Prevent simultaneous editing of comments and issues (#31053)

fixes #22907

Tested:
- [x] issue content edit
- [x] issue content change tasklist
- [x] pull request content edit
- [x] pull request change tasklist

![issue-content-edit](a0828889-fb96-4bc4-8600-da92e3205812)

(cherry picked from commit aa92b13164e84c26be91153b6022220ce0a27720)

Conflicts:
	models/issues/comment.go
	 c7a389f2b2 [FEAT] allow setting the update date on issues and comments

	options/locale/locale_en-US.ini
	 trivial context conflicts

	routers/api/v1/repo/issue_comment.go
	routers/api/v1/repo/issue_comment_attachment.go
	services/issue/comments.go
	services/issue/content.go
         user blocking is implemented differently in Forgejo

	routers/web/repo/issue.go
	 trivial difference from 6a0750177f Allow to save empty comment
         user blocking is implemented differently in Forgejo

	templates/repo/issue/view_content/conversation.tmpl
	 templates changed a lot in Forgejo but the change is
	 trivially ported

	tests/integration/issue_test.go
	 other tests were added in the same region

	web_src/js/features/repo-issue-edit.js
	 the code is still web_src/js/features/repo-legacy.js
	 trivially ported

models/issues/comment.go

@@ -52,6 +52,8 @@ func (err ErrCommentNotExist) Unwrap() error {
 	return util.ErrNotExist
 }
 
+var ErrCommentAlreadyChanged = util.NewInvalidArgumentErrorf("the comment is already changed")
+
 // CommentType defines whether a comment is just a simple comment, an action (like close) or a reference.
 type CommentType int
 
@@ -262,6 +264,7 @@ type Comment struct {
 	Line            int64 // - previous line / + proposed line
 	TreePath        string
 	Content         string        `xorm:"LONGTEXT"`
+	ContentVersion  int           `xorm:"NOT NULL DEFAULT 0"`
 	RenderedContent template.HTML `xorm:"-"`
 
 	// Path represents the 4 lines of code cemented by this comment
@@ -1119,7 +1122,7 @@ func UpdateCommentInvalidate(ctx context.Context, c *Comment) error {
 }
 
 // UpdateComment updates information of comment.
-func UpdateComment(ctx context.Context, c *Comment, doer *user_model.User) error {
+func UpdateComment(ctx context.Context, c *Comment, contentVersion int, doer *user_model.User) error {
 	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
@@ -1139,9 +1142,15 @@ func UpdateComment(ctx context.Context, c *Comment, doer *user_model.User) error
 		// see https://codeberg.org/forgejo/forgejo/pulls/764#issuecomment-1023801
 		c.UpdatedUnix = c.Issue.UpdatedUnix
 	}
-	if _, err := sess.Update(c); err != nil {
+	c.ContentVersion = contentVersion + 1
+
+	affected, err := sess.Where("content_version = ?", contentVersion).Update(c)
+	if err != nil {
 		return err
 	}
+	if affected == 0 {
+		return ErrCommentAlreadyChanged
+	}
 	if err := c.AddCrossReferences(ctx, doer, true); err != nil {
 		return err
 	}

models/issues/issue.go

@@ -94,6 +94,8 @@ func (err ErrIssueWasClosed) Error() string {
 	return fmt.Sprintf("Issue [%d] %d was already closed", err.ID, err.Index)
 }
 
+var ErrIssueAlreadyChanged = util.NewInvalidArgumentErrorf("the issue is already changed")
+
 // Issue represents an issue or pull request of repository.
 type Issue struct {
 	ID               int64                  `xorm:"pk autoincr"`
@@ -107,6 +109,7 @@ type Issue struct {
 	Title            string                 `xorm:"name"`
 	Content          string                 `xorm:"LONGTEXT"`
 	RenderedContent  template.HTML          `xorm:"-"`
+	ContentVersion   int                    `xorm:"NOT NULL DEFAULT 0"`
 	Labels           []*Label               `xorm:"-"`
 	MilestoneID      int64                  `xorm:"INDEX"`
 	Milestone        *Milestone             `xorm:"-"`

models/issues/issue_update.go

@@ -25,17 +25,18 @@ import (
 	"xorm.io/builder"
 )
 
-// UpdateIssueCols updates cols of issue
 func UpdateIssueCols(ctx context.Context, issue *Issue, cols ...string) error {
+	_, err := UpdateIssueColsWithCond(ctx, issue, builder.NewCond(), cols...)
+	return err
+}
+
+func UpdateIssueColsWithCond(ctx context.Context, issue *Issue, cond builder.Cond, cols ...string) (int64, error) {
 	sess := db.GetEngine(ctx).ID(issue.ID)
 	if issue.NoAutoTime {
 		cols = append(cols, []string{"updated_unix"}...)
 		sess.NoAutoTime()
 	}
-	if _, err := sess.Cols(cols...).Update(issue); err != nil {
-		return err
-	}
-	return nil
+	return sess.Cols(cols...).Where(cond).Update(issue)
 }
 
 func changeIssueStatus(ctx context.Context, issue *Issue, doer *user_model.User, isClosed, isMergePull bool) (*Comment, error) {
@@ -250,7 +251,7 @@ func UpdateIssueAttachments(ctx context.Context, issueID int64, uuids []string)
 }
 
 // ChangeIssueContent changes issue content, as the given user.
-func ChangeIssueContent(ctx context.Context, issue *Issue, doer *user_model.User, content string) (err error) {
+func ChangeIssueContent(ctx context.Context, issue *Issue, doer *user_model.User, content string, contentVersion int) (err error) {
 	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
@@ -269,10 +270,16 @@ func ChangeIssueContent(ctx context.Context, issue *Issue, doer *user_model.User
 	}
 
 	issue.Content = content
+	issue.ContentVersion = contentVersion + 1
 
-	if err = UpdateIssueCols(ctx, issue, "content"); err != nil {
+	expectedContentVersion := builder.NewCond().And(builder.Eq{"content_version": contentVersion})
+	affected, err := UpdateIssueColsWithCond(ctx, issue, expectedContentVersion, "content", "content_version")
+	if err != nil {
 		return fmt.Errorf("UpdateIssueCols: %w", err)
 	}
+	if affected == 0 {
+		return ErrIssueAlreadyChanged
+	}
 
 	historyDate := timeutil.TimeStampNow()
 	if issue.NoAutoTime {

models/migrations/migrations.go

@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/models/migrations/v1_20"
 	"code.gitea.io/gitea/models/migrations/v1_21"
 	"code.gitea.io/gitea/models/migrations/v1_22"
+	"code.gitea.io/gitea/models/migrations/v1_23"
 	"code.gitea.io/gitea/models/migrations/v1_6"
 	"code.gitea.io/gitea/models/migrations/v1_7"
 	"code.gitea.io/gitea/models/migrations/v1_8"
@@ -589,6 +590,9 @@ var migrations = []Migration{
 	NewMigration("Drop wrongly created table o_auth2_application", v1_22.DropWronglyCreatedTable),
 
 	// Gitea 1.22.0-rc1 ends at 299
+
+	// v299 -> v300
+	NewMigration("Add content version to issue and comment table", v1_23.AddContentVersionToIssueAndComment),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v1_23/v299.go

@@ -0,0 +1,18 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_23 //nolint
+
+import "xorm.io/xorm"
+
+func AddContentVersionToIssueAndComment(x *xorm.Engine) error {
+	type Issue struct {
+		ContentVersion int `xorm:"NOT NULL DEFAULT 0"`
+	}
+
+	type Comment struct {
+		ContentVersion int `xorm:"NOT NULL DEFAULT 0"`
+	}
+
+	return x.Sync(new(Comment), new(Issue))
+}