}
 
+	err = FindAndCreateIssueRef(issue.Poster, repo, issue, issue.Content)
+	if err != nil {
+		return err
+	}
+
+	err = FindAndCreateIssueRef(issue.Poster, repo, issue, issue.Title)
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 

models/issue_comment.go

@@ -8,6 +8,7 @@ package models
 
 import (
 	"fmt"
+	"html"
 	"strings"
 
 	"code.gitea.io/gitea/modules/git"
@@ -830,6 +831,11 @@ func CreateIssueComment(doer *User, repo *Repository, issue *Issue, content stri
 		return nil, fmt.Errorf("CreateComment: %v", err)
 	}
 
+	err = FindAndCreateIssueRef(doer, repo, issue, content)
+	if err != nil {
+		return nil, err
+	}
+
 	mode, _ := AccessLevel(doer, repo)
 	if err = PrepareWebhooks(repo, HookEventIssueComment, &api.IssueCommentPayload{
 		Action:     api.HookIssueCommentCreated,
@@ -845,6 +851,51 @@ func CreateIssueComment(doer *User, repo *Repository, issue *Issue, content stri
 	return comment, nil
 }
 
+// FindAndCreateIssueRef Search message for issue ref and create cross ref comment
+func FindAndCreateIssueRef(doer *User, repo *Repository, issue *Issue, message string) error {
+	refMarked := make(map[int64]bool)
+	var refRepo *Repository
+	var err error
+	for _, m := range issueReferenceKeywordsPat.FindAllStringSubmatch(message, -1) {
+		if len(m[3]) == 0 {
+			continue
+		}
+		ref := m[3]
+
+		// issue is from another repo
+		if len(m[1]) > 0 && len(m[2]) > 0 {
+			refRepo, err = GetRepositoryFromMatch(m[1], m[2])
+			if err != nil {
+				continue
+			}
+		} else {
+			refRepo = repo
+		}
+		refIssue, err := getIssueFromRef(refRepo, ref)
+		if err != nil {
+			return err
+		}
+
+		if refIssue == nil || refMarked[refIssue.ID] {
+			continue
+		}
+		refMarked[refIssue.ID] = true
+
+		issueType := "issues"
+
+		if issue.IsPull {
+			issueType = "pull"
+		}
+
+		message := fmt.Sprintf(`<a href="%s/%s/%d">%s</a>`, repo.Link(), issueType, issue.ID, html.EscapeString(issue.Title))
+		if err = CreateIssueRefComment(doer, refRepo, refIssue, message); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // CreateRefComment creates a commit reference comment to issue.
 func CreateRefComment(doer *User, repo *Repository, issue *Issue, content, commitSHA string) error {
 	if len(commitSHA) == 0 {
@@ -874,6 +925,30 @@ func CreateRefComment(doer *User, repo *Repository, issue *Issue, content, commi
 	return err
 }
 
+// CreateIssueRefComment creates a issue reference comment to issue.
+func CreateIssueRefComment(doer *User, repo *Repository, issue *Issue, content string) error {
+	// Check if same reference from same issue has already existed.
+	has, err := x.Get(&Comment{
+		Type:    CommentTypeIssueRef,
+		IssueID: issue.ID,
+		Content: content,
+	})
+	if err != nil {
+		return fmt.Errorf("CreateIssueRefComment (check has): %v", err)
+	} else if has {
+		return nil
+	}
+
+	_, err = CreateComment(&CreateCommentOptions{
+		Type:    CommentTypeIssueRef,
+		Doer:    doer,
+		Repo:    repo,
+		Issue:   issue,
+		Content: content,
+	})
+	return err
+}
+
 // GetCommentByID returns the comment by given ID.
 func GetCommentByID(id int64) (*Comment, error) {
 	c := new(Comment)

options/locale/locale_en-US.ini

@@ -835,6 +835,7 @@ issues.reopen_comment_issue = Comment and Reopen
 issues.create_comment = Comment
 issues.closed_at = `closed <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 issues.reopened_at = `reopened <a id="%[1]s" href="#%[1]s">%[2]s</a>`
+issues.issue_ref_at = `referenced this issue from <b>%s</b>`
 issues.commit_ref_at = `referenced this issue from a commit <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 issues.poster = Poster
 issues.collaborator = Collaborator

routers/repo/issue.go

@@ -1042,6 +1042,11 @@ func UpdateIssueTitle(ctx *context.Context) {
 		return
 	}
 
+	if err := models.FindAndCreateIssueRef(ctx.User, ctx.Repo.Repository, issue, title); err != nil {
+		ctx.ServerError("FindAndCreateIssueRef", err)
+		return
+	}
+
 	notification.NotifyIssueChangeTitle(ctx.User, issue, oldTitle)
 
 	ctx.JSON(200, map[string]interface{}{
@@ -1067,6 +1072,11 @@ func UpdateIssueContent(ctx *context.Context) {
 		return
 	}
 
+	if err := models.FindAndCreateIssueRef(ctx.User, ctx.Repo.Repository, issue, content); err != nil {
+		ctx.ServerError("FindAndCreateIssueRef", err)
+		return
+	}
+
 	ctx.JSON(200, map[string]interface{}{
 		"content": string(markdown.Render([]byte(issue.Content), ctx.Query("context"), ctx.Repo.Repository.ComposeMetas())),
 	})
@@ -1339,6 +1349,11 @@ func UpdateCommentContent(ctx *context.Context) {
 		return
 	}
 
+	if err = models.FindAndCreateIssueRef(ctx.User, ctx.Repo.Repository, comment.Issue, comment.Content); err != nil {
+		ctx.ServerError("FindAndCreateIssueRef", err)
+		return
+	}
+
 	notification.NotifyUpdateComment(ctx.User, comment, oldContent)
 
 	ctx.JSON(200, map[string]interface{}{

templates/repo/issue/view_content/comments.tmpl

@@ -96,6 +96,17 @@
 			</a>
 			<span class="text grey"><a href="{{.Poster.HomeLink}}">{{.Poster.GetDisplayName}}</a> {{$.i18n.Tr "repo.issues.closed_at" .EventTag $createdStr | Safe}}</span>
 		</div>
+	{{else if eq .Type 3}}
+		<div class="event">
+			<span class="octicon octicon-bookmark issue-symbol"></span>
+			<a class="ui avatar image" href="{{.Poster.HomeLink}}">
+				<img src="{{.Poster.RelAvatarLink}}">
+			</a>
+			<span class="text grey">
+				<a href="{{.Poster.HomeLink}}">{{.Poster.GetDisplayName}}</a>
+				{{$.i18n.Tr "repo.issues.issue_ref_at" .Content | Safe}}
+			</span>
+		</div>
 	{{else if eq .Type 4}}
 		<div class="event">
 			<span class="octicon octicon-bookmark"></span>