Move milestone to models/issues/ (#19278)

* Move milestone to models/issues/

* Fix lint

* Fix test

* Fix lint

* Fix lint

services/issue/milestone.go

@@ -5,15 +5,68 @@
 package issue
 
 import (
+	"context"
+	"fmt"
+
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/db"
+	issues_model "code.gitea.io/gitea/models/issues"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/notification"
 )
 
+func changeMilestoneAssign(ctx context.Context, doer *user_model.User, issue *models.Issue, oldMilestoneID int64) error {
+	if err := models.UpdateIssueCols(ctx, issue, "milestone_id"); err != nil {
+		return err
+	}
+
+	if oldMilestoneID > 0 {
+		if err := issues_model.UpdateMilestoneCounters(ctx, oldMilestoneID); err != nil {
+			return err
+		}
+	}
+
+	if issue.MilestoneID > 0 {
+		if err := issues_model.UpdateMilestoneCounters(ctx, issue.MilestoneID); err != nil {
+			return err
+		}
+	}
+
+	if oldMilestoneID > 0 || issue.MilestoneID > 0 {
+		if err := issue.LoadRepo(ctx); err != nil {
+			return err
+		}
+
+		opts := &models.CreateCommentOptions{
+			Type:           models.CommentTypeMilestone,
+			Doer:           doer,
+			Repo:           issue.Repo,
+			Issue:          issue,
+			OldMilestoneID: oldMilestoneID,
+			MilestoneID:    issue.MilestoneID,
+		}
+		if _, err := models.CreateCommentCtx(ctx, opts); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // ChangeMilestoneAssign changes assignment of milestone for issue.
 func ChangeMilestoneAssign(issue *models.Issue, doer *user_model.User, oldMilestoneID int64) (err error) {
-	if err = models.ChangeMilestoneAssign(issue, doer, oldMilestoneID); err != nil {
-		return
+	ctx, committer, err := db.TxContext()
+	if err != nil {
+		return err
+	}
+	defer committer.Close()
+
+	if err = changeMilestoneAssign(ctx, doer, issue, oldMilestoneID); err != nil {
+		return err
+	}
+
+	if err = committer.Commit(); err != nil {
+		return fmt.Errorf("Commit: %v", err)
 	}
 
 	notification.NotifyIssueChangeMilestone(doer, issue, oldMilestoneID)