preserve users if restoring a repository on the same Gitea instance (#18604)

When calling DumpRepository and RestoreRepository on the same Gitea
instance, the users are preserved: all labels, issues etc. belong to
the external user who is, in this particular case, the local user.

Dead code verifying g.gitServiceType.Name() == "" (i.e. plain git) is
removed. The function is never called because the plain git downloader
does not migrate anything that is associated to a user, by definition.

Errors returned by GetUserIDByExternalUserID are no longer ignored.

The userMap is used when the external user is not kown, which is the
most common case. It was only used when the external user exists
which happens less often and, as a result, every occurence of an
unknown external user required a SQL query.

Signed-off-by: Loïc Dachary <loic@dachary.org>

Co-authored-by: Loïc Dachary <loic@dachary.org>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

2 files changed, 111 insertions, 26 deletions

diff --git a/services/migrations/gitea_uploader.go b/services/migrations/gitea_uploader.go
index da085c0d8d..8f0505afc5 100644
--- a/services/migrations/gitea_uploader.go
+++ b/services/migrations/gitea_uploader.go
@@ -46,6 +46,7 @@ type GiteaLocalUploader struct {
 	issues         map[int64]*models.Issue
 	gitRepo        *git.Repository
 	prHeadCache    map[string]struct{}
+	sameApp        bool
 	userMap        map[int64]int64 // external user id mapping to user id
 	prCache        map[int64]*models.PullRequest
 	gitServiceType structs.GitServiceType
@@ -128,6 +129,7 @@ func (g *GiteaLocalUploader) CreateRepo(repo *base.Repository, opts base.Migrate
 		MirrorInterval: opts.MirrorInterval,
 	}, NewMigrationHTTPTransport())
 
+	g.sameApp = strings.HasPrefix(repo.OriginalURL, setting.AppURL)
 	g.repo = r
 	if err != nil {
 		return err
@@ -256,7 +258,7 @@ func (g *GiteaLocalUploader) CreateReleases(releases ...*base.Release) error {
 			CreatedUnix:  timeutil.TimeStamp(release.Created.Unix()),
 		}
 
-		if err := g.remapExternalUser(release, &rel); err != nil {
+		if err := g.remapUser(release, &rel); err != nil {
 			return err
 		}
 
@@ -373,7 +375,7 @@ func (g *GiteaLocalUploader) CreateIssues(issues ...*base.Issue) error {
 			UpdatedUnix: timeutil.TimeStamp(issue.Updated.Unix()),
 		}
 
-		if err := g.remapExternalUser(issue, &is); err != nil {
+		if err := g.remapUser(issue, &is); err != nil {
 			return err
 		}
 
@@ -386,7 +388,7 @@ func (g *GiteaLocalUploader) CreateIssues(issues ...*base.Issue) error {
 				Type:        reaction.Content,
 				CreatedUnix: timeutil.TimeStampNow(),
 			}
-			if err := g.remapExternalUser(reaction, &res); err != nil {
+			if err := g.remapUser(reaction, &res); err != nil {
 				return err
 			}
 			is.Reactions = append(is.Reactions, &res)
@@ -437,7 +439,7 @@ func (g *GiteaLocalUploader) CreateComments(comments ...*base.Comment) error {
 			UpdatedUnix: timeutil.TimeStamp(comment.Updated.Unix()),
 		}
 
-		if err := g.remapExternalUser(comment, &cm); err != nil {
+		if err := g.remapUser(comment, &cm); err != nil {
 			return err
 		}
 
@@ -447,7 +449,7 @@ func (g *GiteaLocalUploader) CreateComments(comments ...*base.Comment) error {
 				Type:        reaction.Content,
 				CreatedUnix: timeutil.TimeStampNow(),
 			}
-			if err := g.remapExternalUser(reaction, &res); err != nil {
+			if err := g.remapUser(reaction, &res); err != nil {
 				return err
 			}
 			cm.Reactions = append(cm.Reactions, &res)
@@ -471,7 +473,7 @@ func (g *GiteaLocalUploader) CreatePullRequests(prs ...*base.PullRequest) error
 			return err
 		}
 
-		if err := g.remapExternalUser(pr, gpr.Issue); err != nil {
+		if err := g.remapUser(pr, gpr.Issue); err != nil {
 			return err
 		}
 
@@ -626,7 +628,7 @@ func (g *GiteaLocalUploader) newPullRequest(pr *base.PullRequest) (*models.PullR
 		UpdatedUnix: timeutil.TimeStamp(pr.Updated.Unix()),
 	}
 
-	if err := g.remapExternalUser(pr, &issue); err != nil {
+	if err := g.remapUser(pr, &issue); err != nil {
 		return nil, err
 	}
 
@@ -636,7 +638,7 @@ func (g *GiteaLocalUploader) newPullRequest(pr *base.PullRequest) (*models.PullR
 			Type:        reaction.Content,
 			CreatedUnix: timeutil.TimeStampNow(),
 		}
-		if err := g.remapExternalUser(reaction, &res); err != nil {
+		if err := g.remapUser(reaction, &res); err != nil {
 			return nil, err
 		}
 		issue.Reactions = append(issue.Reactions, &res)
@@ -710,7 +712,7 @@ func (g *GiteaLocalUploader) CreateReviews(reviews ...*base.Review) error {
 			UpdatedUnix: timeutil.TimeStamp(review.CreatedAt.Unix()),
 		}
 
-		if err := g.remapExternalUser(review, &cm); err != nil {
+		if err := g.remapUser(review, &cm); err != nil {
 			return err
 		}
 
@@ -773,7 +775,7 @@ func (g *GiteaLocalUploader) CreateReviews(reviews ...*base.Review) error {
 				UpdatedUnix: timeutil.TimeStamp(comment.UpdatedAt.Unix()),
 			}
 
-			if err := g.remapExternalUser(review, &c); err != nil {
+			if err := g.remapUser(review, &c); err != nil {
 				return err
 			}
 
@@ -816,23 +818,52 @@ func (g *GiteaLocalUploader) Finish() error {
 	return repo_model.UpdateRepositoryCols(g.repo, "status")
 }
 
-func (g *GiteaLocalUploader) remapExternalUser(source user_model.ExternalUserMigrated, target user_model.ExternalUserRemappable) (err error) {
+func (g *GiteaLocalUploader) remapUser(source user_model.ExternalUserMigrated, target user_model.ExternalUserRemappable) error {
+	var userid int64
+	var err error
+	if g.sameApp {
+		userid, err = g.remapLocalUser(source, target)
+	} else {
+		userid, err = g.remapExternalUser(source, target)
+	}
+
+	if err != nil {
+		return err
+	}
+
+	if userid > 0 {
+		return target.RemapExternalUser("", 0, userid)
+	}
+	return target.RemapExternalUser(source.GetExternalName(), source.GetExternalID(), g.doer.ID)
+}
+
+func (g *GiteaLocalUploader) remapLocalUser(source user_model.ExternalUserMigrated, target user_model.ExternalUserRemappable) (int64, error) {
 	userid, ok := g.userMap[source.GetExternalID()]
-	tp := g.gitServiceType.Name()
-	if !ok && tp != "" {
-		userid, err = user_model.GetUserIDByExternalUserID(tp, fmt.Sprintf("%d", source.GetExternalID()))
+	if !ok {
+		name, err := user_model.GetUserNameByID(g.ctx, source.GetExternalID())
 		if err != nil {
-			log.Error("GetUserIDByExternalUserID: %v", err)
+			return 0, err
 		}
-		if userid > 0 {
-			g.userMap[source.GetExternalID()] = userid
+		// let's not reuse an ID when the user was deleted or has a different user name
+		if name != source.GetExternalName() {
+			userid = 0
+		} else {
+			userid = source.GetExternalID()
 		}
+		g.userMap[source.GetExternalID()] = userid
 	}
+	return userid, nil
+}
 
-	if userid > 0 {
-		err = target.RemapExternalUser("", 0, userid)
-	} else {
-		err = target.RemapExternalUser(source.GetExternalName(), source.GetExternalID(), g.doer.ID)
+func (g *GiteaLocalUploader) remapExternalUser(source user_model.ExternalUserMigrated, target user_model.ExternalUserRemappable) (userid int64, err error) {
+	userid, ok := g.userMap[source.GetExternalID()]
+	if !ok {
+		userid, err = user_model.GetUserIDByExternalUserID(g.gitServiceType.Name(), fmt.Sprintf("%d", source.GetExternalID()))
+		if err != nil {
+			log.Error("GetUserIDByExternalUserID: %v", err)
+			return 0, err
+		}
+		g.userMap[source.GetExternalID()] = userid
 	}
-	return
+	return userid, nil
 }
diff --git a/services/migrations/gitea_uploader_test.go b/services/migrations/gitea_uploader_test.go
index 7552245d74..0a35b5a632 100644
--- a/services/migrations/gitea_uploader_test.go
+++ b/services/migrations/gitea_uploader_test.go
@@ -117,6 +117,56 @@ func TestGiteaUploadRepo(t *testing.T) {
 	assert.Len(t, pulls[0].Issue.Comments, 2)
 }
 
+func TestGiteaUploadRemapLocalUser(t *testing.T) {
+	unittest.PrepareTestEnv(t)
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1}).(*user_model.User)
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2}).(*user_model.User)
+
+	repoName := "migrated"
+	uploader := NewGiteaLocalUploader(context.Background(), doer, doer.Name, repoName)
+	// call remapLocalUser
+	uploader.sameApp = true
+
+	externalID := int64(1234567)
+	externalName := "username"
+	source := base.Release{
+		PublisherID:   externalID,
+		PublisherName: externalName,
+	}
+
+	//
+	// The externalID does not match any existing user, everything
+	// belongs to the doer
+	//
+	target := models.Release{}
+	uploader.userMap = make(map[int64]int64)
+	err := uploader.remapUser(&source, &target)
+	assert.NoError(t, err)
+	assert.EqualValues(t, doer.ID, target.GetUserID())
+
+	//
+	// The externalID matches a known user but the name does not match,
+	// everything belongs to the doer
+	//
+	source.PublisherID = user.ID
+	target = models.Release{}
+	uploader.userMap = make(map[int64]int64)
+	err = uploader.remapUser(&source, &target)
+	assert.NoError(t, err)
+	assert.EqualValues(t, doer.ID, target.GetUserID())
+
+	//
+	// The externalID and externalName match an existing user, everything
+	// belongs to the existing user
+	//
+	source.PublisherName = user.Name
+	target = models.Release{}
+	uploader.userMap = make(map[int64]int64)
+	err = uploader.remapUser(&source, &target)
+	assert.NoError(t, err)
+	assert.EqualValues(t, user.ID, target.GetUserID())
+}
+
 func TestGiteaUploadRemapExternalUser(t *testing.T) {
 	unittest.PrepareTestEnv(t)
 	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1}).(*user_model.User)
@@ -124,9 +174,11 @@ func TestGiteaUploadRemapExternalUser(t *testing.T) {
 	repoName := "migrated"
 	uploader := NewGiteaLocalUploader(context.Background(), doer, doer.Name, repoName)
 	uploader.gitServiceType = structs.GiteaService
+	// call remapExternalUser
+	uploader.sameApp = false
 
 	externalID := int64(1234567)
-	externalName := "url.or.something"
+	externalName := "username"
 	source := base.Release{
 		PublisherID:   externalID,
 		PublisherName: externalName,
@@ -136,8 +188,9 @@ func TestGiteaUploadRemapExternalUser(t *testing.T) {
 	// When there is no user linked to the external ID, the migrated data is authored
 	// by the doer
 	//
+	uploader.userMap = make(map[int64]int64)
 	target := models.Release{}
-	err := uploader.remapExternalUser(&source, &target)
+	err := uploader.remapUser(&source, &target)
 	assert.NoError(t, err)
 	assert.EqualValues(t, doer.ID, target.GetUserID())
 
@@ -158,8 +211,9 @@ func TestGiteaUploadRemapExternalUser(t *testing.T) {
 	// When a user is linked to the external ID, it becomes the author of
 	// the migrated data
 	//
+	uploader.userMap = make(map[int64]int64)
 	target = models.Release{}
-	err = uploader.remapExternalUser(&source, &target)
+	err = uploader.remapUser(&source, &target)
 	assert.NoError(t, err)
-	assert.EqualValues(t, target.GetUserID(), linkedUser.ID)
+	assert.EqualValues(t, linkedUser.ID, target.GetUserID())
 }