diff --git a/models/perm/access_mode.go b/models/perm/access_mode.go
index 0364191e2e..6baeb5531a 100644
--- a/models/perm/access_mode.go
+++ b/models/perm/access_mode.go
@@ -60,3 +60,6 @@ func ParseAccessMode(permission string, allowed ...AccessMode) AccessMode {
 	}
 	return util.Iif(slices.Contains(allowed, m), m, AccessModeNone)
 }
+
+// ErrInvalidAccessMode is returned when an invalid access mode is used
+var ErrInvalidAccessMode = util.NewInvalidArgumentErrorf("Invalid access mode")
diff --git a/modules/repository/collaborator.go b/modules/repository/collaborator.go
deleted file mode 100644
index f71c58fbdf..0000000000
--- a/modules/repository/collaborator.go
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2022 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package repository
-
-import (
-	"context"
-
-	"code.gitea.io/gitea/models/db"
-	"code.gitea.io/gitea/models/perm"
-	access_model "code.gitea.io/gitea/models/perm/access"
-	repo_model "code.gitea.io/gitea/models/repo"
-	user_model "code.gitea.io/gitea/models/user"
-
-	"xorm.io/builder"
-)
-
-func AddCollaborator(ctx context.Context, repo *repo_model.Repository, u *user_model.User) error {
-	if err := repo.LoadOwner(ctx); err != nil {
-		return err
-	}
-
-	if user_model.IsUserBlockedBy(ctx, u, repo.OwnerID) || user_model.IsUserBlockedBy(ctx, repo.Owner, u.ID) {
-		return user_model.ErrBlockedUser
-	}
-
-	return db.WithTx(ctx, func(ctx context.Context) error {
-		has, err := db.Exist[repo_model.Collaboration](ctx, builder.Eq{
-			"repo_id": repo.ID,
-			"user_id": u.ID,
-		})
-		if err != nil {
-			return err
-		} else if has {
-			return nil
-		}
-
-		if err = db.Insert(ctx, &repo_model.Collaboration{
-			RepoID: repo.ID,
-			UserID: u.ID,
-			Mode:   perm.AccessModeWrite,
-		}); err != nil {
-			return err
-		}
-
-		return access_model.RecalculateUserAccess(ctx, repo, u.ID)
-	})
-}
diff --git a/modules/repository/collaborator_test.go b/modules/repository/collaborator_test.go
deleted file mode 100644
index 622f6abce4..0000000000
--- a/modules/repository/collaborator_test.go
+++ /dev/null
@@ -1,280 +0,0 @@
-// Copyright 2019 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package repository
-
-import (
-	"testing"
-
-	"code.gitea.io/gitea/models/db"
-	"code.gitea.io/gitea/models/organization"
-	perm_model "code.gitea.io/gitea/models/perm"
-	access_model "code.gitea.io/gitea/models/perm/access"
-	repo_model "code.gitea.io/gitea/models/repo"
-	"code.gitea.io/gitea/models/unit"
-	"code.gitea.io/gitea/models/unittest"
-	user_model "code.gitea.io/gitea/models/user"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestRepository_AddCollaborator(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	testSuccess := func(repoID, userID int64) {
-		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repoID})
-		assert.NoError(t, repo.LoadOwner(db.DefaultContext))
-		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: userID})
-		assert.NoError(t, AddCollaborator(db.DefaultContext, repo, user))
-		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
-	}
-	testSuccess(1, 4)
-	testSuccess(1, 4)
-	testSuccess(3, 4)
-}
-
-func TestRepoPermissionPublicNonOrgRepo(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	// public non-organization repo
-	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
-	assert.NoError(t, repo.LoadUnits(db.DefaultContext))
-
-	// plain user
-	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
-	perm, err := access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// change to collaborator
-	assert.NoError(t, AddCollaborator(db.DefaultContext, repo, user))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// collaborator
-	collaborator := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 4})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, collaborator)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// owner
-	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, owner)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// admin
-	admin := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, admin)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-}
-
-func TestRepoPermissionPrivateNonOrgRepo(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	// private non-organization repo
-	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2})
-	assert.NoError(t, repo.LoadUnits(db.DefaultContext))
-
-	// plain user
-	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 4})
-	perm, err := access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.False(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// change to collaborator to default write access
-	assert.NoError(t, AddCollaborator(db.DefaultContext, repo, user))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	assert.NoError(t, repo_model.ChangeCollaborationAccessMode(db.DefaultContext, repo, user.ID, perm_model.AccessModeRead))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// owner
-	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, owner)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// admin
-	admin := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, admin)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-}
-
-func TestRepoPermissionPublicOrgRepo(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	// public organization repo
-	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 32})
-	assert.NoError(t, repo.LoadUnits(db.DefaultContext))
-
-	// plain user
-	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
-	perm, err := access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// change to collaborator to default write access
-	assert.NoError(t, AddCollaborator(db.DefaultContext, repo, user))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	assert.NoError(t, repo_model.ChangeCollaborationAccessMode(db.DefaultContext, repo, user.ID, perm_model.AccessModeRead))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// org member team owner
-	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, owner)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// org member team tester
-	member := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 15})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, member)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-	}
-	assert.True(t, perm.CanWrite(unit.TypeIssues))
-	assert.False(t, perm.CanWrite(unit.TypeCode))
-
-	// admin
-	admin := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, admin)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-}
-
-func TestRepoPermissionPrivateOrgRepo(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	// private organization repo
-	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 24})
-	assert.NoError(t, repo.LoadUnits(db.DefaultContext))
-
-	// plain user
-	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
-	perm, err := access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.False(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// change to collaborator to default write access
-	assert.NoError(t, AddCollaborator(db.DefaultContext, repo, user))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	assert.NoError(t, repo_model.ChangeCollaborationAccessMode(db.DefaultContext, repo, user.ID, perm_model.AccessModeRead))
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, user)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.False(t, perm.CanWrite(unit.Type))
-	}
-
-	// org member team owner
-	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 15})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, owner)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// update team information and then check permission
-	team := unittest.AssertExistsAndLoadBean(t, &organization.Team{ID: 5})
-	err = organization.UpdateTeamUnits(db.DefaultContext, team, nil)
-	assert.NoError(t, err)
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, owner)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-
-	// org member team tester
-	tester := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, tester)
-	assert.NoError(t, err)
-	assert.True(t, perm.CanWrite(unit.TypeIssues))
-	assert.False(t, perm.CanWrite(unit.TypeCode))
-	assert.False(t, perm.CanRead(unit.TypeCode))
-
-	// org member team reviewer
-	reviewer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 20})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, reviewer)
-	assert.NoError(t, err)
-	assert.False(t, perm.CanRead(unit.TypeIssues))
-	assert.False(t, perm.CanWrite(unit.TypeCode))
-	assert.True(t, perm.CanRead(unit.TypeCode))
-
-	// admin
-	admin := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
-	perm, err = access_model.GetUserRepoPermission(db.DefaultContext, repo, admin)
-	assert.NoError(t, err)
-	for _, unit := range repo.Units {
-		assert.True(t, perm.CanRead(unit.Type))
-		assert.True(t, perm.CanWrite(unit.Type))
-	}
-}
diff --git a/modules/repository/create.go b/modules/repository/create.go
index 4f18b9b3fa..b4f7033bd7 100644
--- a/modules/repository/create.go
+++ b/modules/repository/create.go
@@ -11,160 +11,17 @@ import (
 	"path/filepath"
 	"strings"
 
-	"code.gitea.io/gitea/models"
 	activities_model "code.gitea.io/gitea/models/activities"
 	"code.gitea.io/gitea/models/db"
 	git_model "code.gitea.io/gitea/models/git"
-	"code.gitea.io/gitea/models/organization"
-	"code.gitea.io/gitea/models/perm"
 	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
-	"code.gitea.io/gitea/models/unit"
-	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/models/webhook"
 	issue_indexer "code.gitea.io/gitea/modules/indexer/issues"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/util"
 )
 
-// CreateRepositoryByExample creates a repository for the user/organization.
-func CreateRepositoryByExample(ctx context.Context, doer, u *user_model.User, repo *repo_model.Repository, overwriteOrAdopt, isFork bool) (err error) {
-	if err = repo_model.IsUsableRepoName(repo.Name); err != nil {
-		return err
-	}
-
-	has, err := repo_model.IsRepositoryModelExist(ctx, u, repo.Name)
-	if err != nil {
-		return fmt.Errorf("IsRepositoryExist: %w", err)
-	} else if has {
-		return repo_model.ErrRepoAlreadyExist{
-			Uname: u.Name,
-			Name:  repo.Name,
-		}
-	}
-
-	repoPath := repo_model.RepoPath(u.Name, repo.Name)
-	isExist, err := util.IsExist(repoPath)
-	if err != nil {
-		log.Error("Unable to check if %s exists. Error: %v", repoPath, err)
-		return err
-	}
-	if !overwriteOrAdopt && isExist {
-		log.Error("Files already exist in %s and we are not going to adopt or delete.", repoPath)
-		return repo_model.ErrRepoFilesAlreadyExist{
-			Uname: u.Name,
-			Name:  repo.Name,
-		}
-	}
-
-	if err = db.Insert(ctx, repo); err != nil {
-		return err
-	}
-	if err = repo_model.DeleteRedirect(ctx, u.ID, repo.Name); err != nil {
-		return err
-	}
-
-	// insert units for repo
-	defaultUnits := unit.DefaultRepoUnits
-	if isFork {
-		defaultUnits = unit.DefaultForkRepoUnits
-	}
-	units := make([]repo_model.RepoUnit, 0, len(defaultUnits))
-	for _, tp := range defaultUnits {
-		if tp == unit.TypeIssues {
-			units = append(units, repo_model.RepoUnit{
-				RepoID: repo.ID,
-				Type:   tp,
-				Config: &repo_model.IssuesConfig{
-					EnableTimetracker:                setting.Service.DefaultEnableTimetracking,
-					AllowOnlyContributorsToTrackTime: setting.Service.DefaultAllowOnlyContributorsToTrackTime,
-					EnableDependencies:               setting.Service.DefaultEnableDependencies,
-				},
-			})
-		} else if tp == unit.TypePullRequests {
-			units = append(units, repo_model.RepoUnit{
-				RepoID: repo.ID,
-				Type:   tp,
-				Config: &repo_model.PullRequestsConfig{
-					AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true, AllowFastForwardOnly: true,
-					DefaultMergeStyle: repo_model.MergeStyle(setting.Repository.PullRequest.DefaultMergeStyle),
-					AllowRebaseUpdate: true,
-				},
-			})
-		} else if tp == unit.TypeProjects {
-			units = append(units, repo_model.RepoUnit{
-				RepoID: repo.ID,
-				Type:   tp,
-				Config: &repo_model.ProjectsConfig{ProjectsMode: repo_model.ProjectsModeAll},
-			})
-		} else {
-			units = append(units, repo_model.RepoUnit{
-				RepoID: repo.ID,
-				Type:   tp,
-			})
-		}
-	}
-
-	if err = db.Insert(ctx, units); err != nil {
-		return err
-	}
-
-	// Remember visibility preference.
-	u.LastRepoVisibility = repo.IsPrivate
-	if err = user_model.UpdateUserCols(ctx, u, "last_repo_visibility"); err != nil {
-		return fmt.Errorf("UpdateUserCols: %w", err)
-	}
-
-	if err = user_model.IncrUserRepoNum(ctx, u.ID); err != nil {
-		return fmt.Errorf("IncrUserRepoNum: %w", err)
-	}
-	u.NumRepos++
-
-	// Give access to all members in teams with access to all repositories.
-	if u.IsOrganization() {
-		teams, err := organization.FindOrgTeams(ctx, u.ID)
-		if err != nil {
-			return fmt.Errorf("FindOrgTeams: %w", err)
-		}
-		for _, t := range teams {
-			if t.IncludesAllRepositories {
-				if err := models.AddRepository(ctx, t, repo); err != nil {
-					return fmt.Errorf("AddRepository: %w", err)
-				}
-			}
-		}
-
-		if isAdmin, err := access_model.IsUserRepoAdmin(ctx, repo, doer); err != nil {
-			return fmt.Errorf("IsUserRepoAdmin: %w", err)
-		} else if !isAdmin {
-			// Make creator repo admin if it wasn't assigned automatically
-			if err = AddCollaborator(ctx, repo, doer); err != nil {
-				return fmt.Errorf("AddCollaborator: %w", err)
-			}
-			if err = repo_model.ChangeCollaborationAccessMode(ctx, repo, doer.ID, perm.AccessModeAdmin); err != nil {
-				return fmt.Errorf("ChangeCollaborationAccessModeCtx: %w", err)
-			}
-		}
-	} else if err = access_model.RecalculateAccesses(ctx, repo); err != nil {
-		// Organization automatically called this in AddRepository method.
-		return fmt.Errorf("RecalculateAccesses: %w", err)
-	}
-
-	if setting.Service.AutoWatchNewRepos {
-		if err = repo_model.WatchRepo(ctx, doer, repo, true); err != nil {
-			return fmt.Errorf("WatchRepo: %w", err)
-		}
-	}
-
-	if err = webhook.CopyDefaultWebhooksToRepo(ctx, repo.ID); err != nil {
-		return fmt.Errorf("CopyDefaultWebhooksToRepo: %w", err)
-	}
-
-	return nil
-}
-
 const notRegularFileMode = os.ModeSymlink | os.ModeNamedPipe | os.ModeSocket | os.ModeDevice | os.ModeCharDevice | os.ModeIrregular
 
 // getDirectorySize returns the disk consumption for a given path
diff --git a/modules/repository/main_test.go b/modules/repository/main_test.go
index f81dfcdafb..799e8c17c3 100644
--- a/modules/repository/main_test.go
+++ b/modules/repository/main_test.go
@@ -8,6 +8,7 @@ import (
 
 	"code.gitea.io/gitea/models/unittest"
 
+	_ "code.gitea.io/gitea/models"
 	_ "code.gitea.io/gitea/models/actions"
 )
 
diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index bfc601c835..23f466873b 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -1172,7 +1172,7 @@ func Routes() *web.Router {
 					m.Get("", reqAnyRepoReader(), repo.ListCollaborators)
 					m.Group("/{collaborator}", func() {
 						m.Combo("").Get(reqAnyRepoReader(), repo.IsCollaborator).
-							Put(reqAdmin(), bind(api.AddCollaboratorOption{}), repo.AddCollaborator).
+							Put(reqAdmin(), bind(api.AddCollaboratorOption{}), repo.AddOrUpdateCollaborator).
 							Delete(reqAdmin(), repo.DeleteCollaborator)
 						m.Get("/permission", repo.GetRepoPermissions)
 					})
diff --git a/routers/api/v1/repo/collaborators.go b/routers/api/v1/repo/collaborators.go
index 39c9ba527d..ea9d8b0f37 100644
--- a/routers/api/v1/repo/collaborators.go
+++ b/routers/api/v1/repo/collaborators.go
@@ -12,7 +12,6 @@ import (
 	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
-	repo_module "code.gitea.io/gitea/modules/repository"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/api/v1/utils"
@@ -123,11 +122,11 @@ func IsCollaborator(ctx *context.APIContext) {
 	}
 }
 
-// AddCollaborator add a collaborator to a repository
-func AddCollaborator(ctx *context.APIContext) {
+// AddOrUpdateCollaborator add or update a collaborator to a repository
+func AddOrUpdateCollaborator(ctx *context.APIContext) {
 	// swagger:operation PUT /repos/{owner}/{repo}/collaborators/{collaborator} repository repoAddCollaborator
 	// ---
-	// summary: Add a collaborator to a repository
+	// summary: Add or Update a collaborator to a repository
 	// produces:
 	// - application/json
 	// parameters:
@@ -177,20 +176,18 @@ func AddCollaborator(ctx *context.APIContext) {
 		return
 	}
 
-	if err := repo_module.AddCollaborator(ctx, ctx.Repo.Repository, collaborator); err != nil {
-		if errors.Is(err, user_model.ErrBlockedUser) {
-			ctx.Error(http.StatusForbidden, "AddCollaborator", err)
-		} else {
-			ctx.Error(http.StatusInternalServerError, "AddCollaborator", err)
-		}
-		return
+	p := perm.AccessModeWrite
+	if form.Permission != nil {
+		p = perm.ParseAccessMode(*form.Permission)
 	}
 
-	if form.Permission != nil {
-		if err := repo_model.ChangeCollaborationAccessMode(ctx, ctx.Repo.Repository, collaborator.ID, perm.ParseAccessMode(*form.Permission)); err != nil {
-			ctx.Error(http.StatusInternalServerError, "ChangeCollaborationAccessMode", err)
-			return
+	if err := repo_service.AddOrUpdateCollaborator(ctx, ctx.Repo.Repository, collaborator, p); err != nil {
+		if errors.Is(err, user_model.ErrBlockedUser) {
+			ctx.Error(http.StatusForbidden, "AddOrUpdateCollaborator", err)
+		} else {
+			ctx.Error(http.StatusInternalServerError, "AddOrUpdateCollaborator", err)
 		}
+		return
 	}
 
 	ctx.Status(http.StatusNoContent)
diff --git a/routers/web/repo/setting/collaboration.go b/routers/web/repo/setting/collaboration.go
index 31f9f76d0f..18ecff8250 100644
--- a/routers/web/repo/setting/collaboration.go
+++ b/routers/web/repo/setting/collaboration.go
@@ -14,7 +14,6 @@ import (
 	unit_model "code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/log"
-	repo_module "code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/services/context"
 	"code.gitea.io/gitea/services/mailer"
@@ -100,12 +99,12 @@ func CollaborationPost(ctx *context.Context) {
 		}
 	}
 
-	if err = repo_module.AddCollaborator(ctx, ctx.Repo.Repository, u); err != nil {
+	if err = repo_service.AddOrUpdateCollaborator(ctx, ctx.Repo.Repository, u, perm.AccessModeWrite); err != nil {
 		if errors.Is(err, user_model.ErrBlockedUser) {
 			ctx.Flash.Error(ctx.Tr("repo.settings.add_collaborator.blocked_user"))
 			ctx.Redirect(ctx.Repo.RepoLink + "/settings/collaboration")
 		} else {
-			ctx.ServerError("AddCollaborator", err)
+			ctx.ServerError("AddOrUpdateCollaborator", err)
 		}
 		return
 	}
diff --git a/services/feed/action_test.go b/services/feed/action_test.go
index e1b071d8f6..60cf7fbb49 100644
--- a/services/feed/action_test.go
+++ b/services/feed/action_test.go
@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
 
+	_ "code.gitea.io/gitea/models"
 	_ "code.gitea.io/gitea/models/actions"
 
 	"github.com/stretchr/testify/assert"
diff --git a/services/issue/main_test.go b/services/issue/main_test.go
index 5dac54183b..819c5d98c3 100644
--- a/services/issue/main_test.go
+++ b/services/issue/main_test.go
@@ -8,6 +8,7 @@ import (
 
 	"code.gitea.io/gitea/models/unittest"
 
+	_ "code.gitea.io/gitea/models"
 	_ "code.gitea.io/gitea/models/actions"
 )
 
diff --git a/services/mailer/main_test.go b/services/mailer/main_test.go
index f803c736ca..5591bea02b 100644
--- a/services/mailer/main_test.go
+++ b/services/mailer/main_test.go
@@ -8,6 +8,7 @@ import (
 
 	"code.gitea.io/gitea/models/unittest"
 
+	_ "code.gitea.io/gitea/models"
 	_ "code.gitea.io/gitea/models/actions"
 )
 
diff --git a/services/repository/adopt.go b/services/repository/adopt.go
index 3d6fe71a09..615f4d482c 100644
--- a/services/repository/adopt.go
+++ b/services/repository/adopt.go
@@ -66,7 +66,7 @@ func AdoptRepository(ctx context.Context, doer, u *user_model.User, opts CreateR
 			}
 		}
 
-		if err := repo_module.CreateRepositoryByExample(ctx, doer, u, repo, true, false); err != nil {
+		if err := CreateRepositoryByExample(ctx, doer, u, repo, true, false); err != nil {
 			return err
 		}
 
diff --git a/services/repository/collaboration.go b/services/repository/collaboration.go
index 4a43ae2a28..abe0489fc5 100644
--- a/services/repository/collaboration.go
+++ b/services/repository/collaboration.go
@@ -9,11 +9,60 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/perm"
 	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
+
+	"xorm.io/builder"
 )
 
+func AddOrUpdateCollaborator(ctx context.Context, repo *repo_model.Repository, u *user_model.User, mode perm.AccessMode) error {
+	// only allow valid access modes, read, write and admin
+	if mode < perm.AccessModeRead || mode > perm.AccessModeAdmin {
+		return perm.ErrInvalidAccessMode
+	}
+
+	if err := repo.LoadOwner(ctx); err != nil {
+		return err
+	}
+
+	if user_model.IsUserBlockedBy(ctx, u, repo.OwnerID) || user_model.IsUserBlockedBy(ctx, repo.Owner, u.ID) {
+		return user_model.ErrBlockedUser
+	}
+
+	return db.WithTx(ctx, func(ctx context.Context) error {
+		collaboration, has, err := db.Get[repo_model.Collaboration](ctx, builder.Eq{
+			"repo_id": repo.ID,
+			"user_id": u.ID,
+		})
+		if err != nil {
+			return err
+		} else if has {
+			if collaboration.Mode == mode {
+				return nil
+			}
+			if _, err = db.GetEngine(ctx).
+				Where("repo_id=?", repo.ID).
+				And("user_id=?", u.ID).
+				Cols("mode").
+				Update(&repo_model.Collaboration{
+					Mode: mode,
+				}); err != nil {
+				return err
+			}
+		} else if err = db.Insert(ctx, &repo_model.Collaboration{
+			RepoID: repo.ID,
+			UserID: u.ID,
+			Mode:   mode,
+		}); err != nil {
+			return err
+		}
+
+		return access_model.RecalculateUserAccess(ctx, repo, u.ID)
+	})
+}
+
 // DeleteCollaboration removes collaboration relation between the user and repository.
 func DeleteCollaboration(ctx context.Context, repo *repo_model.Repository, collaborator *user_model.User) (err error) {
 	collaboration := &repo_model.Collaboration{
diff --git a/services/repository/collaboration_test.go b/services/repository/collaboration_test.go
index a2eb06b81a..2b9a5d0b8b 100644
--- a/services/repository/collaboration_test.go
+++ b/services/repository/collaboration_test.go
@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/perm"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
@@ -14,6 +15,21 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestRepository_AddCollaborator(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	testSuccess := func(repoID, userID int64) {
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repoID})
+		assert.NoError(t, repo.LoadOwner(db.DefaultContext))
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: userID})
+		assert.NoError(t, AddOrUpdateCollaborator(db.DefaultContext, repo, user, perm.AccessModeWrite))
+		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
+	}
+	testSuccess(1, 4)
+	testSuccess(1, 4)
+	testSuccess(3, 4)
+}
+
 func TestRepository_DeleteCollaboration(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
diff --git a/services/repository/create.go b/services/repository/create.go
index 282b2d3e58..261ac7fccc 100644
--- a/services/repository/create.go
+++ b/services/repository/create.go
@@ -12,9 +12,15 @@ import (
 	"strings"
 	"time"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/organization"
+	"code.gitea.io/gitea/models/perm"
+	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/models/webhook"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/log"
@@ -243,7 +249,7 @@ func CreateRepositoryDirectly(ctx context.Context, doer, u *user_model.User, opt
 	var rollbackRepo *repo_model.Repository
 
 	if err := db.WithTx(ctx, func(ctx context.Context) error {
-		if err := repo_module.CreateRepositoryByExample(ctx, doer, u, repo, false, false); err != nil {
+		if err := CreateRepositoryByExample(ctx, doer, u, repo, false, false); err != nil {
 			return err
 		}
 
@@ -335,3 +341,136 @@ func CreateRepositoryDirectly(ctx context.Context, doer, u *user_model.User, opt
 
 	return repo, nil
 }
+
+// CreateRepositoryByExample creates a repository for the user/organization.
+func CreateRepositoryByExample(ctx context.Context, doer, u *user_model.User, repo *repo_model.Repository, overwriteOrAdopt, isFork bool) (err error) {
+	if err = repo_model.IsUsableRepoName(repo.Name); err != nil {
+		return err
+	}
+
+	has, err := repo_model.IsRepositoryModelExist(ctx, u, repo.Name)
+	if err != nil {
+		return fmt.Errorf("IsRepositoryExist: %w", err)
+	} else if has {
+		return repo_model.ErrRepoAlreadyExist{
+			Uname: u.Name,
+			Name:  repo.Name,
+		}
+	}
+
+	repoPath := repo_model.RepoPath(u.Name, repo.Name)
+	isExist, err := util.IsExist(repoPath)
+	if err != nil {
+		log.Error("Unable to check if %s exists. Error: %v", repoPath, err)
+		return err
+	}
+	if !overwriteOrAdopt && isExist {
+		log.Error("Files already exist in %s and we are not going to adopt or delete.", repoPath)
+		return repo_model.ErrRepoFilesAlreadyExist{
+			Uname: u.Name,
+			Name:  repo.Name,
+		}
+	}
+
+	if err = db.Insert(ctx, repo); err != nil {
+		return err
+	}
+	if err = repo_model.DeleteRedirect(ctx, u.ID, repo.Name); err != nil {
+		return err
+	}
+
+	// insert units for repo
+	defaultUnits := unit.DefaultRepoUnits
+	if isFork {
+		defaultUnits = unit.DefaultForkRepoUnits
+	}
+	units := make([]repo_model.RepoUnit, 0, len(defaultUnits))
+	for _, tp := range defaultUnits {
+		if tp == unit.TypeIssues {
+			units = append(units, repo_model.RepoUnit{
+				RepoID: repo.ID,
+				Type:   tp,
+				Config: &repo_model.IssuesConfig{
+					EnableTimetracker:                setting.Service.DefaultEnableTimetracking,
+					AllowOnlyContributorsToTrackTime: setting.Service.DefaultAllowOnlyContributorsToTrackTime,
+					EnableDependencies:               setting.Service.DefaultEnableDependencies,
+				},
+			})
+		} else if tp == unit.TypePullRequests {
+			units = append(units, repo_model.RepoUnit{
+				RepoID: repo.ID,
+				Type:   tp,
+				Config: &repo_model.PullRequestsConfig{
+					AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true, AllowFastForwardOnly: true,
+					DefaultMergeStyle: repo_model.MergeStyle(setting.Repository.PullRequest.DefaultMergeStyle),
+					AllowRebaseUpdate: true,
+				},
+			})
+		} else if tp == unit.TypeProjects {
+			units = append(units, repo_model.RepoUnit{
+				RepoID: repo.ID,
+				Type:   tp,
+				Config: &repo_model.ProjectsConfig{ProjectsMode: repo_model.ProjectsModeAll},
+			})
+		} else {
+			units = append(units, repo_model.RepoUnit{
+				RepoID: repo.ID,
+				Type:   tp,
+			})
+		}
+	}
+
+	if err = db.Insert(ctx, units); err != nil {
+		return err
+	}
+
+	// Remember visibility preference.
+	u.LastRepoVisibility = repo.IsPrivate
+	if err = user_model.UpdateUserCols(ctx, u, "last_repo_visibility"); err != nil {
+		return fmt.Errorf("UpdateUserCols: %w", err)
+	}
+
+	if err = user_model.IncrUserRepoNum(ctx, u.ID); err != nil {
+		return fmt.Errorf("IncrUserRepoNum: %w", err)
+	}
+	u.NumRepos++
+
+	// Give access to all members in teams with access to all repositories.
+	if u.IsOrganization() {
+		teams, err := organization.FindOrgTeams(ctx, u.ID)
+		if err != nil {
+			return fmt.Errorf("FindOrgTeams: %w", err)
+		}
+		for _, t := range teams {
+			if t.IncludesAllRepositories {
+				if err := models.AddRepository(ctx, t, repo); err != nil {
+					return fmt.Errorf("AddRepository: %w", err)
+				}
+			}
+		}
+
+		if isAdmin, err := access_model.IsUserRepoAdmin(ctx, repo, doer); err != nil {
+			return fmt.Errorf("IsUserRepoAdmin: %w", err)
+		} else if !isAdmin {
+			// Make creator repo admin if it wasn't assigned automatically
+			if err = AddOrUpdateCollaborator(ctx, repo, doer, perm.AccessModeAdmin); err != nil {
+				return fmt.Errorf("AddCollaborator: %w", err)
+			}
+		}
+	} else if err = access_model.RecalculateAccesses(ctx, repo); err != nil {
+		// Organization automatically called this in AddRepository method.
+		return fmt.Errorf("RecalculateAccesses: %w", err)
+	}
+
+	if setting.Service.AutoWatchNewRepos {
+		if err = repo_model.WatchRepo(ctx, doer, repo, true); err != nil {
+			return fmt.Errorf("WatchRepo: %w", err)
+		}
+	}
+
+	if err = webhook.CopyDefaultWebhooksToRepo(ctx, repo.ID); err != nil {
+		return fmt.Errorf("CopyDefaultWebhooksToRepo: %w", err)
+	}
+
+	return nil
+}
diff --git a/services/repository/fork.go b/services/repository/fork.go
index e114555679..5b24015a03 100644
--- a/services/repository/fork.go
+++ b/services/repository/fork.go
@@ -134,7 +134,7 @@ func ForkRepository(ctx context.Context, doer, owner *user_model.User, opts Fork
 	}()
 
 	err = db.WithTx(ctx, func(txCtx context.Context) error {
-		if err = repo_module.CreateRepositoryByExample(txCtx, doer, owner, repo, false, true); err != nil {
+		if err = CreateRepositoryByExample(txCtx, doer, owner, repo, false, true); err != nil {
 			return err
 		}
 
diff --git a/services/repository/generate.go b/services/repository/generate.go
index 2b95bbcd4d..f2280de8b2 100644
--- a/services/repository/generate.go
+++ b/services/repository/generate.go
@@ -343,7 +343,7 @@ func generateRepository(ctx context.Context, doer, owner *user_model.User, templ
 		ObjectFormatName: templateRepo.ObjectFormatName,
 	}
 
-	if err = repo_module.CreateRepositoryByExample(ctx, doer, owner, generateRepo, false, false); err != nil {
+	if err = CreateRepositoryByExample(ctx, doer, owner, generateRepo, false, false); err != nil {
 		return nil, err
 	}
 
diff --git a/services/repository/transfer.go b/services/repository/transfer.go
index 7ad6b46fa4..301d895337 100644
--- a/services/repository/transfer.go
+++ b/services/repository/transfer.go
@@ -20,7 +20,6 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/globallock"
 	"code.gitea.io/gitea/modules/log"
-	repo_module "code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/util"
 	notify_service "code.gitea.io/gitea/services/notify"
 )
@@ -419,10 +418,7 @@ func StartRepositoryTransfer(ctx context.Context, doer, newOwner *user_model.Use
 		return err
 	}
 	if !hasAccess {
-		if err := repo_module.AddCollaborator(ctx, repo, newOwner); err != nil {
-			return err
-		}
-		if err := repo_model.ChangeCollaborationAccessMode(ctx, repo, newOwner.ID, perm.AccessModeRead); err != nil {
+		if err := AddOrUpdateCollaborator(ctx, repo, newOwner, perm.AccessModeRead); err != nil {
 			return err
 		}
 	}
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index 01b12460ac..b9fb1910a3 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -5095,7 +5095,7 @@
         "tags": [
           "repository"
         ],
-        "summary": "Add a collaborator to a repository",
+        "summary": "Add or Update a collaborator to a repository",
         "operationId": "repoAddCollaborator",
         "parameters": [
           {