diff --git a/models/fixtures/foreign_reference.yml b/models/fixtures/foreign_reference.yml
new file mode 100644
index 0000000000000..ca780a73aa0c1
--- /dev/null
+++ b/models/fixtures/foreign_reference.yml
@@ -0,0 +1 @@
+[] # empty
diff --git a/models/foreignreference/error.go b/models/foreignreference/error.go
new file mode 100644
index 0000000000000..d783a087301ea
--- /dev/null
+++ b/models/foreignreference/error.go
@@ -0,0 +1,43 @@
+// Copyright 2022 Gitea. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package foreignreference
+
+import (
+	"fmt"
+)
+
+// ErrLocalIndexNotExist represents a "LocalIndexNotExist" kind of error.
+type ErrLocalIndexNotExist struct {
+	RepoID       int64
+	ForeignIndex int64
+	Type         string
+}
+
+// ErrLocalIndexNotExist checks if an error is a ErrLocalIndexNotExist.
+func IsErrLocalIndexNotExist(err error) bool {
+	_, ok := err.(ErrLocalIndexNotExist)
+	return ok
+}
+
+func (err ErrLocalIndexNotExist) Error() string {
+	return fmt.Sprintf("repository %d has no LocalIndex for ForeignIndex %d of type %s", err.RepoID, err.ForeignIndex, err.Type)
+}
+
+// ErrForeignIndexNotExist represents a "ForeignIndexNotExist" kind of error.
+type ErrForeignIndexNotExist struct {
+	RepoID     int64
+	LocalIndex int64
+	Type       string
+}
+
+// ErrForeignIndexNotExist checks if an error is a ErrForeignIndexNotExist.
+func IsErrForeignIndexNotExist(err error) bool {
+	_, ok := err.(ErrForeignIndexNotExist)
+	return ok
+}
+
+func (err ErrForeignIndexNotExist) Error() string {
+	return fmt.Sprintf("repository %d has no ForeignIndex for LocalIndex %d of type %s", err.RepoID, err.LocalIndex, err.Type)
+}
diff --git a/models/foreignreference/foreignreference.go b/models/foreignreference/foreignreference.go
new file mode 100644
index 0000000000000..cc657a0fbec6c
--- /dev/null
+++ b/models/foreignreference/foreignreference.go
@@ -0,0 +1,32 @@
+// Copyright 2022 Gitea. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package foreignreference
+
+import (
+	"code.gitea.io/gitea/models/db"
+)
+
+// Type* are valid values for the Type field of ForeignReference
+const (
+	TypeIssue         = "issue"
+	TypePullRequest   = "pull_request"
+	TypeComment       = "comment"
+	TypeReview        = "review"
+	TypeReviewComment = "review_comment"
+	TypeRelease       = "release"
+)
+
+// ForeignReference represents external references
+type ForeignReference struct {
+	// RepoID is the first column in all indices. now we only need 2 indices: (repo, local) and (repo, foreign, type)
+	RepoID       int64  `xorm:"UNIQUE(repo_foreign_type) INDEX(repo_local)" `
+	LocalIndex   int64  `xorm:"INDEX(repo_local)"` // the resource key inside Gitea, it can be IssueIndex, or some model ID.
+	ForeignIndex string `xorm:"INDEX UNIQUE(repo_foreign_type)"`
+	Type         string `xorm:"VARCHAR(16) INDEX UNIQUE(repo_foreign_type)"`
+}
+
+func init() {
+	db.RegisterModel(new(ForeignReference))
+}
diff --git a/models/issue.go b/models/issue.go
index fd59ac0a4b495..ed94195ed1e6a 100644
--- a/models/issue.go
+++ b/models/issue.go
@@ -15,6 +15,7 @@ import (
 
 	admin_model "code.gitea.io/gitea/models/admin"
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/foreignreference"
 	"code.gitea.io/gitea/models/issues"
 	"code.gitea.io/gitea/models/perm"
 	repo_model "code.gitea.io/gitea/models/repo"
@@ -67,11 +68,12 @@ type Issue struct {
 	UpdatedUnix timeutil.TimeStamp `xorm:"INDEX updated"`
 	ClosedUnix  timeutil.TimeStamp `xorm:"INDEX"`
 
-	Attachments      []*repo_model.Attachment `xorm:"-"`
-	Comments         []*Comment               `xorm:"-"`
-	Reactions        ReactionList             `xorm:"-"`
-	TotalTrackedTime int64                    `xorm:"-"`
-	Assignees        []*user_model.User       `xorm:"-"`
+	Attachments      []*repo_model.Attachment           `xorm:"-"`
+	Comments         []*Comment                         `xorm:"-"`
+	Reactions        ReactionList                       `xorm:"-"`
+	TotalTrackedTime int64                              `xorm:"-"`
+	Assignees        []*user_model.User                 `xorm:"-"`
+	ForeignReference *foreignreference.ForeignReference `xorm:"-"`
 
 	// IsLocked limits commenting abilities to users on an issue
 	// with write access
@@ -271,6 +273,29 @@ func (issue *Issue) loadReactions(ctx context.Context) (err error) {
 	return nil
 }
 
+func (issue *Issue) loadForeignReference(ctx context.Context) (err error) {
+	if issue.ForeignReference != nil {
+		return nil
+	}
+	reference := &foreignreference.ForeignReference{
+		RepoID:     issue.RepoID,
+		LocalIndex: issue.Index,
+		Type:       foreignreference.TypeIssue,
+	}
+	has, err := db.GetEngine(ctx).Get(reference)
+	if err != nil {
+		return err
+	} else if !has {
+		return foreignreference.ErrForeignIndexNotExist{
+			RepoID:     issue.RepoID,
+			LocalIndex: issue.Index,
+			Type:       foreignreference.TypeIssue,
+		}
+	}
+	issue.ForeignReference = reference
+	return nil
+}
+
 func (issue *Issue) loadMilestone(e db.Engine) (err error) {
 	if (issue.Milestone == nil || issue.Milestone.ID != issue.MilestoneID) && issue.MilestoneID > 0 {
 		issue.Milestone, err = getMilestoneByRepoID(e, issue.RepoID, issue.MilestoneID)
@@ -332,6 +357,10 @@ func (issue *Issue) loadAttributes(ctx context.Context) (err error) {
 		}
 	}
 
+	if err = issue.loadForeignReference(ctx); err != nil && !foreignreference.IsErrForeignIndexNotExist(err) {
+		return err
+	}
+
 	return issue.loadReactions(ctx)
 }
 
@@ -1110,6 +1139,26 @@ func GetIssueByIndex(repoID, index int64) (*Issue, error) {
 	return issue, nil
 }
 
+// GetIssueByForeignIndex returns raw issue by foreign ID
+func GetIssueByForeignIndex(ctx context.Context, repoID, foreignIndex int64) (*Issue, error) {
+	reference := &foreignreference.ForeignReference{
+		RepoID:       repoID,
+		ForeignIndex: strconv.FormatInt(foreignIndex, 10),
+		Type:         foreignreference.TypeIssue,
+	}
+	has, err := db.GetEngine(ctx).Get(reference)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, foreignreference.ErrLocalIndexNotExist{
+			RepoID:       repoID,
+			ForeignIndex: foreignIndex,
+			Type:         foreignreference.TypeIssue,
+		}
+	}
+	return GetIssueByIndex(repoID, reference.LocalIndex)
+}
+
 // GetIssueWithAttrsByIndex returns issue by index in a repository.
 func GetIssueWithAttrsByIndex(repoID, index int64) (*Issue, error) {
 	issue, err := GetIssueByIndex(repoID, index)
diff --git a/models/issue_test.go b/models/issue_test.go
index 7cc0aa61b0da9..9afbce67c1f9e 100644
--- a/models/issue_test.go
+++ b/models/issue_test.go
@@ -8,11 +8,13 @@ import (
 	"context"
 	"fmt"
 	"sort"
+	"strconv"
 	"sync"
 	"testing"
 	"time"
 
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/foreignreference"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
@@ -534,3 +536,35 @@ func TestCorrectIssueStats(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, issueStats.OpenCount, issueAmount)
 }
+
+func TestIssueForeignReference(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	issue := unittest.AssertExistsAndLoadBean(t, &Issue{ID: 4}).(*Issue)
+	assert.NotEqualValues(t, issue.Index, issue.ID) // make sure they are different to avoid false positive
+
+	// it is fine for an issue to not have a foreign reference
+	err := issue.LoadAttributes()
+	assert.NoError(t, err)
+	assert.Nil(t, issue.ForeignReference)
+
+	var foreignIndex int64 = 12345
+	_, err = GetIssueByForeignIndex(context.Background(), issue.RepoID, foreignIndex)
+	assert.True(t, foreignreference.IsErrLocalIndexNotExist(err))
+
+	_, err = db.GetEngine(db.DefaultContext).Insert(&foreignreference.ForeignReference{
+		LocalIndex:   issue.Index,
+		ForeignIndex: strconv.FormatInt(foreignIndex, 10),
+		RepoID:       issue.RepoID,
+		Type:         foreignreference.TypeIssue,
+	})
+	assert.NoError(t, err)
+
+	err = issue.LoadAttributes()
+	assert.NoError(t, err)
+
+	assert.EqualValues(t, issue.ForeignReference.ForeignIndex, strconv.FormatInt(foreignIndex, 10))
+
+	found, err := GetIssueByForeignIndex(context.Background(), issue.RepoID, foreignIndex)
+	assert.NoError(t, err)
+	assert.EqualValues(t, found.Index, issue.Index)
+}
diff --git a/models/migrate.go b/models/migrate.go
index bbfba1fa1e61a..2470fd4336bd7 100644
--- a/models/migrate.go
+++ b/models/migrate.go
@@ -83,6 +83,13 @@ func insertIssue(ctx context.Context, issue *Issue) error {
 		}
 	}
 
+	if issue.ForeignReference != nil {
+		issue.ForeignReference.LocalIndex = issue.Index
+		if _, err := sess.Insert(issue.ForeignReference); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
diff --git a/models/migrate_test.go b/models/migrate_test.go
index d85dcbfeef25d..f4af7ffe373f8 100644
--- a/models/migrate_test.go
+++ b/models/migrate_test.go
@@ -5,8 +5,10 @@
 package models
 
 import (
+	"strconv"
 	"testing"
 
+	"code.gitea.io/gitea/models/foreignreference"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
@@ -45,6 +47,7 @@ func assertCreateIssues(t *testing.T, isPull bool) {
 		UserID: owner.ID,
 	}
 
+	foreignIndex := int64(12345)
 	title := "issuetitle1"
 	is := &Issue{
 		RepoID:      repo.ID,
@@ -58,11 +61,20 @@ func assertCreateIssues(t *testing.T, isPull bool) {
 		IsClosed:    true,
 		Labels:      []*Label{label},
 		Reactions:   []*Reaction{reaction},
+		ForeignReference: &foreignreference.ForeignReference{
+			ForeignIndex: strconv.FormatInt(foreignIndex, 10),
+			RepoID:       repo.ID,
+			Type:         foreignreference.TypeIssue,
+		},
 	}
 	err := InsertIssues(is)
 	assert.NoError(t, err)
 
 	i := unittest.AssertExistsAndLoadBean(t, &Issue{Title: title}).(*Issue)
+	assert.Nil(t, i.ForeignReference)
+	err = i.LoadAttributes()
+	assert.NoError(t, err)
+	assert.EqualValues(t, strconv.FormatInt(foreignIndex, 10), i.ForeignReference.ForeignIndex)
 	unittest.AssertExistsAndLoadBean(t, &Reaction{Type: "heart", UserID: owner.ID, IssueID: i.ID})
 }
 
diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 31b172a68d66f..5ed358822b689 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -373,6 +373,8 @@ var migrations = []Migration{
 	NewMigration("Increase WebAuthentication CredentialID size to 410 - NO-OPED", increaseCredentialIDTo410),
 	// v210 -> v211
 	NewMigration("v208 was completely broken - remigrate", remigrateU2FCredentials),
+	// v211 -> v212
+	NewMigration("Create ForeignReference table", createForeignReferenceTable),
 }
 
 // GetCurrentDBVersion returns the current db version
diff --git a/models/migrations/v211.go b/models/migrations/v211.go
new file mode 100644
index 0000000000000..26ccfd20376c1
--- /dev/null
+++ b/models/migrations/v211.go
@@ -0,0 +1,26 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"fmt"
+
+	"xorm.io/xorm"
+)
+
+func createForeignReferenceTable(x *xorm.Engine) error {
+	type ForeignReference struct {
+		// RepoID is the first column in all indices. now we only need 2 indices: (repo, local) and (repo, foreign, type)
+		RepoID       int64  `xorm:"UNIQUE(repo_foreign_type) INDEX(repo_local)" `
+		LocalIndex   int64  `xorm:"INDEX(repo_local)"` // the resource key inside Gitea, it can be IssueIndex, or some model ID.
+		ForeignIndex string `xorm:"INDEX UNIQUE(repo_foreign_type)"`
+		Type         string `xorm:"VARCHAR(16) INDEX UNIQUE(repo_foreign_type)"`
+	}
+
+	if err := x.Sync2(new(ForeignReference)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+	return nil
+}
diff --git a/modules/migration/comment.go b/modules/migration/comment.go
index f364ffc93a728..0447689b74cd6 100644
--- a/modules/migration/comment.go
+++ b/modules/migration/comment.go
@@ -7,6 +7,13 @@ package migration
 
 import "time"
 
+// Commentable can be commented upon
+type Commentable interface {
+	GetLocalIndex() int64
+	GetForeignIndex() int64
+	GetContext() DownloaderContext
+}
+
 // Comment is a standard comment information
 type Comment struct {
 	IssueIndex  int64 `yaml:"issue_index"`
diff --git a/modules/migration/downloader.go b/modules/migration/downloader.go
index 90e149fb1a40c..7759c96056a92 100644
--- a/modules/migration/downloader.go
+++ b/modules/migration/downloader.go
@@ -11,13 +11,6 @@ import (
 	"code.gitea.io/gitea/modules/structs"
 )
 
-// GetCommentOptions represents an options for get comment
-type GetCommentOptions struct {
-	Context  IssueContext
-	Page     int
-	PageSize int
-}
-
 // Downloader downloads the site repo information
 type Downloader interface {
 	SetContext(context.Context)
@@ -27,10 +20,11 @@ type Downloader interface {
 	GetReleases() ([]*Release, error)
 	GetLabels() ([]*Label, error)
 	GetIssues(page, perPage int) ([]*Issue, bool, error)
-	GetComments(opts GetCommentOptions) ([]*Comment, bool, error)
+	GetComments(commentable Commentable) ([]*Comment, bool, error)
+	GetAllComments(page, perPage int) ([]*Comment, bool, error)
 	SupportGetRepoComments() bool
 	GetPullRequests(page, perPage int) ([]*PullRequest, bool, error)
-	GetReviews(pullRequestContext IssueContext) ([]*Review, error)
+	GetReviews(reviewable Reviewable) ([]*Review, error)
 	FormatCloneURL(opts MigrateOptions, remoteAddr string) (string, error)
 }
 
@@ -39,3 +33,6 @@ type DownloaderFactory interface {
 	New(ctx context.Context, opts MigrateOptions) (Downloader, error)
 	GitServiceType() structs.GitServiceType
 }
+
+// DownloaderContext has opaque information only relevant to a given downloader
+type DownloaderContext interface{}
diff --git a/modules/migration/issue.go b/modules/migration/issue.go
index 984f07d8c9eed..78f648dd2db57 100644
--- a/modules/migration/issue.go
+++ b/modules/migration/issue.go
@@ -7,44 +7,26 @@ package migration
 
 import "time"
 
-// IssueContext is used to map between local and foreign issue/PR ids.
-type IssueContext interface {
-	LocalID() int64
-	ForeignID() int64
-}
-
-// BasicIssueContext is a 1:1 mapping between local and foreign ids.
-type BasicIssueContext int64
-
-// LocalID gets the local id.
-func (c BasicIssueContext) LocalID() int64 {
-	return int64(c)
-}
-
-// ForeignID gets the foreign id.
-func (c BasicIssueContext) ForeignID() int64 {
-	return int64(c)
-}
-
 // Issue is a standard issue information
 type Issue struct {
-	Number      int64        `json:"number"`
-	PosterID    int64        `yaml:"poster_id" json:"poster_id"`
-	PosterName  string       `yaml:"poster_name" json:"poster_name"`
-	PosterEmail string       `yaml:"poster_email" json:"poster_email"`
-	Title       string       `json:"title"`
-	Content     string       `json:"content"`
-	Ref         string       `json:"ref"`
-	Milestone   string       `json:"milestone"`
-	State       string       `json:"state"` // closed, open
-	IsLocked    bool         `yaml:"is_locked" json:"is_locked"`
-	Created     time.Time    `json:"created"`
-	Updated     time.Time    `json:"updated"`
-	Closed      *time.Time   `json:"closed"`
-	Labels      []*Label     `json:"labels"`
-	Reactions   []*Reaction  `json:"reactions"`
-	Assignees   []string     `json:"assignees"`
-	Context     IssueContext `yaml:"-"`
+	Number       int64             `json:"number"`
+	PosterID     int64             `yaml:"poster_id" json:"poster_id"`
+	PosterName   string            `yaml:"poster_name" json:"poster_name"`
+	PosterEmail  string            `yaml:"poster_email" json:"poster_email"`
+	Title        string            `json:"title"`
+	Content      string            `json:"content"`
+	Ref          string            `json:"ref"`
+	Milestone    string            `json:"milestone"`
+	State        string            `json:"state"` // closed, open
+	IsLocked     bool              `yaml:"is_locked" json:"is_locked"`
+	Created      time.Time         `json:"created"`
+	Updated      time.Time         `json:"updated"`
+	Closed       *time.Time        `json:"closed"`
+	Labels       []*Label          `json:"labels"`
+	Reactions    []*Reaction       `json:"reactions"`
+	Assignees    []string          `json:"assignees"`
+	ForeignIndex int64             `json:"foreign_id"`
+	Context      DownloaderContext `yaml:"-"`
 }
 
 // GetExternalName ExternalUserMigrated interface
@@ -52,3 +34,7 @@ func (i *Issue) GetExternalName() string { return i.PosterName }
 
 // GetExternalID ExternalUserMigrated interface
 func (i *Issue) GetExternalID() int64 { return i.PosterID }
+
+func (i *Issue) GetLocalIndex() int64          { return i.Number }
+func (i *Issue) GetForeignIndex() int64        { return i.ForeignIndex }
+func (i *Issue) GetContext() DownloaderContext { return i.Context }
diff --git a/modules/migration/null_downloader.go b/modules/migration/null_downloader.go
index 6192870873525..32da720f1601f 100644
--- a/modules/migration/null_downloader.go
+++ b/modules/migration/null_downloader.go
@@ -47,18 +47,23 @@ func (n NullDownloader) GetIssues(page, perPage int) ([]*Issue, bool, error) {
 	return nil, false, &ErrNotSupported{Entity: "Issues"}
 }
 
-// GetComments returns comments according the options
-func (n NullDownloader) GetComments(GetCommentOptions) ([]*Comment, bool, error) {
+// GetComments returns comments of an issue or PR
+func (n NullDownloader) GetComments(commentable Commentable) ([]*Comment, bool, error) {
 	return nil, false, &ErrNotSupported{Entity: "Comments"}
 }
 
+// GetAllComments returns paginated comments
+func (n NullDownloader) GetAllComments(page, perPage int) ([]*Comment, bool, error) {
+	return nil, false, &ErrNotSupported{Entity: "AllComments"}
+}
+
 // GetPullRequests returns pull requests according page and perPage
 func (n NullDownloader) GetPullRequests(page, perPage int) ([]*PullRequest, bool, error) {
 	return nil, false, &ErrNotSupported{Entity: "PullRequests"}
 }
 
 // GetReviews returns pull requests review
-func (n NullDownloader) GetReviews(pullRequestContext IssueContext) ([]*Review, error) {
+func (n NullDownloader) GetReviews(reviewable Reviewable) ([]*Review, error) {
 	return nil, &ErrNotSupported{Entity: "Reviews"}
 }
 
diff --git a/modules/migration/pullrequest.go b/modules/migration/pullrequest.go
index 7a681940a7eeb..eaa0dd45e2c4b 100644
--- a/modules/migration/pullrequest.go
+++ b/modules/migration/pullrequest.go
@@ -35,9 +35,14 @@ type PullRequest struct {
 	Assignees      []string
 	IsLocked       bool `yaml:"is_locked"`
 	Reactions      []*Reaction
-	Context        IssueContext `yaml:"-"`
+	ForeignIndex   int64
+	Context        DownloaderContext `yaml:"-"`
 }
 
+func (p *PullRequest) GetLocalIndex() int64          { return p.Number }
+func (p *PullRequest) GetForeignIndex() int64        { return p.ForeignIndex }
+func (p *PullRequest) GetContext() DownloaderContext { return p.Context }
+
 // IsForkPullRequest returns true if the pull request from a forked repository but not the same repository
 func (p *PullRequest) IsForkPullRequest() bool {
 	return p.Head.RepoPath() != p.Base.RepoPath()
diff --git a/modules/migration/retry_downloader.go b/modules/migration/retry_downloader.go
index 1095a26891ba9..2e40c102bea88 100644
--- a/modules/migration/retry_downloader.go
+++ b/modules/migration/retry_downloader.go
@@ -148,7 +148,7 @@ func (d *RetryDownloader) GetIssues(page, perPage int) ([]*Issue, bool, error) {
 }
 
 // GetComments returns a repository's comments with retry
-func (d *RetryDownloader) GetComments(opts GetCommentOptions) ([]*Comment, bool, error) {
+func (d *RetryDownloader) GetComments(commentable Commentable) ([]*Comment, bool, error) {
 	var (
 		comments []*Comment
 		isEnd    bool
@@ -156,7 +156,7 @@ func (d *RetryDownloader) GetComments(opts GetCommentOptions) ([]*Comment, bool,
 	)
 
 	err = d.retry(func() error {
-		comments, isEnd, err = d.Downloader.GetComments(opts)
+		comments, isEnd, err = d.Downloader.GetComments(commentable)
 		return err
 	})
 
@@ -180,14 +180,14 @@ func (d *RetryDownloader) GetPullRequests(page, perPage int) ([]*PullRequest, bo
 }
 
 // GetReviews returns pull requests reviews
-func (d *RetryDownloader) GetReviews(pullRequestContext IssueContext) ([]*Review, error) {
+func (d *RetryDownloader) GetReviews(reviewable Reviewable) ([]*Review, error) {
 	var (
 		reviews []*Review
 		err     error
 	)
 
 	err = d.retry(func() error {
-		reviews, err = d.Downloader.GetReviews(pullRequestContext)
+		reviews, err = d.Downloader.GetReviews(reviewable)
 		return err
 	})
 
diff --git a/modules/migration/review.go b/modules/migration/review.go
index 85795385e97e4..e4db33d98fd38 100644
--- a/modules/migration/review.go
+++ b/modules/migration/review.go
@@ -6,6 +6,12 @@ package migration
 
 import "time"
 
+// Reviewable can be reviewed
+type Reviewable interface {
+	GetLocalIndex() int64
+	GetForeignIndex() int64
+}
+
 // enumerate all review states
 const (
 	ReviewStatePending          = "PENDING"
diff --git a/services/migrations/codebase.go b/services/migrations/codebase.go
index be0b5d40043ac..bb74c0a49d1dd 100644
--- a/services/migrations/codebase.go
+++ b/services/migrations/codebase.go
@@ -266,17 +266,7 @@ func (d *CodebaseDownloader) GetLabels() ([]*base.Label, error) {
 }
 
 type codebaseIssueContext struct {
-	foreignID int64
-	localID   int64
-	Comments  []*base.Comment
-}
-
-func (c codebaseIssueContext) LocalID() int64 {
-	return c.localID
-}
-
-func (c codebaseIssueContext) ForeignID() int64 {
-	return c.foreignID
+	Comments []*base.Comment
 }
 
 // GetIssues returns issues, limits are not supported
@@ -402,10 +392,9 @@ func (d *CodebaseDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool,
 			Labels: []*base.Label{
 				{Name: issue.Type.Name},
 			},
+			ForeignIndex: issue.TicketID.Value,
 			Context: codebaseIssueContext{
-				foreignID: issue.TicketID.Value,
-				localID:   issue.TicketID.Value,
-				Comments:  comments[1:],
+				Comments: comments[1:],
 			},
 		})
 
@@ -418,10 +407,10 @@ func (d *CodebaseDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool,
 }
 
 // GetComments returns comments
-func (d *CodebaseDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
-	context, ok := opts.Context.(codebaseIssueContext)
+func (d *CodebaseDownloader) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
+	context, ok := commentable.GetContext().(codebaseIssueContext)
 	if !ok {
-		return nil, false, fmt.Errorf("unexpected comment context: %+v", opts.Context)
+		return nil, false, fmt.Errorf("unexpected context: %+v", commentable.GetContext())
 	}
 
 	return context.Comments, true, nil
@@ -570,10 +559,9 @@ func (d *CodebaseDownloader) GetPullRequests(page, perPage int) ([]*base.PullReq
 				SHA:      d.getHeadCommit(rawMergeRequest.TargetRef),
 				RepoName: d.repoName,
 			},
+			ForeignIndex: rawMergeRequest.ID.Value,
 			Context: codebaseIssueContext{
-				foreignID: rawMergeRequest.ID.Value,
-				localID:   number,
-				Comments:  comments[1:],
+				Comments: comments[1:],
 			},
 		})
 	}
@@ -581,16 +569,6 @@ func (d *CodebaseDownloader) GetPullRequests(page, perPage int) ([]*base.PullReq
 	return pullRequests, true, nil
 }
 
-// GetReviews returns pull requests reviews
-func (d *CodebaseDownloader) GetReviews(context base.IssueContext) ([]*base.Review, error) {
-	return []*base.Review{}, nil
-}
-
-// GetTopics return repository topics
-func (d *CodebaseDownloader) GetTopics() ([]string, error) {
-	return []string{}, nil
-}
-
 func (d *CodebaseDownloader) tryGetUser(userID int64) *codebaseUser {
 	if len(d.userMap) == 0 {
 		var rawUsers struct {
diff --git a/services/migrations/codebase_test.go b/services/migrations/codebase_test.go
index ef39b9f146b86..cb70a2bf75936 100644
--- a/services/migrations/codebase_test.go
+++ b/services/migrations/codebase_test.go
@@ -108,9 +108,7 @@ func TestCodebaseDownloadRepo(t *testing.T) {
 		},
 	}, issues)
 
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: issues[0].Context,
-	})
+	comments, _, err := downloader.GetComments(issues[0])
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
 		{
@@ -148,7 +146,7 @@ func TestCodebaseDownloadRepo(t *testing.T) {
 		},
 	}, prs)
 
-	rvs, err := downloader.GetReviews(prs[0].Context)
+	rvs, err := downloader.GetReviews(prs[0])
 	assert.NoError(t, err)
 	assert.Empty(t, rvs)
 }
diff --git a/services/migrations/gitbucket.go b/services/migrations/gitbucket.go
index c4fb0df93a7e9..92b6cac73806b 100644
--- a/services/migrations/gitbucket.go
+++ b/services/migrations/gitbucket.go
@@ -64,8 +64,3 @@ func NewGitBucketDownloader(ctx context.Context, baseURL, userName, password, to
 func (g *GitBucketDownloader) SupportGetRepoComments() bool {
 	return false
 }
-
-// GetReviews is not supported
-func (g *GitBucketDownloader) GetReviews(context base.IssueContext) ([]*base.Review, error) {
-	return nil, &base.ErrNotSupported{Entity: "Reviews"}
-}
diff --git a/services/migrations/gitea_downloader.go b/services/migrations/gitea_downloader.go
index be3c6c1202fea..3c02e112ca73e 100644
--- a/services/migrations/gitea_downloader.go
+++ b/services/migrations/gitea_downloader.go
@@ -415,22 +415,22 @@ func (g *GiteaDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, err
 		}
 
 		allIssues = append(allIssues, &base.Issue{
-			Title:       issue.Title,
-			Number:      issue.Index,
-			PosterID:    issue.Poster.ID,
-			PosterName:  issue.Poster.UserName,
-			PosterEmail: issue.Poster.Email,
-			Content:     issue.Body,
-			Milestone:   milestone,
-			State:       string(issue.State),
-			Created:     issue.Created,
-			Updated:     issue.Updated,
-			Closed:      issue.Closed,
-			Reactions:   reactions,
-			Labels:      labels,
-			Assignees:   assignees,
-			IsLocked:    issue.IsLocked,
-			Context:     base.BasicIssueContext(issue.Index),
+			Title:        issue.Title,
+			Number:       issue.Index,
+			PosterID:     issue.Poster.ID,
+			PosterName:   issue.Poster.UserName,
+			PosterEmail:  issue.Poster.Email,
+			Content:      issue.Body,
+			Milestone:    milestone,
+			State:        string(issue.State),
+			Created:      issue.Created,
+			Updated:      issue.Updated,
+			Closed:       issue.Closed,
+			Reactions:    reactions,
+			Labels:       labels,
+			Assignees:    assignees,
+			IsLocked:     issue.IsLocked,
+			ForeignIndex: issue.Index,
 		})
 	}
 
@@ -442,7 +442,7 @@ func (g *GiteaDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, err
 }
 
 // GetComments returns comments according issueNumber
-func (g *GiteaDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
+func (g *GiteaDownloader) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
 	allComments := make([]*base.Comment, 0, g.maxPerPage)
 
 	for i := 1; ; i++ {
@@ -453,26 +453,26 @@ func (g *GiteaDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comm
 		default:
 		}
 
-		comments, _, err := g.client.ListIssueComments(g.repoOwner, g.repoName, opts.Context.ForeignID(), gitea_sdk.ListIssueCommentOptions{ListOptions: gitea_sdk.ListOptions{
+		comments, _, err := g.client.ListIssueComments(g.repoOwner, g.repoName, commentable.GetForeignIndex(), gitea_sdk.ListIssueCommentOptions{ListOptions: gitea_sdk.ListOptions{
 			PageSize: g.maxPerPage,
 			Page:     i,
 		}})
 		if err != nil {
-			return nil, false, fmt.Errorf("error while listing comments for issue #%d. Error: %v", opts.Context.ForeignID(), err)
+			return nil, false, fmt.Errorf("error while listing comments for issue #%d. Error: %v", commentable.GetForeignIndex(), err)
 		}
 
 		for _, comment := range comments {
 			reactions, err := g.getCommentReactions(comment.ID)
 			if err != nil {
-				log.Warn("Unable to load comment reactions during migrating issue #%d for comment %d to %s/%s. Error: %v", opts.Context.ForeignID(), comment.ID, g.repoOwner, g.repoName, err)
+				log.Warn("Unable to load comment reactions during migrating issue #%d for comment %d to %s/%s. Error: %v", commentable.GetForeignIndex(), comment.ID, g.repoOwner, g.repoName, err)
 				if err2 := admin_model.CreateRepositoryNotice(
-					fmt.Sprintf("Unable to load reactions during migrating issue #%d for comment %d to %s/%s. Error: %v", opts.Context.ForeignID(), comment.ID, g.repoOwner, g.repoName, err)); err2 != nil {
+					fmt.Sprintf("Unable to load reactions during migrating issue #%d for comment %d to %s/%s. Error: %v", commentable.GetForeignIndex(), comment.ID, g.repoOwner, g.repoName, err)); err2 != nil {
 					log.Error("create repository notice failed: ", err2)
 				}
 			}
 
 			allComments = append(allComments, &base.Comment{
-				IssueIndex:  opts.Context.LocalID(),
+				IssueIndex:  commentable.GetLocalIndex(),
 				Index:       comment.ID,
 				PosterID:    comment.Poster.ID,
 				PosterName:  comment.Poster.UserName,
@@ -602,7 +602,7 @@ func (g *GiteaDownloader) GetPullRequests(page, perPage int) ([]*base.PullReques
 				RepoName:  g.repoName,
 				OwnerName: g.repoOwner,
 			},
-			Context: base.BasicIssueContext(pr.Index),
+			ForeignIndex: pr.Index,
 		})
 	}
 
@@ -614,7 +614,7 @@ func (g *GiteaDownloader) GetPullRequests(page, perPage int) ([]*base.PullReques
 }
 
 // GetReviews returns pull requests review
-func (g *GiteaDownloader) GetReviews(context base.IssueContext) ([]*base.Review, error) {
+func (g *GiteaDownloader) GetReviews(reviewable base.Reviewable) ([]*base.Review, error) {
 	if err := g.client.CheckServerVersionConstraint(">=1.12"); err != nil {
 		log.Info("GiteaDownloader: instance to old, skip GetReviews")
 		return nil, nil
@@ -630,7 +630,7 @@ func (g *GiteaDownloader) GetReviews(context base.IssueContext) ([]*base.Review,
 		default:
 		}
 
-		prl, _, err := g.client.ListPullReviews(g.repoOwner, g.repoName, context.ForeignID(), gitea_sdk.ListPullReviewsOptions{ListOptions: gitea_sdk.ListOptions{
+		prl, _, err := g.client.ListPullReviews(g.repoOwner, g.repoName, reviewable.GetForeignIndex(), gitea_sdk.ListPullReviewsOptions{ListOptions: gitea_sdk.ListOptions{
 			Page:     i,
 			PageSize: g.maxPerPage,
 		}})
@@ -640,7 +640,7 @@ func (g *GiteaDownloader) GetReviews(context base.IssueContext) ([]*base.Review,
 
 		for _, pr := range prl {
 
-			rcl, _, err := g.client.ListPullReviewComments(g.repoOwner, g.repoName, context.ForeignID(), pr.ID)
+			rcl, _, err := g.client.ListPullReviewComments(g.repoOwner, g.repoName, reviewable.GetForeignIndex(), pr.ID)
 			if err != nil {
 				return nil, err
 			}
@@ -666,7 +666,7 @@ func (g *GiteaDownloader) GetReviews(context base.IssueContext) ([]*base.Review,
 
 			allReviews = append(allReviews, &base.Review{
 				ID:           pr.ID,
-				IssueIndex:   context.LocalID(),
+				IssueIndex:   reviewable.GetLocalIndex(),
 				ReviewerID:   pr.Reviewer.ID,
 				ReviewerName: pr.Reviewer.UserName,
 				Official:     pr.Official,
diff --git a/services/migrations/gitea_downloader_test.go b/services/migrations/gitea_downloader_test.go
index 2c70dc421356f..dc6903e854742 100644
--- a/services/migrations/gitea_downloader_test.go
+++ b/services/migrations/gitea_downloader_test.go
@@ -198,9 +198,7 @@ func TestGiteaDownloadRepo(t *testing.T) {
 		},
 	}, issues)
 
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: base.BasicIssueContext(4),
-	})
+	comments, _, err := downloader.GetComments(&base.Issue{Number: 4, ForeignIndex: 4})
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
 		{
@@ -265,7 +263,7 @@ func TestGiteaDownloadRepo(t *testing.T) {
 		PatchURL:       "https://gitea.com/gitea/test_repo/pulls/12.patch",
 	}, prs[1])
 
-	reviews, err := downloader.GetReviews(base.BasicIssueContext(7))
+	reviews, err := downloader.GetReviews(&base.Issue{Number: 7, ForeignIndex: 7})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
diff --git a/services/migrations/gitea_uploader.go b/services/migrations/gitea_uploader.go
index 21c2dc8f8eb5d..2faa0a1f2a4dd 100644
--- a/services/migrations/gitea_uploader.go
+++ b/services/migrations/gitea_uploader.go
@@ -11,11 +11,13 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"time"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/foreignreference"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/git"
@@ -373,6 +375,12 @@ func (g *GiteaLocalUploader) CreateIssues(issues ...*base.Issue) error {
 			Labels:      labels,
 			CreatedUnix: timeutil.TimeStamp(issue.Created.Unix()),
 			UpdatedUnix: timeutil.TimeStamp(issue.Updated.Unix()),
+			ForeignReference: &foreignreference.ForeignReference{
+				LocalIndex:   issue.GetLocalIndex(),
+				ForeignIndex: strconv.FormatInt(issue.GetForeignIndex(), 10),
+				RepoID:       g.repo.ID,
+				Type:         foreignreference.TypeIssue,
+			},
 		}
 
 		if err := g.remapUser(issue, &is); err != nil {
diff --git a/services/migrations/github.go b/services/migrations/github.go
index f86ba94393b42..faf0cf0794179 100644
--- a/services/migrations/github.go
+++ b/services/migrations/github.go
@@ -446,22 +446,22 @@ func (g *GithubDownloaderV3) GetIssues(page, perPage int) ([]*base.Issue, bool,
 		}
 
 		allIssues = append(allIssues, &base.Issue{
-			Title:       *issue.Title,
-			Number:      int64(*issue.Number),
-			PosterID:    issue.GetUser().GetID(),
-			PosterName:  issue.GetUser().GetLogin(),
-			PosterEmail: issue.GetUser().GetEmail(),
-			Content:     issue.GetBody(),
-			Milestone:   issue.GetMilestone().GetTitle(),
-			State:       issue.GetState(),
-			Created:     issue.GetCreatedAt(),
-			Updated:     issue.GetUpdatedAt(),
-			Labels:      labels,
-			Reactions:   reactions,
-			Closed:      issue.ClosedAt,
-			IsLocked:    issue.GetLocked(),
-			Assignees:   assignees,
-			Context:     base.BasicIssueContext(*issue.Number),
+			Title:        *issue.Title,
+			Number:       int64(*issue.Number),
+			PosterID:     issue.GetUser().GetID(),
+			PosterName:   issue.GetUser().GetLogin(),
+			PosterEmail:  issue.GetUser().GetEmail(),
+			Content:      issue.GetBody(),
+			Milestone:    issue.GetMilestone().GetTitle(),
+			State:        issue.GetState(),
+			Created:      issue.GetCreatedAt(),
+			Updated:      issue.GetUpdatedAt(),
+			Labels:       labels,
+			Reactions:    reactions,
+			Closed:       issue.ClosedAt,
+			IsLocked:     issue.GetLocked(),
+			Assignees:    assignees,
+			ForeignIndex: int64(*issue.Number),
 		})
 	}
 
@@ -474,16 +474,12 @@ func (g *GithubDownloaderV3) SupportGetRepoComments() bool {
 }
 
 // GetComments returns comments according issueNumber
-func (g *GithubDownloaderV3) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
-	if opts.Context != nil {
-		comments, err := g.getComments(opts.Context)
-		return comments, false, err
-	}
-
-	return g.GetAllComments(opts.Page, opts.PageSize)
+func (g *GithubDownloaderV3) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
+	comments, err := g.getComments(commentable)
+	return comments, false, err
 }
 
-func (g *GithubDownloaderV3) getComments(issueContext base.IssueContext) ([]*base.Comment, error) {
+func (g *GithubDownloaderV3) getComments(commentable base.Commentable) ([]*base.Comment, error) {
 	var (
 		allComments = make([]*base.Comment, 0, g.maxPerPage)
 		created     = "created"
@@ -498,7 +494,7 @@ func (g *GithubDownloaderV3) getComments(issueContext base.IssueContext) ([]*bas
 	}
 	for {
 		g.waitAndPickClient()
-		comments, resp, err := g.getClient().Issues.ListComments(g.ctx, g.repoOwner, g.repoName, int(issueContext.ForeignID()), opt)
+		comments, resp, err := g.getClient().Issues.ListComments(g.ctx, g.repoOwner, g.repoName, int(commentable.GetForeignIndex()), opt)
 		if err != nil {
 			return nil, fmt.Errorf("error while listing repos: %v", err)
 		}
@@ -531,7 +527,7 @@ func (g *GithubDownloaderV3) getComments(issueContext base.IssueContext) ([]*bas
 			}
 
 			allComments = append(allComments, &base.Comment{
-				IssueIndex:  issueContext.LocalID(),
+				IssueIndex:  commentable.GetLocalIndex(),
 				Index:       comment.GetID(),
 				PosterID:    comment.GetUser().GetID(),
 				PosterName:  comment.GetUser().GetLogin(),
@@ -709,9 +705,9 @@ func (g *GithubDownloaderV3) GetPullRequests(page, perPage int) ([]*base.PullReq
 				RepoName:  pr.GetBase().GetRepo().GetName(),
 				OwnerName: pr.GetBase().GetUser().GetLogin(),
 			},
-			PatchURL:  pr.GetPatchURL(),
-			Reactions: reactions,
-			Context:   base.BasicIssueContext(*pr.Number),
+			PatchURL:     pr.GetPatchURL(),
+			Reactions:    reactions,
+			ForeignIndex: int64(*pr.Number),
 		})
 	}
 
@@ -777,28 +773,28 @@ func (g *GithubDownloaderV3) convertGithubReviewComments(cs []*github.PullReques
 }
 
 // GetReviews returns pull requests review
-func (g *GithubDownloaderV3) GetReviews(context base.IssueContext) ([]*base.Review, error) {
+func (g *GithubDownloaderV3) GetReviews(reviewable base.Reviewable) ([]*base.Review, error) {
 	allReviews := make([]*base.Review, 0, g.maxPerPage)
 	opt := &github.ListOptions{
 		PerPage: g.maxPerPage,
 	}
 	for {
 		g.waitAndPickClient()
-		reviews, resp, err := g.getClient().PullRequests.ListReviews(g.ctx, g.repoOwner, g.repoName, int(context.ForeignID()), opt)
+		reviews, resp, err := g.getClient().PullRequests.ListReviews(g.ctx, g.repoOwner, g.repoName, int(reviewable.GetForeignIndex()), opt)
 		if err != nil {
 			return nil, fmt.Errorf("error while listing repos: %v", err)
 		}
 		g.setRate(&resp.Rate)
 		for _, review := range reviews {
 			r := convertGithubReview(review)
-			r.IssueIndex = context.LocalID()
+			r.IssueIndex = reviewable.GetLocalIndex()
 			// retrieve all review comments
 			opt2 := &github.ListOptions{
 				PerPage: g.maxPerPage,
 			}
 			for {
 				g.waitAndPickClient()
-				reviewComments, resp, err := g.getClient().PullRequests.ListReviewComments(g.ctx, g.repoOwner, g.repoName, int(context.ForeignID()), review.GetID(), opt2)
+				reviewComments, resp, err := g.getClient().PullRequests.ListReviewComments(g.ctx, g.repoOwner, g.repoName, int(reviewable.GetForeignIndex()), review.GetID(), opt2)
 				if err != nil {
 					return nil, fmt.Errorf("error while listing repos: %v", err)
 				}
diff --git a/services/migrations/github_test.go b/services/migrations/github_test.go
index 7540037d92fab..90c1fcaef5b6b 100644
--- a/services/migrations/github_test.go
+++ b/services/migrations/github_test.go
@@ -215,9 +215,7 @@ func TestGitHubDownloadRepo(t *testing.T) {
 	}, issues)
 
 	// downloader.GetComments()
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: base.BasicIssueContext(2),
-	})
+	comments, _, err := downloader.GetComments(&base.Issue{Number: 2, ForeignIndex: 2})
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
 		{
@@ -286,7 +284,7 @@ func TestGitHubDownloadRepo(t *testing.T) {
 			Merged:         true,
 			MergedTime:     timePtr(time.Date(2019, 11, 12, 21, 39, 27, 0, time.UTC)),
 			MergeCommitSHA: "f32b0a9dfd09a60f616f29158f772cedd89942d2",
-			Context:        base.BasicIssueContext(3),
+			ForeignIndex:   3,
 		},
 		{
 			Number:     4,
@@ -333,11 +331,11 @@ func TestGitHubDownloadRepo(t *testing.T) {
 					Content:  "+1",
 				},
 			},
-			Context: base.BasicIssueContext(4),
+			ForeignIndex: 4,
 		},
 	}, prs)
 
-	reviews, err := downloader.GetReviews(base.BasicIssueContext(3))
+	reviews, err := downloader.GetReviews(&base.PullRequest{Number: 3, ForeignIndex: 3})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
@@ -369,7 +367,7 @@ func TestGitHubDownloadRepo(t *testing.T) {
 		},
 	}, reviews)
 
-	reviews, err = downloader.GetReviews(base.BasicIssueContext(4))
+	reviews, err = downloader.GetReviews(&base.PullRequest{Number: 4, ForeignIndex: 4})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
diff --git a/services/migrations/gitlab.go b/services/migrations/gitlab.go
index c05d081e9aadc..d3a034e27c52a 100644
--- a/services/migrations/gitlab.go
+++ b/services/migrations/gitlab.go
@@ -349,19 +349,9 @@ func (g *GitlabDownloader) GetReleases() ([]*base.Release, error) {
 }
 
 type gitlabIssueContext struct {
-	foreignID      int64
-	localID        int64
 	IsMergeRequest bool
 }
 
-func (c gitlabIssueContext) LocalID() int64 {
-	return c.localID
-}
-
-func (c gitlabIssueContext) ForeignID() int64 {
-	return c.foreignID
-}
-
 // GetIssues returns issues according start and limit
 //   Note: issue label description and colors are not supported by the go-gitlab library at this time
 func (g *GitlabDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, error) {
@@ -421,24 +411,21 @@ func (g *GitlabDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, er
 		}
 
 		allIssues = append(allIssues, &base.Issue{
-			Title:      issue.Title,
-			Number:     int64(issue.IID),
-			PosterID:   int64(issue.Author.ID),
-			PosterName: issue.Author.Username,
-			Content:    issue.Description,
-			Milestone:  milestone,
-			State:      issue.State,
-			Created:    *issue.CreatedAt,
-			Labels:     labels,
-			Reactions:  reactions,
-			Closed:     issue.ClosedAt,
-			IsLocked:   issue.DiscussionLocked,
-			Updated:    *issue.UpdatedAt,
-			Context: gitlabIssueContext{
-				foreignID:      int64(issue.IID),
-				localID:        int64(issue.IID),
-				IsMergeRequest: false,
-			},
+			Title:        issue.Title,
+			Number:       int64(issue.IID),
+			PosterID:     int64(issue.Author.ID),
+			PosterName:   issue.Author.Username,
+			Content:      issue.Description,
+			Milestone:    milestone,
+			State:        issue.State,
+			Created:      *issue.CreatedAt,
+			Labels:       labels,
+			Reactions:    reactions,
+			Closed:       issue.ClosedAt,
+			IsLocked:     issue.DiscussionLocked,
+			Updated:      *issue.UpdatedAt,
+			ForeignIndex: int64(issue.IID),
+			Context:      gitlabIssueContext{IsMergeRequest: false},
 		})
 
 		// increment issueCount, to be used in GetPullRequests()
@@ -450,10 +437,10 @@ func (g *GitlabDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, er
 
 // GetComments returns comments according issueNumber
 // TODO: figure out how to transfer comment reactions
-func (g *GitlabDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
-	context, ok := opts.Context.(gitlabIssueContext)
+func (g *GitlabDownloader) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
+	context, ok := commentable.GetContext().(gitlabIssueContext)
 	if !ok {
-		return nil, false, fmt.Errorf("unexpected context: %+v", opts.Context)
+		return nil, false, fmt.Errorf("unexpected context: %+v", commentable.GetContext())
 	}
 
 	allComments := make([]*base.Comment, 0, g.maxPerPage)
@@ -465,12 +452,12 @@ func (g *GitlabDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 		var resp *gitlab.Response
 		var err error
 		if !context.IsMergeRequest {
-			comments, resp, err = g.client.Discussions.ListIssueDiscussions(g.repoID, int(context.ForeignID()), &gitlab.ListIssueDiscussionsOptions{
+			comments, resp, err = g.client.Discussions.ListIssueDiscussions(g.repoID, int(commentable.GetForeignIndex()), &gitlab.ListIssueDiscussionsOptions{
 				Page:    page,
 				PerPage: g.maxPerPage,
 			}, nil, gitlab.WithContext(g.ctx))
 		} else {
-			comments, resp, err = g.client.Discussions.ListMergeRequestDiscussions(g.repoID, int(context.ForeignID()), &gitlab.ListMergeRequestDiscussionsOptions{
+			comments, resp, err = g.client.Discussions.ListMergeRequestDiscussions(g.repoID, int(commentable.GetForeignIndex()), &gitlab.ListMergeRequestDiscussionsOptions{
 				Page:    page,
 				PerPage: g.maxPerPage,
 			}, nil, gitlab.WithContext(g.ctx))
@@ -484,7 +471,7 @@ func (g *GitlabDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 			if !comment.IndividualNote {
 				for _, note := range comment.Notes {
 					allComments = append(allComments, &base.Comment{
-						IssueIndex:  context.LocalID(),
+						IssueIndex:  commentable.GetLocalIndex(),
 						Index:       int64(note.ID),
 						PosterID:    int64(note.Author.ID),
 						PosterName:  note.Author.Username,
@@ -496,7 +483,7 @@ func (g *GitlabDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 			} else {
 				c := comment.Notes[0]
 				allComments = append(allComments, &base.Comment{
-					IssueIndex:  context.LocalID(),
+					IssueIndex:  commentable.GetLocalIndex(),
 					Index:       int64(c.ID),
 					PosterID:    int64(c.Author.ID),
 					PosterName:  c.Author.Username,
@@ -619,12 +606,9 @@ func (g *GitlabDownloader) GetPullRequests(page, perPage int) ([]*base.PullReque
 				RepoName:  g.repoName,
 				OwnerName: pr.Author.Username,
 			},
-			PatchURL: pr.WebURL + ".patch",
-			Context: gitlabIssueContext{
-				foreignID:      int64(pr.IID),
-				localID:        newPRNumber,
-				IsMergeRequest: true,
-			},
+			PatchURL:     pr.WebURL + ".patch",
+			ForeignIndex: int64(pr.IID),
+			Context:      gitlabIssueContext{IsMergeRequest: true},
 		})
 	}
 
@@ -632,8 +616,8 @@ func (g *GitlabDownloader) GetPullRequests(page, perPage int) ([]*base.PullReque
 }
 
 // GetReviews returns pull requests review
-func (g *GitlabDownloader) GetReviews(context base.IssueContext) ([]*base.Review, error) {
-	approvals, resp, err := g.client.MergeRequestApprovals.GetConfiguration(g.repoID, int(context.ForeignID()), gitlab.WithContext(g.ctx))
+func (g *GitlabDownloader) GetReviews(reviewable base.Reviewable) ([]*base.Review, error) {
+	approvals, resp, err := g.client.MergeRequestApprovals.GetConfiguration(g.repoID, int(reviewable.GetForeignIndex()), gitlab.WithContext(g.ctx))
 	if err != nil {
 		if resp != nil && resp.StatusCode == 404 {
 			log.Error(fmt.Sprintf("GitlabDownloader: while migrating a error occurred: '%s'", err.Error()))
@@ -654,7 +638,7 @@ func (g *GitlabDownloader) GetReviews(context base.IssueContext) ([]*base.Review
 	reviews := make([]*base.Review, 0, len(approvals.ApprovedBy))
 	for _, user := range approvals.ApprovedBy {
 		reviews = append(reviews, &base.Review{
-			IssueIndex:   context.LocalID(),
+			IssueIndex:   reviewable.GetLocalIndex(),
 			ReviewerID:   int64(user.User.ID),
 			ReviewerName: user.User.Username,
 			CreatedAt:    createdAt,
diff --git a/services/migrations/gitlab_test.go b/services/migrations/gitlab_test.go
index ad61577653c17..52edb2af8fdfc 100644
--- a/services/migrations/gitlab_test.go
+++ b/services/migrations/gitlab_test.go
@@ -214,12 +214,10 @@ func TestGitlabDownloadRepo(t *testing.T) {
 		},
 	}, issues)
 
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: gitlabIssueContext{
-			foreignID:      2,
-			localID:        2,
-			IsMergeRequest: false,
-		},
+	comments, _, err := downloader.GetComments(&base.Issue{
+		Number:       2,
+		ForeignIndex: 2,
+		Context:      gitlabIssueContext{IsMergeRequest: false},
 	})
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
@@ -301,15 +299,12 @@ func TestGitlabDownloadRepo(t *testing.T) {
 			Merged:         false,
 			MergedTime:     nil,
 			MergeCommitSHA: "",
-			Context: gitlabIssueContext{
-				foreignID:      2,
-				localID:        4,
-				IsMergeRequest: true,
-			},
+			ForeignIndex:   2,
+			Context:        gitlabIssueContext{IsMergeRequest: true},
 		},
 	}, prs)
 
-	rvs, err := downloader.GetReviews(base.BasicIssueContext(1))
+	rvs, err := downloader.GetReviews(&base.PullRequest{Number: 1, ForeignIndex: 1})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
@@ -328,7 +323,7 @@ func TestGitlabDownloadRepo(t *testing.T) {
 		},
 	}, rvs)
 
-	rvs, err = downloader.GetReviews(base.BasicIssueContext(2))
+	rvs, err = downloader.GetReviews(&base.PullRequest{Number: 2, ForeignIndex: 2})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
@@ -469,7 +464,8 @@ func TestGitlabGetReviews(t *testing.T) {
 		mock, review := convertTestCase(testCase)
 		mux.HandleFunc(fmt.Sprintf("/api/v4/projects/%d/merge_requests/%d/approvals", testCase.repoID, testCase.prID), mock)
 
-		rvs, err := downloader.GetReviews(base.BasicIssueContext(testCase.prID))
+		id := int64(testCase.prID)
+		rvs, err := downloader.GetReviews(&base.Issue{Number: id, ForeignIndex: id})
 		assert.NoError(t, err)
 		assertReviewsEqual(t, []*base.Review{&review}, rvs)
 	}
diff --git a/services/migrations/gogs.go b/services/migrations/gogs.go
index 0ef39484b7a03..a28033218eac5 100644
--- a/services/migrations/gogs.go
+++ b/services/migrations/gogs.go
@@ -223,10 +223,10 @@ func (g *GogsDownloader) getIssues(page int, state string) ([]*base.Issue, bool,
 }
 
 // GetComments returns comments according issueNumber
-func (g *GogsDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
+func (g *GogsDownloader) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
 	allComments := make([]*base.Comment, 0, 100)
 
-	comments, err := g.client.ListIssueComments(g.repoOwner, g.repoName, opts.Context.ForeignID())
+	comments, err := g.client.ListIssueComments(g.repoOwner, g.repoName, commentable.GetForeignIndex())
 	if err != nil {
 		return nil, false, fmt.Errorf("error while listing repos: %v", err)
 	}
@@ -235,7 +235,7 @@ func (g *GogsDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comme
 			continue
 		}
 		allComments = append(allComments, &base.Comment{
-			IssueIndex:  opts.Context.LocalID(),
+			IssueIndex:  commentable.GetLocalIndex(),
 			Index:       comment.ID,
 			PosterID:    comment.Poster.ID,
 			PosterName:  comment.Poster.Login,
@@ -288,19 +288,19 @@ func convertGogsIssue(issue *gogs.Issue) *base.Issue {
 	}
 
 	return &base.Issue{
-		Title:       issue.Title,
-		Number:      issue.Index,
-		PosterID:    issue.Poster.ID,
-		PosterName:  issue.Poster.Login,
-		PosterEmail: issue.Poster.Email,
-		Content:     issue.Body,
-		Milestone:   milestone,
-		State:       string(issue.State),
-		Created:     issue.Created,
-		Updated:     issue.Updated,
-		Labels:      labels,
-		Closed:      closed,
-		Context:     base.BasicIssueContext(issue.Index),
+		Title:        issue.Title,
+		Number:       issue.Index,
+		PosterID:     issue.Poster.ID,
+		PosterName:   issue.Poster.Login,
+		PosterEmail:  issue.Poster.Email,
+		Content:      issue.Body,
+		Milestone:    milestone,
+		State:        string(issue.State),
+		Created:      issue.Created,
+		Updated:      issue.Updated,
+		Labels:       labels,
+		Closed:       closed,
+		ForeignIndex: issue.Index,
 	}
 }
 
diff --git a/services/migrations/gogs_test.go b/services/migrations/gogs_test.go
index f9d74d3be3ecf..501161b610dad 100644
--- a/services/migrations/gogs_test.go
+++ b/services/migrations/gogs_test.go
@@ -111,9 +111,7 @@ func TestGogsDownloadRepo(t *testing.T) {
 	}, issues)
 
 	// downloader.GetComments()
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: base.BasicIssueContext(1),
-	})
+	comments, _, err := downloader.GetComments(&base.Issue{Number: 1, ForeignIndex: 1})
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
 		{
diff --git a/services/migrations/migrate.go b/services/migrations/migrate.go
index 7bca128ac52f7..b550be4ce75f4 100644
--- a/services/migrations/migrate.go
+++ b/services/migrations/migrate.go
@@ -325,9 +325,7 @@ func migrateRepository(downloader base.Downloader, uploader base.Uploader, opts
 				allComments := make([]*base.Comment, 0, commentBatchSize)
 				for _, issue := range issues {
 					log.Trace("migrating issue %d's comments", issue.Number)
-					comments, _, err := downloader.GetComments(base.GetCommentOptions{
-						Context: issue.Context,
-					})
+					comments, _, err := downloader.GetComments(issue)
 					if err != nil {
 						if !base.IsErrNotSupported(err) {
 							return err
@@ -383,9 +381,7 @@ func migrateRepository(downloader base.Downloader, uploader base.Uploader, opts
 					allComments := make([]*base.Comment, 0, commentBatchSize)
 					for _, pr := range prs {
 						log.Trace("migrating pull request %d's comments", pr.Number)
-						comments, _, err := downloader.GetComments(base.GetCommentOptions{
-							Context: pr.Context,
-						})
+						comments, _, err := downloader.GetComments(pr)
 						if err != nil {
 							if !base.IsErrNotSupported(err) {
 								return err
@@ -412,7 +408,7 @@ func migrateRepository(downloader base.Downloader, uploader base.Uploader, opts
 				// migrate reviews
 				allReviews := make([]*base.Review, 0, reviewBatchSize)
 				for _, pr := range prs {
-					reviews, err := downloader.GetReviews(pr.Context)
+					reviews, err := downloader.GetReviews(pr)
 					if err != nil {
 						if !base.IsErrNotSupported(err) {
 							return err
@@ -446,10 +442,7 @@ func migrateRepository(downloader base.Downloader, uploader base.Uploader, opts
 	if opts.Comments && supportAllComments {
 		log.Trace("migrating comments")
 		for i := 1; ; i++ {
-			comments, isEnd, err := downloader.GetComments(base.GetCommentOptions{
-				Page:     i,
-				PageSize: commentBatchSize,
-			})
+			comments, isEnd, err := downloader.GetAllComments(i, commentBatchSize)
 			if err != nil {
 				return err
 			}
diff --git a/services/migrations/onedev.go b/services/migrations/onedev.go
index d27cbbed4f850..d4b30939ce954 100644
--- a/services/migrations/onedev.go
+++ b/services/migrations/onedev.go
@@ -262,19 +262,9 @@ func (d *OneDevDownloader) GetLabels() ([]*base.Label, error) {
 }
 
 type onedevIssueContext struct {
-	foreignID     int64
-	localID       int64
 	IsPullRequest bool
 }
 
-func (c onedevIssueContext) LocalID() int64 {
-	return c.localID
-}
-
-func (c onedevIssueContext) ForeignID() int64 {
-	return c.foreignID
-}
-
 // GetIssues returns issues
 func (d *OneDevDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, error) {
 	rawIssues := make([]struct {
@@ -346,21 +336,18 @@ func (d *OneDevDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, er
 		}
 		poster := d.tryGetUser(issue.SubmitterID)
 		issues = append(issues, &base.Issue{
-			Title:       issue.Title,
-			Number:      issue.Number,
-			PosterName:  poster.Name,
-			PosterEmail: poster.Email,
-			Content:     issue.Description,
-			Milestone:   d.milestoneMap[milestoneID],
-			State:       state,
-			Created:     issue.SubmitDate,
-			Updated:     issue.SubmitDate,
-			Labels:      []*base.Label{label},
-			Context: onedevIssueContext{
-				foreignID:     issue.ID,
-				localID:       issue.Number,
-				IsPullRequest: false,
-			},
+			Title:        issue.Title,
+			Number:       issue.Number,
+			PosterName:   poster.Name,
+			PosterEmail:  poster.Email,
+			Content:      issue.Description,
+			Milestone:    d.milestoneMap[milestoneID],
+			State:        state,
+			Created:      issue.SubmitDate,
+			Updated:      issue.SubmitDate,
+			Labels:       []*base.Label{label},
+			ForeignIndex: issue.ID,
+			Context:      onedevIssueContext{IsPullRequest: false},
 		})
 
 		if d.maxIssueIndex < issue.Number {
@@ -372,10 +359,10 @@ func (d *OneDevDownloader) GetIssues(page, perPage int) ([]*base.Issue, bool, er
 }
 
 // GetComments returns comments
-func (d *OneDevDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
-	context, ok := opts.Context.(onedevIssueContext)
+func (d *OneDevDownloader) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
+	context, ok := commentable.GetContext().(onedevIssueContext)
 	if !ok {
-		return nil, false, fmt.Errorf("unexpected comment context: %+v", opts.Context)
+		return nil, false, fmt.Errorf("unexpected context: %+v", commentable.GetContext())
 	}
 
 	rawComments := make([]struct {
@@ -387,9 +374,9 @@ func (d *OneDevDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 
 	var endpoint string
 	if context.IsPullRequest {
-		endpoint = fmt.Sprintf("/api/pull-requests/%d/comments", context.ForeignID())
+		endpoint = fmt.Sprintf("/api/pull-requests/%d/comments", commentable.GetForeignIndex())
 	} else {
-		endpoint = fmt.Sprintf("/api/issues/%d/comments", context.ForeignID())
+		endpoint = fmt.Sprintf("/api/issues/%d/comments", commentable.GetForeignIndex())
 	}
 
 	err := d.callAPI(
@@ -408,9 +395,9 @@ func (d *OneDevDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 	}, 0, 100)
 
 	if context.IsPullRequest {
-		endpoint = fmt.Sprintf("/api/pull-requests/%d/changes", context.ForeignID())
+		endpoint = fmt.Sprintf("/api/pull-requests/%d/changes", commentable.GetForeignIndex())
 	} else {
-		endpoint = fmt.Sprintf("/api/issues/%d/changes", context.ForeignID())
+		endpoint = fmt.Sprintf("/api/issues/%d/changes", commentable.GetForeignIndex())
 	}
 
 	err = d.callAPI(
@@ -429,7 +416,7 @@ func (d *OneDevDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 		}
 		poster := d.tryGetUser(comment.UserID)
 		comments = append(comments, &base.Comment{
-			IssueIndex:  context.LocalID(),
+			IssueIndex:  commentable.GetLocalIndex(),
 			Index:       comment.ID,
 			PosterID:    poster.ID,
 			PosterName:  poster.Name,
@@ -454,7 +441,7 @@ func (d *OneDevDownloader) GetComments(opts base.GetCommentOptions) ([]*base.Com
 
 		poster := d.tryGetUser(change.UserID)
 		comments = append(comments, &base.Comment{
-			IssueIndex:  context.LocalID(),
+			IssueIndex:  commentable.GetLocalIndex(),
 			PosterID:    poster.ID,
 			PosterName:  poster.Name,
 			PosterEmail: poster.Email,
@@ -552,11 +539,8 @@ func (d *OneDevDownloader) GetPullRequests(page, perPage int) ([]*base.PullReque
 				SHA:      mergePreview.TargetHeadCommitHash,
 				RepoName: d.repoName,
 			},
-			Context: onedevIssueContext{
-				foreignID:     pr.ID,
-				localID:       number,
-				IsPullRequest: true,
-			},
+			ForeignIndex: pr.ID,
+			Context:      onedevIssueContext{IsPullRequest: true},
 		})
 	}
 
@@ -564,7 +548,7 @@ func (d *OneDevDownloader) GetPullRequests(page, perPage int) ([]*base.PullReque
 }
 
 // GetReviews returns pull requests reviews
-func (d *OneDevDownloader) GetReviews(context base.IssueContext) ([]*base.Review, error) {
+func (d *OneDevDownloader) GetReviews(reviewable base.Reviewable) ([]*base.Review, error) {
 	rawReviews := make([]struct {
 		ID     int64 `json:"id"`
 		UserID int64 `json:"userId"`
@@ -576,7 +560,7 @@ func (d *OneDevDownloader) GetReviews(context base.IssueContext) ([]*base.Review
 	}, 0, 100)
 
 	err := d.callAPI(
-		fmt.Sprintf("/api/pull-requests/%d/reviews", context.ForeignID()),
+		fmt.Sprintf("/api/pull-requests/%d/reviews", reviewable.GetForeignIndex()),
 		nil,
 		&rawReviews,
 	)
@@ -600,7 +584,7 @@ func (d *OneDevDownloader) GetReviews(context base.IssueContext) ([]*base.Review
 
 		poster := d.tryGetUser(review.UserID)
 		reviews = append(reviews, &base.Review{
-			IssueIndex:   context.LocalID(),
+			IssueIndex:   reviewable.GetLocalIndex(),
 			ReviewerID:   poster.ID,
 			ReviewerName: poster.Name,
 			Content:      content,
diff --git a/services/migrations/onedev_test.go b/services/migrations/onedev_test.go
index 59b7cae5feffe..55ae7da1fcc66 100644
--- a/services/migrations/onedev_test.go
+++ b/services/migrations/onedev_test.go
@@ -74,11 +74,8 @@ func TestOneDevDownloadRepo(t *testing.T) {
 					Name: "Improvement",
 				},
 			},
-			Context: onedevIssueContext{
-				foreignID:     398,
-				localID:       4,
-				IsPullRequest: false,
-			},
+			ForeignIndex: 398,
+			Context:      onedevIssueContext{IsPullRequest: false},
 		},
 		{
 			Number:     3,
@@ -94,20 +91,15 @@ func TestOneDevDownloadRepo(t *testing.T) {
 					Name: "New Feature",
 				},
 			},
-			Context: onedevIssueContext{
-				foreignID:     397,
-				localID:       3,
-				IsPullRequest: false,
-			},
+			ForeignIndex: 397,
+			Context:      onedevIssueContext{IsPullRequest: false},
 		},
 	}, issues)
 
-	comments, _, err := downloader.GetComments(base.GetCommentOptions{
-		Context: onedevIssueContext{
-			foreignID:     398,
-			localID:       4,
-			IsPullRequest: false,
-		},
+	comments, _, err := downloader.GetComments(&base.Issue{
+		Number:       4,
+		ForeignIndex: 398,
+		Context:      onedevIssueContext{IsPullRequest: false},
 	})
 	assert.NoError(t, err)
 	assertCommentsEqual(t, []*base.Comment{
@@ -141,18 +133,12 @@ func TestOneDevDownloadRepo(t *testing.T) {
 				SHA:      "f32b0a9dfd09a60f616f29158f772cedd89942d2",
 				RepoName: "go-gitea-test_repo",
 			},
-			Context: onedevIssueContext{
-				foreignID:     186,
-				localID:       5,
-				IsPullRequest: true,
-			},
+			ForeignIndex: 186,
+			Context:      onedevIssueContext{IsPullRequest: true},
 		},
 	}, prs)
 
-	rvs, err := downloader.GetReviews(onedevIssueContext{
-		foreignID: 186,
-		localID:   5,
-	})
+	rvs, err := downloader.GetReviews(&base.PullRequest{Number: 5, ForeignIndex: 186})
 	assert.NoError(t, err)
 	assertReviewsEqual(t, []*base.Review{
 		{
diff --git a/services/migrations/restore.go b/services/migrations/restore.go
index d30d90a6c48f4..8c9654a7e3c2b 100644
--- a/services/migrations/restore.go
+++ b/services/migrations/restore.go
@@ -193,17 +193,13 @@ func (r *RepositoryRestorer) GetIssues(page, perPage int) ([]*base.Issue, bool,
 		}
 		return nil, false, err
 	}
-
-	for _, issue := range issues {
-		issue.Context = base.BasicIssueContext(issue.Number)
-	}
 	return issues, true, nil
 }
 
 // GetComments returns comments according issueNumber
-func (r *RepositoryRestorer) GetComments(opts base.GetCommentOptions) ([]*base.Comment, bool, error) {
+func (r *RepositoryRestorer) GetComments(commentable base.Commentable) ([]*base.Comment, bool, error) {
 	comments := make([]*base.Comment, 0, 10)
-	p := filepath.Join(r.commentDir(), fmt.Sprintf("%d.yml", opts.Context.ForeignID()))
+	p := filepath.Join(r.commentDir(), fmt.Sprintf("%d.yml", commentable.GetForeignIndex()))
 	_, err := os.Stat(p)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -247,15 +243,14 @@ func (r *RepositoryRestorer) GetPullRequests(page, perPage int) ([]*base.PullReq
 	}
 	for _, pr := range pulls {
 		pr.PatchURL = "file://" + filepath.Join(r.baseDir, pr.PatchURL)
-		pr.Context = base.BasicIssueContext(pr.Number)
 	}
 	return pulls, true, nil
 }
 
 // GetReviews returns pull requests review
-func (r *RepositoryRestorer) GetReviews(context base.IssueContext) ([]*base.Review, error) {
+func (r *RepositoryRestorer) GetReviews(reviewable base.Reviewable) ([]*base.Review, error) {
 	reviews := make([]*base.Review, 0, 10)
-	p := filepath.Join(r.reviewDir(), fmt.Sprintf("%d.yml", context.ForeignID()))
+	p := filepath.Join(r.reviewDir(), fmt.Sprintf("%d.yml", reviewable.GetForeignIndex()))
 	_, err := os.Stat(p)
 	if err != nil {
 		if os.IsNotExist(err) {