diff --git a/models/migrations/v136.go b/models/migrations/v136.go
index 3f718798ba8..2203f15386c 100644
--- a/models/migrations/v136.go
+++ b/models/migrations/v136.go
@@ -11,7 +11,6 @@ import (
 	"strings"
 	"time"
 
-	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -29,7 +28,9 @@ func addCommitDivergenceToPulls(x *xorm.Engine) error {
 	}
 
 	type PullRequest struct {
-		ID int64 `xorm:"pk autoincr"`
+		ID      int64 `xorm:"pk autoincr"`
+		IssueID int64 `xorm:"INDEX"`
+		Index   int64
 
 		CommitsAhead  int
 		CommitsBehind int
@@ -41,7 +42,7 @@ func addCommitDivergenceToPulls(x *xorm.Engine) error {
 		MergedCommitID string `xorm:"VARCHAR(40)"`
 	}
 
-	if err := x.Sync2(new(models.PullRequest)); err != nil {
+	if err := x.Sync2(new(PullRequest)); err != nil {
 		return fmt.Errorf("Sync2: %v", err)
 	}
 
@@ -64,7 +65,7 @@ func addCommitDivergenceToPulls(x *xorm.Engine) error {
 		if err := sess.Begin(); err != nil {
 			return err
 		}
-		var results = make([]*models.PullRequest, 0, batchSize)
+		var results = make([]*PullRequest, 0, batchSize)
 		err := sess.Where("has_merged = ?", false).OrderBy("id").Limit(batchSize, last).Find(&results)
 		if err != nil {
 			return err
diff --git a/models/migrations/v82.go b/models/migrations/v82.go
index 2daa86ab073..67bb0cb8c9e 100644
--- a/models/migrations/v82.go
+++ b/models/migrations/v82.go
@@ -6,9 +6,11 @@ package migrations
 
 import (
 	"fmt"
+	"path/filepath"
+	"strings"
 
-	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/setting"
 
 	"xorm.io/xorm"
 )
@@ -32,6 +34,16 @@ func fixReleaseSha1OnReleaseTable(x *xorm.Engine) error {
 		Name string
 	}
 
+	// UserPath returns the path absolute path of user repositories.
+	UserPath := func(userName string) string {
+		return filepath.Join(setting.RepoRootPath, strings.ToLower(userName))
+	}
+
+	// RepoPath returns repository path by given user and repository name.
+	RepoPath := func(userName, repoName string) string {
+		return filepath.Join(UserPath(userName), strings.ToLower(repoName)+".git")
+	}
+
 	// Update release sha1
 	const batchSize = 100
 	sess := x.NewSession()
@@ -87,7 +99,7 @@ func fixReleaseSha1OnReleaseTable(x *xorm.Engine) error {
 					userCache[repo.OwnerID] = user
 				}
 
-				gitRepo, err = git.OpenRepository(models.RepoPath(user.Name, repo.Name))
+				gitRepo, err = git.OpenRepository(RepoPath(user.Name, repo.Name))
 				if err != nil {
 					return err
 				}
diff --git a/models/migrations/v96.go b/models/migrations/v96.go
index 7a1684354ae..9840248f614 100644
--- a/models/migrations/v96.go
+++ b/models/migrations/v96.go
@@ -6,8 +6,8 @@ package migrations
 
 import (
 	"os"
+	"path"
 
-	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/setting"
 
 	"xorm.io/xorm"
@@ -23,6 +23,12 @@ func deleteOrphanedAttachments(x *xorm.Engine) error {
 		CommentID int64
 	}
 
+	// AttachmentLocalPath returns where attachment is stored in local file
+	// system based on given UUID.
+	AttachmentLocalPath := func(uuid string) string {
+		return path.Join(setting.AttachmentPath, uuid[0:1], uuid[1:2], uuid)
+	}
+
 	sess := x.NewSession()
 	defer sess.Close()
 
@@ -52,7 +58,7 @@ func deleteOrphanedAttachments(x *xorm.Engine) error {
 		}
 
 		for _, attachment := range attachements {
-			if err := os.RemoveAll(models.AttachmentLocalPath(attachment.UUID)); err != nil {
+			if err := os.RemoveAll(AttachmentLocalPath(attachment.UUID)); err != nil {
 				return err
 			}
 		}
diff --git a/models/migrations/v99.go b/models/migrations/v99.go
index 00b4509721e..b6f6babcee7 100644
--- a/models/migrations/v99.go
+++ b/models/migrations/v99.go
@@ -5,20 +5,25 @@
 package migrations
 
 import (
-	"code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/timeutil"
 
 	"xorm.io/xorm"
 )
 
 func addTaskTable(x *xorm.Engine) error {
+	// TaskType defines task type
+	type TaskType int
+
+	// TaskStatus defines task status
+	type TaskStatus int
+
 	type Task struct {
 		ID             int64
 		DoerID         int64 `xorm:"index"` // operator
 		OwnerID        int64 `xorm:"index"` // repo owner id, when creating, the repoID maybe zero
 		RepoID         int64 `xorm:"index"`
-		Type           structs.TaskType
-		Status         structs.TaskStatus `xorm:"index"`
+		Type           TaskType
+		Status         TaskStatus `xorm:"index"`
 		StartTime      timeutil.TimeStamp
 		EndTime        timeutil.TimeStamp
 		PayloadContent string             `xorm:"TEXT"`