Merge branch 'fj-41900-import-endpoint-with-overwrite-support' into 'master'

Extend API for importing a project export with overwrite support

Closes #41900

See merge request gitlab-org/gitlab-ce!17883

37 files changed, 1439 insertions, 13 deletions

diff --git a/app/models/group.rb b/app/models/group.rb
index 3cfe21ac93b..8ff781059cc 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -286,6 +286,10 @@ class Group < Namespace
     false
   end
 
+  def refresh_project_authorizations
+    refresh_members_authorized_projects(blocking: false)
+  end
+
   private
 
   def update_two_factor_requirement
diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index e350b675639..2b63aa33222 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -252,6 +252,10 @@ class Namespace < ActiveRecord::Base
     []
   end
 
+  def refresh_project_authorizations
+    owner.refresh_authorized_projects
+  end
+
   private
 
   def path_or_parent_changed?
diff --git a/app/models/project.rb b/app/models/project.rb
index 1b29cbf28d2..96907f3b23d 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -1472,7 +1472,9 @@ class Project < ActiveRecord::Base
   end
 
   def rename_repo_notify!
-    send_move_instructions(full_path_was)
+    # When we import a project overwriting the original project, there
+    # is a move operation. In that case we don't want to send the instructions.
+    send_move_instructions(full_path_was) unless started?
     expires_full_path_cache
 
     self.old_path_with_namespace = full_path_was
diff --git a/app/services/projects/base_move_relations_service.rb b/app/services/projects/base_move_relations_service.rb
new file mode 100644
index 00000000000..e8fd3ef57e5
--- /dev/null
+++ b/app/services/projects/base_move_relations_service.rb
@@ -0,0 +1,22 @@
+module Projects
+  class BaseMoveRelationsService < BaseService
+    attr_reader :source_project
+    def execute(source_project, remove_remaining_elements: true)
+      return if source_project.blank?
+
+      @source_project = source_project
+
+      true
+    end
+
+    private
+
+    def prepare_relation(relation, id_param = :id)
+      if Gitlab::Database.postgresql?
+        relation
+      else
+        relation.model.where("#{id_param}": relation.pluck(id_param))
+      end
+    end
+  end
+end
diff --git a/app/services/projects/destroy_service.rb b/app/services/projects/destroy_service.rb
index 114762c208e..aa14206db3b 100644
--- a/app/services/projects/destroy_service.rb
+++ b/app/services/projects/destroy_service.rb
@@ -46,6 +46,20 @@ module Projects
       raise
     end
 
+    def attempt_repositories_rollback
+      return unless @project
+
+      flush_caches(@project)
+
+      unless mv_repository(removal_path(repo_path), repo_path)
+        raise_error('Failed to restore project repository. Please contact the administrator.')
+      end
+
+      unless mv_repository(removal_path(wiki_path), wiki_path)
+        raise_error('Failed to restore wiki repository. Please contact the administrator.')
+      end
+    end
+
     private
 
     def repo_path
@@ -70,12 +84,9 @@ module Projects
       # Skip repository removal. We use this flag when remove user or group
       return true if params[:skip_repo] == true
 
-      # There is a possibility project does not have repository or wiki
-      return true unless gitlab_shell.exists?(project.repository_storage_path, path + '.git')
-
       new_path = removal_path(path)
 
-      if gitlab_shell.mv_repository(project.repository_storage_path, path, new_path)
+      if mv_repository(path, new_path)
         log_info("Repository \"#{path}\" moved to \"#{new_path}\"")
 
         project.run_after_commit do
@@ -87,6 +98,13 @@ module Projects
       end
     end
 
+    def mv_repository(from_path, to_path)
+      # There is a possibility project does not have repository or wiki
+      return true unless gitlab_shell.exists?(project.repository_storage_path, from_path + '.git')
+
+      gitlab_shell.mv_repository(project.repository_storage_path, from_path, to_path)
+    end
+
     def attempt_rollback(project, message)
       return unless project
 
diff --git a/app/services/projects/gitlab_projects_import_service.rb b/app/services/projects/gitlab_projects_import_service.rb
index fb4afb85588..a16268f4fd2 100644
--- a/app/services/projects/gitlab_projects_import_service.rb
+++ b/app/services/projects/gitlab_projects_import_service.rb
@@ -15,9 +15,18 @@ module Projects
       file = params.delete(:file)
       FileUtils.copy_entry(file.path, import_upload_path)
 
+      @overwrite = params.delete(:overwrite)
+      data = {}
+      data[:override_params] = @override_params if @override_params
+
+      if overwrite_project?
+        data[:original_path] = params[:path]
+        params[:path] += "-#{tmp_filename}"
+      end
+
       params[:import_type] = 'gitlab_project'
       params[:import_source] = import_upload_path
-      params[:import_data] = { data: { override_params: @override_params } } if @override_params
+      params[:import_data] = { data: data } if data.present?
 
       ::Projects::CreateService.new(current_user, params).execute
     end
@@ -31,5 +40,17 @@ module Projects
     def tmp_filename
       SecureRandom.hex
     end
+
+    def overwrite_project?
+      @overwrite && project_with_same_full_path?
+    end
+
+    def project_with_same_full_path?
+      Project.find_by_full_path("#{current_namespace.full_path}/#{params[:path]}").present?
+    end
+
+    def current_namespace
+      @current_namespace ||= Namespace.find_by(id: params[:namespace_id])
+    end
   end
 end
diff --git a/app/services/projects/move_access_service.rb b/app/services/projects/move_access_service.rb
new file mode 100644
index 00000000000..3af3a22d486
--- /dev/null
+++ b/app/services/projects/move_access_service.rb
@@ -0,0 +1,25 @@
+module Projects
+  class MoveAccessService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      @project.with_transaction_returning_status do
+        if @project.namespace != source_project.namespace
+          @project.run_after_commit do
+            source_project.namespace.refresh_project_authorizations
+            self.namespace.refresh_project_authorizations
+          end
+        end
+
+        ::Projects::MoveProjectMembersService.new(@project, @current_user)
+          .execute(source_project, remove_remaining_elements: remove_remaining_elements)
+        ::Projects::MoveProjectGroupLinksService.new(@project, @current_user)
+          .execute(source_project, remove_remaining_elements: remove_remaining_elements)
+        ::Projects::MoveProjectAuthorizationsService.new(@project, @current_user)
+          .execute(source_project, remove_remaining_elements: remove_remaining_elements)
+
+        success
+      end
+    end
+  end
+end
diff --git a/app/services/projects/move_deploy_keys_projects_service.rb b/app/services/projects/move_deploy_keys_projects_service.rb
new file mode 100644
index 00000000000..dde420655b0
--- /dev/null
+++ b/app/services/projects/move_deploy_keys_projects_service.rb
@@ -0,0 +1,31 @@
+module Projects
+  class MoveDeployKeysProjectsService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_deploy_keys_projects
+        remove_remaining_deploy_keys_projects if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_deploy_keys_projects
+      prepare_relation(non_existent_deploy_keys_projects)
+        .update_all(project_id: @project.id)
+    end
+
+    def non_existent_deploy_keys_projects
+      source_project.deploy_keys_projects
+                    .joins(:deploy_key)
+                    .where.not(keys: { fingerprint: @project.deploy_keys.select(:fingerprint) })
+    end
+
+    def remove_remaining_deploy_keys_projects
+      source_project.deploy_keys_projects.destroy_all
+    end
+  end
+end
diff --git a/app/services/projects/move_forks_service.rb b/app/services/projects/move_forks_service.rb
new file mode 100644
index 00000000000..d2901ea1457
--- /dev/null
+++ b/app/services/projects/move_forks_service.rb
@@ -0,0 +1,42 @@
+module Projects
+  class MoveForksService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super && source_project.fork_network
+
+      Project.transaction(requires_new: true) do
+        move_forked_project_links
+        move_fork_network_members
+        update_root_project
+        refresh_forks_count
+
+        success
+      end
+    end
+
+    private
+
+    def move_forked_project_links
+      # Update ancestor
+      ForkedProjectLink.where(forked_to_project: source_project)
+                       .update_all(forked_to_project_id: @project.id)
+
+      # Update the descendants
+      ForkedProjectLink.where(forked_from_project: source_project)
+                       .update_all(forked_from_project_id: @project.id)
+    end
+
+    def move_fork_network_members
+      ForkNetworkMember.where(project: source_project).update_all(project_id: @project.id)
+      ForkNetworkMember.where(forked_from_project: source_project).update_all(forked_from_project_id: @project.id)
+    end
+
+    def update_root_project
+      # Update root network project
+      ForkNetwork.where(root_project: source_project).update_all(root_project_id: @project.id)
+    end
+
+    def refresh_forks_count
+      Projects::ForksCountService.new(@project).refresh_cache
+    end
+  end
+end
diff --git a/app/services/projects/move_lfs_objects_projects_service.rb b/app/services/projects/move_lfs_objects_projects_service.rb
new file mode 100644
index 00000000000..298da5f1a82
--- /dev/null
+++ b/app/services/projects/move_lfs_objects_projects_service.rb
@@ -0,0 +1,29 @@
+module Projects
+  class MoveLfsObjectsProjectsService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_lfs_objects_projects
+        remove_remaining_lfs_objects_project if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_lfs_objects_projects
+      prepare_relation(non_existent_lfs_objects_projects)
+        .update_all(project_id: @project.lfs_storage_project.id)
+    end
+
+    def remove_remaining_lfs_objects_project
+      source_project.lfs_objects_projects.destroy_all
+    end
+
+    def non_existent_lfs_objects_projects
+      source_project.lfs_objects_projects.where.not(lfs_object: @project.lfs_objects)
+    end
+  end
+end
diff --git a/app/services/projects/move_notification_settings_service.rb b/app/services/projects/move_notification_settings_service.rb
new file mode 100644
index 00000000000..f7be461a5da
--- /dev/null
+++ b/app/services/projects/move_notification_settings_service.rb
@@ -0,0 +1,38 @@
+module Projects
+  class MoveNotificationSettingsService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_notification_settings
+        remove_remaining_notification_settings if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_notification_settings
+      prepare_relation(non_existent_notifications)
+        .update_all(source_id: @project.id)
+    end
+
+    # Remove remaining notification settings from source_project
+    def remove_remaining_notification_settings
+      source_project.notification_settings.destroy_all
+    end
+
+    # Get users of current notification_settings
+    def users_in_target_project
+      @project.notification_settings.select(:user_id)
+    end
+
+    # Look for notification_settings in source_project that are not in the target project
+    def non_existent_notifications
+      source_project.notification_settings
+        .select(:id)
+        .where.not(user_id: users_in_target_project)
+    end
+  end
+end
diff --git a/app/services/projects/move_project_authorizations_service.rb b/app/services/projects/move_project_authorizations_service.rb
new file mode 100644
index 00000000000..5ef12fc49e5
--- /dev/null
+++ b/app/services/projects/move_project_authorizations_service.rb
@@ -0,0 +1,40 @@
+# NOTE: This service cannot be used directly because it is part of a
+# a bigger process. Instead, use the service MoveAccessService which moves
+# project memberships, project group links, authorizations and refreshes
+# the authorizations if neccessary
+module Projects
+  class MoveProjectAuthorizationsService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_project_authorizations
+
+        remove_remaining_authorizations if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_project_authorizations
+      prepare_relation(non_existent_authorization, :user_id)
+        .update_all(project_id: @project.id)
+    end
+
+    def remove_remaining_authorizations
+      # I think because the Project Authorization table does not have a primary key
+      # it brings a lot a problems/bugs. First, Rails raises PG::SyntaxException if we use
+      # destroy_all instead of delete_all.
+      source_project.project_authorizations.delete_all(:delete_all)
+    end
+
+    # Look for authorizations in source_project that are not in the target project
+    def non_existent_authorization
+      source_project.project_authorizations
+                    .select(:user_id)
+                    .where.not(user: @project.authorized_users)
+    end
+  end
+end
diff --git a/app/services/projects/move_project_group_links_service.rb b/app/services/projects/move_project_group_links_service.rb
new file mode 100644
index 00000000000..dbeffd7dae9
--- /dev/null
+++ b/app/services/projects/move_project_group_links_service.rb
@@ -0,0 +1,40 @@
+# NOTE: This service cannot be used directly because it is part of a
+# a bigger process. Instead, use the service MoveAccessService which moves
+# project memberships, project group links, authorizations and refreshes
+# the authorizations if neccessary
+module Projects
+  class MoveProjectGroupLinksService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_group_links
+        remove_remaining_project_group_links if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_group_links
+      prepare_relation(non_existent_group_links)
+        .update_all(project_id: @project.id)
+    end
+
+    # Remove remaining project group links from source_project
+    def remove_remaining_project_group_links
+      source_project.reload.project_group_links.destroy_all
+    end
+
+    def group_links_in_target_project
+      @project.project_group_links.select(:group_id)
+    end
+
+    # Look for groups in source_project that are not in the target project
+    def non_existent_group_links
+      source_project.project_group_links
+                    .where.not(group_id: group_links_in_target_project)
+    end
+  end
+end
diff --git a/app/services/projects/move_project_members_service.rb b/app/services/projects/move_project_members_service.rb
new file mode 100644
index 00000000000..22a5f0a3fe6
--- /dev/null
+++ b/app/services/projects/move_project_members_service.rb
@@ -0,0 +1,40 @@
+# NOTE: This service cannot be used directly because it is part of a
+# a bigger process. Instead, use the service MoveAccessService which moves
+# project memberships, project group links, authorizations and refreshes
+# the authorizations if neccessary
+module Projects
+  class MoveProjectMembersService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      Project.transaction(requires_new: true) do
+        move_project_members
+        remove_remaining_members if remove_remaining_elements
+
+        success
+      end
+    end
+
+    private
+
+    def move_project_members
+      prepare_relation(non_existent_members).update_all(source_id: @project.id)
+    end
+
+    def remove_remaining_members
+      # Remove remaining members and authorizations from source_project
+      source_project.project_members.destroy_all
+    end
+
+    def project_members_in_target_project
+      @project.project_members.select(:user_id)
+    end
+
+    # Look for members in source_project that are not in the target project
+    def non_existent_members
+      source_project.members
+                    .select(:id)
+                    .where.not(user_id: @project.project_members.select(:user_id))
+    end
+  end
+end
diff --git a/app/services/projects/move_users_star_projects_service.rb b/app/services/projects/move_users_star_projects_service.rb
new file mode 100644
index 00000000000..079fd5b9685
--- /dev/null
+++ b/app/services/projects/move_users_star_projects_service.rb
@@ -0,0 +1,20 @@
+module Projects
+  class MoveUsersStarProjectsService < BaseMoveRelationsService
+    def execute(source_project, remove_remaining_elements: true)
+      return unless super
+
+      user_stars = source_project.users_star_projects
+
+      return unless user_stars.any?
+
+      Project.transaction(requires_new: true) do
+        user_stars.update_all(project_id: @project.id)
+
+        Project.reset_counters @project.id, :users_star_projects
+        Project.reset_counters source_project.id, :users_star_projects
+
+        success
+      end
+    end
+  end
+end
diff --git a/app/services/projects/overwrite_project_service.rb b/app/services/projects/overwrite_project_service.rb
new file mode 100644
index 00000000000..ce94f147aa9
--- /dev/null
+++ b/app/services/projects/overwrite_project_service.rb
@@ -0,0 +1,69 @@
+module Projects
+  class OverwriteProjectService < BaseService
+    def execute(source_project)
+      return unless source_project && source_project.namespace == @project.namespace
+
+      Project.transaction do
+        move_before_destroy_relationships(source_project)
+        destroy_old_project(source_project)
+        rename_project(source_project.name, source_project.path)
+
+        @project
+      end
+    # Projects::DestroyService can raise Exceptions, but we don't want
+    # to pass that kind of exception to the caller. Instead, we change it
+    # for a StandardError exception
+    rescue Exception => e # rubocop:disable Lint/RescueException
+      attempt_restore_repositories(source_project)
+
+      if e.class == Exception
+        raise StandardError, e.message
+      else
+        raise
+      end
+    end
+
+    private
+
+    def move_before_destroy_relationships(source_project)
+      options = { remove_remaining_elements: false }
+
+      ::Projects::MoveUsersStarProjectsService.new(@project, @current_user).execute(source_project, options)
+      ::Projects::MoveAccessService.new(@project, @current_user).execute(source_project, options)
+      ::Projects::MoveDeployKeysProjectsService.new(@project, @current_user).execute(source_project, options)
+      ::Projects::MoveNotificationSettingsService.new(@project, @current_user).execute(source_project, options)
+      ::Projects::MoveForksService.new(@project, @current_user).execute(source_project, options)
+      ::Projects::MoveLfsObjectsProjectsService.new(@project, @current_user).execute(source_project, options)
+      add_source_project_to_fork_network(source_project)
+    end
+
+    def destroy_old_project(source_project)
+      # Delete previous project (synchronously) and unlink relations
+      ::Projects::DestroyService.new(source_project, @current_user).execute
+    end
+
+    def rename_project(name, path)
+      # Update de project's name and path to the original name/path
+      ::Projects::UpdateService.new(@project,
+                                    @current_user,
+                                    { name: name, path: path })
+                               .execute
+    end
+
+    def attempt_restore_repositories(project)
+      ::Projects::DestroyService.new(project, @current_user).attempt_repositories_rollback
+    end
+
+    def add_source_project_to_fork_network(source_project)
+      return unless @project.fork_network
+
+      # Because he have moved all references in the fork network from the source_project
+      # we won't be able to query the database (only through its cached data),
+      # for its former relationships. That's why we're adding it to the network
+      # as a fork of the target project
+      ForkNetworkMember.create!(fork_network: @project.fork_network,
+                                project: source_project,
+                                forked_from_project: @project)
+    end
+  end
+end
diff --git a/changelogs/unreleased/fj-41900-import-endpoint-with-overwrite-support.yml b/changelogs/unreleased/fj-41900-import-endpoint-with-overwrite-support.yml
new file mode 100644
index 00000000000..0553cc684ce
--- /dev/null
+++ b/changelogs/unreleased/fj-41900-import-endpoint-with-overwrite-support.yml
@@ -0,0 +1,5 @@
+---
+title: Extend API for importing a project export with overwrite support
+merge_request: 17883
+author:
+type: added
diff --git a/doc/api/project_import_export.md b/doc/api/project_import_export.md
index 995f10571d0..d8f61852b11 100644
--- a/doc/api/project_import_export.md
+++ b/doc/api/project_import_export.md
@@ -111,6 +111,7 @@ POST /projects/import
 | `namespace` | integer/string | no | The ID or path of the namespace that the project will be imported to. Defaults to the current user's namespace |
 | `file` | string | yes | The file to be uploaded |
 | `path` | string | yes | Name and path for new project |
+| `overwrite` | boolean | no | If there is a project with the same path the import will overwrite it. Default to false |
 | `override_params` | Hash | no | Supports all fields defined in the [Project API](projects.md)] |
 
 The override params passed will take precendence over all values defined inside the export file.
diff --git a/lib/api/project_import.rb b/lib/api/project_import.rb
index 303b58a5942..bc5152e539f 100644
--- a/lib/api/project_import.rb
+++ b/lib/api/project_import.rb
@@ -26,6 +26,7 @@ module API
         requires :path, type: String, desc: 'The new project path and name'
         requires :file, type: File, desc: 'The project export file to be imported'
         optional :namespace, type: String, desc: "The ID or name of the namespace that the project will be imported into. Defaults to the current user's namespace."
+        optional :overwrite, type: Boolean, default: false, desc: 'If there is a project in the same namespace and with the same name overwrite it'
         optional :override_params,
                  type: Hash,
                  desc: 'New project params to override values in the export' do
@@ -50,7 +51,8 @@ module API
         project_params = {
             path: import_params[:path],
             namespace_id: namespace.id,
-            file: import_params[:file]['tempfile']
+            file: import_params[:file]['tempfile'],
+            overwrite: import_params[:overwrite]
         }
 
         override_params = import_params.delete(:override_params)
diff --git a/lib/gitlab/import_export/importer.rb b/lib/gitlab/import_export/importer.rb
index c490bf059d2..63cab07324a 100644
--- a/lib/gitlab/import_export/importer.rb
+++ b/lib/gitlab/import_export/importer.rb
@@ -1,6 +1,9 @@
 module Gitlab
   module ImportExport
     class Importer
+      include Gitlab::Allowable
+      include Gitlab::Utils::StrongMemoize
+
       def self.imports_repository?
         true
       end
@@ -13,12 +16,14 @@ module Gitlab
       end
 
       def execute
-        if import_file && check_version! && restorers.all?(&:restore)
+        if import_file && check_version! && restorers.all?(&:restore) && overwrite_project
           project_tree.restored_project
         else
           raise Projects::ImportService::Error.new(@shared.errors.join(', '))
         end
-
+      rescue => e
+        raise Projects::ImportService::Error.new(e.message)
+      ensure
         remove_import_file
       end
 
@@ -26,7 +31,7 @@ module Gitlab
 
       def restorers
         [repo_restorer, wiki_restorer, project_tree, avatar_restorer,
-         uploads_restorer, lfs_restorer]
+         uploads_restorer, lfs_restorer, statistics_restorer]
       end
 
       def import_file
@@ -69,6 +74,10 @@ module Gitlab
         Gitlab::ImportExport::LfsRestorer.new(project: project_tree.restored_project, shared: @shared)
       end
 
+      def statistics_restorer
+        Gitlab::ImportExport::StatisticsRestorer.new(project: project_tree.restored_project, shared: @shared)
+      end
+
       def path_with_namespace
         File.join(@project.namespace.full_path, @project.path)
       end
@@ -84,6 +93,33 @@ module Gitlab
       def remove_import_file
         FileUtils.rm_rf(@archive_file)
       end
+
+      def overwrite_project
+        project = project_tree.restored_project
+
+        return unless can?(@current_user, :admin_namespace, project.namespace)
+
+        if overwrite_project?
+          ::Projects::OverwriteProjectService.new(project, @current_user)
+                                             .execute(project_to_overwrite)
+        end
+
+        true
+      end
+
+      def original_path
+        @project.import_data&.data&.fetch('original_path', nil)
+      end
+
+      def overwrite_project?
+        original_path.present? && project_to_overwrite.present?
+      end
+
+      def project_to_overwrite
+        strong_memoize(:project_to_overwrite) do
+          Project.find_by_full_path("#{@project.namespace.full_path}/#{original_path}")
+        end
+      end
     end
   end
 end
diff --git a/lib/gitlab/import_export/project_tree_restorer.rb b/lib/gitlab/import_export/project_tree_restorer.rb
index 2c315207298..d5590dde40f 100644
--- a/lib/gitlab/import_export/project_tree_restorer.rb
+++ b/lib/gitlab/import_export/project_tree_restorer.rb
@@ -92,7 +92,7 @@ module Gitlab
       end
 
       def override_params
-        return {} unless params = @project.import_data&.data&.fetch('override_params')
+        return {} unless params = @project.import_data&.data&.fetch('override_params', nil)
 
         @override_params ||= params.select do |key, _value|
           Project.column_names.include?(key.to_s) &&
diff --git a/lib/gitlab/import_export/statistics_restorer.rb b/lib/gitlab/import_export/statistics_restorer.rb
new file mode 100644
index 00000000000..bcdd9c12c85
--- /dev/null
+++ b/lib/gitlab/import_export/statistics_restorer.rb
@@ -0,0 +1,17 @@
+module Gitlab
+  module ImportExport
+    class StatisticsRestorer
+      def initialize(project:, shared:)
+        @project = project
+        @shared = shared
+      end
+
+      def restore
+        @project.statistics.refresh!
+      rescue => e
+        @shared.error(e)
+        false
+      end
+    end
+  end
+end
diff --git a/spec/factories/users_star_projects.rb b/spec/factories/users_star_projects.rb
new file mode 100644
index 00000000000..6afd08a2084
--- /dev/null
+++ b/spec/factories/users_star_projects.rb
@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :users_star_project do
+    project
+    user
+  end
+end
diff --git a/spec/lib/gitlab/import_export/importer_spec.rb b/spec/lib/gitlab/import_export/importer_spec.rb
index d75416f2a62..991e354f499 100644
--- a/spec/lib/gitlab/import_export/importer_spec.rb
+++ b/spec/lib/gitlab/import_export/importer_spec.rb
@@ -1,6 +1,7 @@
 require 'spec_helper'
 
 describe Gitlab::ImportExport::Importer do
+  let(:user) { create(:user) }
   let(:test_path) { "#{Dir.tmpdir}/importer_spec" }
   let(:shared) { project.import_export_shared }
   let(:project) { create(:project, import_source: File.join(test_path, 'exported-project.gz')) }
@@ -11,6 +12,7 @@ describe Gitlab::ImportExport::Importer do
     allow_any_instance_of(Gitlab::ImportExport).to receive(:storage_path).and_return(test_path)
     FileUtils.mkdir_p(shared.export_path)
     FileUtils.cp(Rails.root.join('spec', 'fixtures', 'exported-project.gz'), test_path)
+    allow(subject).to receive(:remove_import_file)
   end
 
   after do
@@ -42,7 +44,8 @@ describe Gitlab::ImportExport::Importer do
         Gitlab::ImportExport::RepoRestorer,
         Gitlab::ImportExport::WikiRestorer,
         Gitlab::ImportExport::UploadsRestorer,
-        Gitlab::ImportExport::LfsRestorer
+        Gitlab::ImportExport::LfsRestorer,
+        Gitlab::ImportExport::StatisticsRestorer
       ].each do |restorer|
         it "calls the #{restorer}" do
           fake_restorer = double(restorer.to_s)
@@ -60,5 +63,42 @@ describe Gitlab::ImportExport::Importer do
         importer.execute
       end
     end
+
+    context 'when project successfully restored' do
+      let!(:existing_project) { create(:project, namespace: user.namespace) }
+      let(:project) { create(:project, namespace: user.namespace, name: 'whatever', path: 'whatever') }
+
+      before do
+        restorers = double
+
+        allow(subject).to receive(:import_file).and_return(true)
+        allow(subject).to receive(:check_version!).and_return(true)
+        allow(subject).to receive(:restorers).and_return(restorers)
+        allow(restorers).to receive(:all?).and_return(true)
+        allow(project).to receive(:import_data).and_return(double(data: { 'original_path' => existing_project.path }))
+      end
+
+      context 'when import_data' do
+        context 'has original_path' do
+          it 'overwrites existing project' do
+            expect_any_instance_of(::Projects::OverwriteProjectService).to receive(:execute).with(existing_project)
+
+            subject.execute
+          end
+        end
+
+        context 'has not original_path' do
+          before do
+            allow(project).to receive(:import_data).and_return(double(data: {}))
+          end
+
+          it 'does not call the overwrite service' do
+            expect_any_instance_of(::Projects::OverwriteProjectService).not_to receive(:execute).with(existing_project)
+
+            subject.execute
+          end
+        end
+      end
+    end
   end
 end
diff --git a/spec/requests/api/project_import_spec.rb b/spec/requests/api/project_import_spec.rb
index 5d13e6de741..f68057a92a1 100644
--- a/spec/requests/api/project_import_spec.rb
+++ b/spec/requests/api/project_import_spec.rb
@@ -114,6 +114,29 @@ describe API::ProjectImport do
       expect(import_project.description).to eq('Hello world')
     end
 
+    context 'when target path already exists in namespace' do
+      let(:existing_project) { create(:project, namespace: user.namespace) }
+
+      it 'does not schedule an import' do
+        expect_any_instance_of(Project).not_to receive(:import_schedule)
+
+        post api('/projects/import', user), path: existing_project.path, file: fixture_file_upload(file)
+
+        expect(response).to have_gitlab_http_status(400)
+        expect(json_response['message']).to eq('Name has already been taken')
+      end
+
+      context 'when param overwrite is true' do
+        it 'schedules an import' do
+          stub_import(user.namespace)
+
+          post api('/projects/import', user), path: existing_project.path, file: fixture_file_upload(file), overwrite: true
+
+          expect(response).to have_gitlab_http_status(201)
+        end
+      end
+    end
+
     def stub_import(namespace)
       expect_any_instance_of(Project).to receive(:import_schedule)
       expect(::Projects::CreateService).to receive(:new).with(user, hash_including(namespace_id: namespace.id)).and_call_original
diff --git a/spec/services/projects/destroy_service_spec.rb b/spec/services/projects/destroy_service_spec.rb
index 9bb1cda565c..a66e3c5e995 100644
--- a/spec/services/projects/destroy_service_spec.rb
+++ b/spec/services/projects/destroy_service_spec.rb
@@ -248,6 +248,28 @@ describe Projects::DestroyService do
     end
   end
 
+  context '#attempt_restore_repositories' do
+    let(:path) { project.disk_path + '.git' }
+
+    before do
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, path)).to be_truthy
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, remove_path)).to be_falsey
+
+      # Dont run sidekiq to check if renamed repository exists
+      Sidekiq::Testing.fake! { destroy_project(project, user, {}) }
+
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, path)).to be_falsey
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, remove_path)).to be_truthy
+    end
+
+    it 'restores the repositories' do
+      Sidekiq::Testing.fake! { described_class.new(project, user).attempt_repositories_rollback }
+
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, path)).to be_truthy
+      expect(project.gitlab_shell.exists?(project.repository_storage_path, remove_path)).to be_falsey
+    end
+  end
+
   def destroy_project(project, user, params = {})
     if async
       Projects::DestroyService.new(project, user, params).async_execute
diff --git a/spec/services/projects/gitlab_projects_import_service_spec.rb b/spec/services/projects/gitlab_projects_import_service_spec.rb
index 880b2aae66a..ee1a886f5d6 100644
--- a/spec/services/projects/gitlab_projects_import_service_spec.rb
+++ b/spec/services/projects/gitlab_projects_import_service_spec.rb
@@ -4,7 +4,8 @@ describe Projects::GitlabProjectsImportService do
   set(:namespace) { create(:namespace) }
   let(:path) { 'test-path' }
   let(:file) { fixture_file_upload(Rails.root + 'spec/fixtures/doc_sample.txt', 'text/plain') }
-  let(:import_params) { { namespace_id: namespace.id, path: path, file: file } }
+  let(:overwrite) { false }
+  let(:import_params) { { namespace_id: namespace.id, path: path, file: file, overwrite: overwrite } }
   subject { described_class.new(namespace.owner, import_params) }
 
   describe '#execute' do
@@ -37,5 +38,28 @@ describe Projects::GitlabProjectsImportService do
         expect(project.import_data.data['override_params']['description']).to eq('Hello')
       end
     end
+
+    context 'when there is a project with the same path' do
+      let(:existing_project) { create(:project, namespace: namespace) }
+      let(:path) { existing_project.path}
+
+      it 'does not create the project' do
+        project = subject.execute
+
+        expect(project).to be_invalid
+        expect(project).not_to be_persisted
+      end
+
+      context 'when overwrite param is set' do
+        let(:overwrite) { true }
+
+        it 'creates a project in a temporary full_path' do
+          project = subject.execute
+
+          expect(project).to be_valid
+          expect(project).to be_persisted
+        end
+      end
+    end
   end
 end
diff --git a/spec/services/projects/move_access_service_spec.rb b/spec/services/projects/move_access_service_spec.rb
new file mode 100644
index 00000000000..a820ebd91f4
--- /dev/null
+++ b/spec/services/projects/move_access_service_spec.rb
@@ -0,0 +1,114 @@
+require 'spec_helper'
+
+describe Projects::MoveAccessService do
+  let(:user) { create(:user) }
+  let(:group) { create(:group) }
+  let(:project_with_access) { create(:project, namespace: user.namespace) }
+  let(:master_user) { create(:user) }
+  let(:reporter_user) { create(:user) }
+  let(:developer_user) { create(:user) }
+  let(:master_group) { create(:group) }
+  let(:reporter_group) { create(:group) }
+  let(:developer_group) { create(:group) }
+
+  before do
+    project_with_access.add_master(master_user)
+    project_with_access.add_developer(developer_user)
+    project_with_access.add_reporter(reporter_user)
+    project_with_access.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+    project_with_access.project_group_links.create(group: developer_group, group_access: Gitlab::Access::DEVELOPER)
+    project_with_access.project_group_links.create(group: reporter_group, group_access: Gitlab::Access::REPORTER)
+  end
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    shared_examples 'move the accesses' do
+      it do
+        expect(project_with_access.project_members.count).to eq 4
+        expect(project_with_access.project_group_links.count).to eq 3
+        expect(project_with_access.authorized_users.count).to eq 4
+
+        subject.execute(project_with_access)
+
+        expect(project_with_access.project_members.count).to eq 0
+        expect(project_with_access.project_group_links.count).to eq 0
+        expect(project_with_access.authorized_users.count).to eq 1
+        expect(target_project.project_members.count).to eq 4
+        expect(target_project.project_group_links.count).to eq 3
+        expect(target_project.authorized_users.count).to eq 4
+      end
+
+      it 'rollbacks if an exception is raised' do
+        allow(subject).to receive(:success).and_raise(StandardError)
+
+        expect { subject.execute(project_with_groups) }.to raise_error(StandardError)
+
+        expect(project_with_access.project_members.count).to eq 4
+        expect(project_with_access.project_group_links.count).to eq 3
+        expect(project_with_access.authorized_users.count).to eq 4
+      end
+    end
+
+    context 'when both projects are in the same namespace' do
+      let(:target_project) { create(:project, namespace: user.namespace) }
+
+      it 'does not refresh project owner authorized projects' do
+        allow(project_with_access).to receive(:namespace).and_return(user.namespace)
+        expect(project_with_access.namespace).not_to receive(:refresh_project_authorizations)
+        expect(target_project.namespace).not_to receive(:refresh_project_authorizations)
+
+        subject.execute(project_with_access)
+      end
+
+      it_behaves_like 'move the accesses'
+    end
+
+    context 'when projects are in different namespaces' do
+      let(:target_project) { create(:project, namespace: group) }
+
+      before do
+        group.add_owner(user)
+      end
+
+      it 'refreshes both project owner authorized projects' do
+        allow(project_with_access).to receive(:namespace).and_return(user.namespace)
+        expect(user.namespace).to receive(:refresh_project_authorizations).once
+        expect(group).to receive(:refresh_project_authorizations).once
+
+        subject.execute(project_with_access)
+      end
+
+      it_behaves_like 'move the accesses'
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:target_project) { create(:project, namespace: user.namespace) }
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining memberships' do
+        target_project.add_master(master_user)
+
+        subject.execute(project_with_access, options)
+
+        expect(project_with_access.project_members.count).not_to eq 0
+      end
+
+      it 'does not remove remaining group links' do
+        target_project.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+
+        subject.execute(project_with_access, options)
+
+        expect(project_with_access.project_group_links.count).not_to eq 0
+      end
+
+      it 'does not remove remaining authorizations' do
+        target_project.add_developer(developer_user)
+
+        subject.execute(project_with_access, options)
+
+        expect(project_with_access.project_authorizations.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_deploy_keys_projects_service_spec.rb b/spec/services/projects/move_deploy_keys_projects_service_spec.rb
new file mode 100644
index 00000000000..c548edf39a8
--- /dev/null
+++ b/spec/services/projects/move_deploy_keys_projects_service_spec.rb
@@ -0,0 +1,58 @@
+require 'spec_helper'
+
+describe Projects::MoveDeployKeysProjectsService do
+  let!(:user) { create(:user) }
+  let!(:project_with_deploy_keys) { create(:project, namespace: user.namespace) }
+  let!(:target_project) { create(:project, namespace: user.namespace) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    before do
+      create_list(:deploy_keys_project, 2, project: project_with_deploy_keys)
+    end
+
+    it 'moves the user\'s deploy keys from one project to another' do
+      expect(project_with_deploy_keys.deploy_keys_projects.count).to eq 2
+      expect(target_project.deploy_keys_projects.count).to eq 0
+
+      subject.execute(project_with_deploy_keys)
+
+      expect(project_with_deploy_keys.deploy_keys_projects.count).to eq 0
+      expect(target_project.deploy_keys_projects.count).to eq 2
+    end
+
+    it 'does not link existent deploy_keys in the current project' do
+      target_project.deploy_keys << project_with_deploy_keys.deploy_keys.first
+
+      expect(project_with_deploy_keys.deploy_keys_projects.count).to eq 2
+      expect(target_project.deploy_keys_projects.count).to eq 1
+
+      subject.execute(project_with_deploy_keys)
+
+      expect(project_with_deploy_keys.deploy_keys_projects.count).to eq 0
+      expect(target_project.deploy_keys_projects.count).to eq 2
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_deploy_keys) }.to raise_error(StandardError)
+
+      expect(project_with_deploy_keys.deploy_keys_projects.count).to eq 2
+      expect(target_project.deploy_keys_projects.count).to eq 0
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining deploy keys projects' do
+        target_project.deploy_keys << project_with_deploy_keys.deploy_keys.first
+
+        subject.execute(project_with_deploy_keys, options)
+
+        expect(project_with_deploy_keys.deploy_keys_projects.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_forks_service_spec.rb b/spec/services/projects/move_forks_service_spec.rb
new file mode 100644
index 00000000000..f4a5a7f9fc2
--- /dev/null
+++ b/spec/services/projects/move_forks_service_spec.rb
@@ -0,0 +1,96 @@
+require 'spec_helper'
+
+describe Projects::MoveForksService do
+  include ProjectForksHelper
+
+  let!(:user) { create(:user) }
+  let!(:project_with_forks) { create(:project, namespace: user.namespace) }
+  let!(:target_project) { create(:project, namespace: user.namespace) }
+  let!(:lvl1_forked_project_1) { fork_project(project_with_forks, user) }
+  let!(:lvl1_forked_project_2) { fork_project(project_with_forks, user) }
+  let!(:lvl2_forked_project_1_1) { fork_project(lvl1_forked_project_1, user) }
+  let!(:lvl2_forked_project_1_2) { fork_project(lvl1_forked_project_1, user) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    context 'when moving a root forked project' do
+      it 'moves the descendant forks' do
+        expect(project_with_forks.forks.count).to eq 2
+        expect(target_project.forks.count).to eq 0
+
+        subject.execute(project_with_forks)
+
+        expect(project_with_forks.forks.count).to eq 0
+        expect(target_project.forks.count).to eq 2
+        expect(lvl1_forked_project_1.forked_from_project).to eq target_project
+        expect(lvl1_forked_project_1.fork_network_member.forked_from_project).to eq target_project
+        expect(lvl1_forked_project_2.forked_from_project).to eq target_project
+        expect(lvl1_forked_project_2.fork_network_member.forked_from_project).to eq target_project
+      end
+
+      it 'updates the fork network' do
+        expect(project_with_forks.fork_network.root_project).to eq project_with_forks
+        expect(project_with_forks.fork_network.fork_network_members.map(&:project)).to include project_with_forks
+
+        subject.execute(project_with_forks)
+
+        expect(target_project.reload.fork_network.root_project).to eq target_project
+        expect(target_project.fork_network.fork_network_members.map(&:project)).not_to include project_with_forks
+      end
+    end
+
+    context 'when moving a intermediate forked project' do
+      it 'moves the descendant forks' do
+        expect(lvl1_forked_project_1.forks.count).to eq 2
+        expect(target_project.forks.count).to eq 0
+
+        subject.execute(lvl1_forked_project_1)
+
+        expect(lvl1_forked_project_1.forks.count).to eq 0
+        expect(target_project.forks.count).to eq 2
+        expect(lvl2_forked_project_1_1.forked_from_project).to eq target_project
+        expect(lvl2_forked_project_1_1.fork_network_member.forked_from_project).to eq target_project
+        expect(lvl2_forked_project_1_2.forked_from_project).to eq target_project
+        expect(lvl2_forked_project_1_2.fork_network_member.forked_from_project).to eq target_project
+      end
+
+      it 'moves the ascendant fork' do
+        subject.execute(lvl1_forked_project_1)
+
+        expect(target_project.forked_from_project).to eq project_with_forks
+        expect(target_project.fork_network_member.forked_from_project).to eq project_with_forks
+      end
+
+      it 'does not update fork network' do
+        subject.execute(lvl1_forked_project_1)
+
+        expect(target_project.reload.fork_network.root_project).to eq project_with_forks
+      end
+    end
+
+    context 'when moving a leaf forked project' do
+      it 'moves the ascendant fork' do
+        subject.execute(lvl2_forked_project_1_1)
+
+        expect(target_project.forked_from_project).to eq lvl1_forked_project_1
+        expect(target_project.fork_network_member.forked_from_project).to eq lvl1_forked_project_1
+      end
+
+      it 'does not update fork network' do
+        subject.execute(lvl2_forked_project_1_1)
+
+        expect(target_project.reload.fork_network.root_project).to eq project_with_forks
+      end
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_forks) }.to raise_error(StandardError)
+
+      expect(project_with_forks.forks.count).to eq 2
+      expect(target_project.forks.count).to eq 0
+    end
+  end
+end
diff --git a/spec/services/projects/move_lfs_objects_projects_service_spec.rb b/spec/services/projects/move_lfs_objects_projects_service_spec.rb
new file mode 100644
index 00000000000..517a24a982a
--- /dev/null
+++ b/spec/services/projects/move_lfs_objects_projects_service_spec.rb
@@ -0,0 +1,55 @@
+require 'spec_helper'
+
+describe Projects::MoveLfsObjectsProjectsService do
+  let!(:user) { create(:user) }
+  let!(:project_with_lfs_objects) { create(:project, namespace: user.namespace) }
+  let!(:target_project) { create(:project, namespace: user.namespace) }
+
+  subject { described_class.new(target_project, user) }
+
+  before do
+    create_list(:lfs_objects_project, 3, project: project_with_lfs_objects)
+  end
+
+  describe '#execute' do
+    it 'links the lfs objects from existent in source project' do
+      expect(target_project.lfs_objects.count).to eq 0
+
+      subject.execute(project_with_lfs_objects)
+
+      expect(project_with_lfs_objects.reload.lfs_objects.count).to eq 0
+      expect(target_project.reload.lfs_objects.count).to eq 3
+    end
+
+    it 'does not link existent lfs_object in the current project' do
+      target_project.lfs_objects << project_with_lfs_objects.lfs_objects.first(2)
+
+      expect(target_project.lfs_objects.count).to eq 2
+
+      subject.execute(project_with_lfs_objects)
+
+      expect(target_project.lfs_objects.count).to eq 3
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_lfs_objects) }.to raise_error(StandardError)
+
+      expect(project_with_lfs_objects.lfs_objects.count).to eq 3
+      expect(target_project.lfs_objects.count).to eq 0
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining lfs objects' do
+        target_project.lfs_objects << project_with_lfs_objects.lfs_objects.first(2)
+
+        subject.execute(project_with_lfs_objects, options)
+
+        expect(project_with_lfs_objects.lfs_objects.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_notification_settings_service_spec.rb b/spec/services/projects/move_notification_settings_service_spec.rb
new file mode 100644
index 00000000000..24d69eef86a
--- /dev/null
+++ b/spec/services/projects/move_notification_settings_service_spec.rb
@@ -0,0 +1,56 @@
+require 'spec_helper'
+
+describe Projects::MoveNotificationSettingsService do
+  let(:user) { create(:user) }
+  let(:project_with_notifications) { create(:project, namespace: user.namespace) }
+  let(:target_project) { create(:project, namespace: user.namespace) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    context 'with notification settings' do
+      before do
+        create_list(:notification_setting, 2, source: project_with_notifications)
+      end
+
+      it 'moves the user\'s notification settings from one project to another' do
+        expect(project_with_notifications.notification_settings.count).to eq 3
+        expect(target_project.notification_settings.count).to eq 1
+
+        subject.execute(project_with_notifications)
+
+        expect(project_with_notifications.notification_settings.count).to eq 0
+        expect(target_project.notification_settings.count).to eq 3
+      end
+
+      it 'rollbacks changes if transaction fails' do
+        allow(subject).to receive(:success).and_raise(StandardError)
+
+        expect { subject.execute(project_with_notifications) }.to raise_error(StandardError)
+
+        expect(project_with_notifications.notification_settings.count).to eq 3
+        expect(target_project.notification_settings.count).to eq 1
+      end
+    end
+
+    it 'does not move existent notification settings in the current project' do
+      expect(project_with_notifications.notification_settings.count).to eq 1
+      expect(target_project.notification_settings.count).to eq 1
+      expect(user.notification_settings.count).to eq 2
+
+      subject.execute(project_with_notifications)
+
+      expect(user.notification_settings.count).to eq 1
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining notification settings' do
+        subject.execute(project_with_notifications, options)
+
+        expect(project_with_notifications.notification_settings.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_project_authorizations_service_spec.rb b/spec/services/projects/move_project_authorizations_service_spec.rb
new file mode 100644
index 00000000000..f7262b9b887
--- /dev/null
+++ b/spec/services/projects/move_project_authorizations_service_spec.rb
@@ -0,0 +1,56 @@
+require 'spec_helper'
+
+describe Projects::MoveProjectAuthorizationsService do
+  let!(:user) { create(:user) }
+  let(:project_with_users) { create(:project, namespace: user.namespace) }
+  let(:target_project) { create(:project, namespace: user.namespace) }
+  let(:master_user) { create(:user) }
+  let(:reporter_user) { create(:user) }
+  let(:developer_user) { create(:user) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    before do
+      project_with_users.add_master(master_user)
+      project_with_users.add_developer(developer_user)
+      project_with_users.add_reporter(reporter_user)
+    end
+
+    it 'moves the authorizations from one project to another' do
+      expect(project_with_users.authorized_users.count).to eq 4
+      expect(target_project.authorized_users.count).to eq 1
+
+      subject.execute(project_with_users)
+
+      expect(project_with_users.authorized_users.count).to eq 0
+      expect(target_project.authorized_users.count).to eq 4
+    end
+
+    it 'does not move existent authorizations to the current project' do
+      target_project.add_master(developer_user)
+      target_project.add_developer(reporter_user)
+
+      expect(project_with_users.authorized_users.count).to eq 4
+      expect(target_project.authorized_users.count).to eq 3
+
+      subject.execute(project_with_users)
+
+      expect(project_with_users.authorized_users.count).to eq 0
+      expect(target_project.authorized_users.count).to eq 4
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining project authorizations' do
+        target_project.add_master(developer_user)
+        target_project.add_developer(reporter_user)
+
+        subject.execute(project_with_users, options)
+
+        expect(project_with_users.project_authorizations.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_project_group_links_service_spec.rb b/spec/services/projects/move_project_group_links_service_spec.rb
new file mode 100644
index 00000000000..e3d06e6d3d7
--- /dev/null
+++ b/spec/services/projects/move_project_group_links_service_spec.rb
@@ -0,0 +1,65 @@
+require 'spec_helper'
+
+describe Projects::MoveProjectGroupLinksService do
+  let!(:user) { create(:user) }
+  let(:project_with_groups) { create(:project, namespace: user.namespace) }
+  let(:target_project) { create(:project, namespace: user.namespace) }
+  let(:master_group) { create(:group) }
+  let(:reporter_group) { create(:group) }
+  let(:developer_group) { create(:group) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    before do
+      project_with_groups.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+      project_with_groups.project_group_links.create(group: developer_group, group_access: Gitlab::Access::DEVELOPER)
+      project_with_groups.project_group_links.create(group: reporter_group, group_access: Gitlab::Access::REPORTER)
+    end
+
+    it 'moves the group links from one project to another' do
+      expect(project_with_groups.project_group_links.count).to eq 3
+      expect(target_project.project_group_links.count).to eq 0
+
+      subject.execute(project_with_groups)
+
+      expect(project_with_groups.project_group_links.count).to eq 0
+      expect(target_project.project_group_links.count).to eq 3
+    end
+
+    it 'does not move existent group links in the current project' do
+      target_project.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+      target_project.project_group_links.create(group: developer_group, group_access: Gitlab::Access::DEVELOPER)
+
+      expect(project_with_groups.project_group_links.count).to eq 3
+      expect(target_project.project_group_links.count).to eq 2
+
+      subject.execute(project_with_groups)
+
+      expect(project_with_groups.project_group_links.count).to eq 0
+      expect(target_project.project_group_links.count).to eq 3
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_groups) }.to raise_error(StandardError)
+
+      expect(project_with_groups.project_group_links.count).to eq 3
+      expect(target_project.project_group_links.count).to eq 0
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining project group links' do
+        target_project.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+        target_project.project_group_links.create(group: developer_group, group_access: Gitlab::Access::DEVELOPER)
+
+        subject.execute(project_with_groups, options)
+
+        expect(project_with_groups.project_group_links.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_project_members_service_spec.rb b/spec/services/projects/move_project_members_service_spec.rb
new file mode 100644
index 00000000000..9c9a2d2fde1
--- /dev/null
+++ b/spec/services/projects/move_project_members_service_spec.rb
@@ -0,0 +1,65 @@
+require 'spec_helper'
+
+describe Projects::MoveProjectMembersService do
+  let!(:user) { create(:user) }
+  let(:project_with_users) { create(:project, namespace: user.namespace) }
+  let(:target_project) { create(:project, namespace: user.namespace) }
+  let(:master_user) { create(:user) }
+  let(:reporter_user) { create(:user) }
+  let(:developer_user) { create(:user) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    before do
+      project_with_users.add_master(master_user)
+      project_with_users.add_developer(developer_user)
+      project_with_users.add_reporter(reporter_user)
+    end
+
+    it 'moves the members from one project to another' do
+      expect(project_with_users.project_members.count).to eq 4
+      expect(target_project.project_members.count).to eq 1
+
+      subject.execute(project_with_users)
+
+      expect(project_with_users.project_members.count).to eq 0
+      expect(target_project.project_members.count).to eq 4
+    end
+
+    it 'does not move existent members to the current project' do
+      target_project.add_master(developer_user)
+      target_project.add_developer(reporter_user)
+
+      expect(project_with_users.project_members.count).to eq 4
+      expect(target_project.project_members.count).to eq 3
+
+      subject.execute(project_with_users)
+
+      expect(project_with_users.project_members.count).to eq 0
+      expect(target_project.project_members.count).to eq 4
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_users) }.to raise_error(StandardError)
+
+      expect(project_with_users.project_members.count).to eq 4
+      expect(target_project.project_members.count).to eq 1
+    end
+
+    context 'when remove_remaining_elements is false' do
+      let(:options) { { remove_remaining_elements: false } }
+
+      it 'does not remove remaining project members' do
+        target_project.add_master(developer_user)
+        target_project.add_developer(reporter_user)
+
+        subject.execute(project_with_users, options)
+
+        expect(project_with_users.project_members.count).not_to eq 0
+      end
+    end
+  end
+end
diff --git a/spec/services/projects/move_users_star_projects_service_spec.rb b/spec/services/projects/move_users_star_projects_service_spec.rb
new file mode 100644
index 00000000000..e0545c5a21b
--- /dev/null
+++ b/spec/services/projects/move_users_star_projects_service_spec.rb
@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+describe Projects::MoveUsersStarProjectsService do
+  let!(:user) { create(:user) }
+  let!(:project_with_stars) { create(:project, namespace: user.namespace) }
+  let!(:target_project) { create(:project, namespace: user.namespace) }
+
+  subject { described_class.new(target_project, user) }
+
+  describe '#execute' do
+    before do
+      create_list(:users_star_project, 2, project: project_with_stars)
+    end
+
+    it 'moves the user\'s stars from one project to another' do
+      expect(project_with_stars.users_star_projects.count).to eq 2
+      expect(project_with_stars.star_count).to eq 2
+      expect(target_project.users_star_projects.count).to eq 0
+      expect(target_project.star_count).to eq 0
+
+      subject.execute(project_with_stars)
+      project_with_stars.reload
+      target_project.reload
+
+      expect(project_with_stars.users_star_projects.count).to eq 0
+      expect(project_with_stars.star_count).to eq 0
+      expect(target_project.users_star_projects.count).to eq 2
+      expect(target_project.star_count).to eq 2
+    end
+
+    it 'rollbacks changes if transaction fails' do
+      allow(subject).to receive(:success).and_raise(StandardError)
+
+      expect { subject.execute(project_with_stars) }.to raise_error(StandardError)
+
+      expect(project_with_stars.users_star_projects.count).to eq 2
+      expect(project_with_stars.star_count).to eq 2
+      expect(target_project.users_star_projects.count).to eq 0
+      expect(target_project.star_count).to eq 0
+    end
+  end
+end
diff --git a/spec/services/projects/overwrite_project_service_spec.rb b/spec/services/projects/overwrite_project_service_spec.rb
new file mode 100644
index 00000000000..252c61f4224
--- /dev/null
+++ b/spec/services/projects/overwrite_project_service_spec.rb
@@ -0,0 +1,198 @@
+require 'spec_helper'
+
+describe Projects::OverwriteProjectService do
+  include ProjectForksHelper
+
+  let(:user) { create(:user) }
+  let(:project_from) { create(:project, namespace: user.namespace) }
+  let(:project_to) { create(:project, namespace: user.namespace) }
+  let!(:lvl1_forked_project_1) { fork_project(project_from, user) }
+  let!(:lvl1_forked_project_2) { fork_project(project_from, user) }
+  let!(:lvl2_forked_project_1_1) { fork_project(lvl1_forked_project_1, user) }
+  let!(:lvl2_forked_project_1_2) { fork_project(lvl1_forked_project_1, user) }
+
+  subject { described_class.new(project_to, user) }
+
+  before do
+    allow(project_to).to receive(:import_data).and_return(double(data: { 'original_path' => project_from.path }))
+  end
+
+  describe '#execute' do
+    shared_examples 'overwrite actions' do
+      it 'moves deploy keys' do
+        deploy_keys_count = project_from.deploy_keys_projects.count
+
+        subject.execute(project_from)
+
+        expect(project_to.deploy_keys_projects.count).to eq deploy_keys_count
+      end
+
+      it 'moves notification settings' do
+        notification_count = project_from.notification_settings.count
+
+        subject.execute(project_from)
+
+        expect(project_to.notification_settings.count).to eq notification_count
+      end
+
+      it 'moves users stars' do
+        stars_count = project_from.users_star_projects.count
+
+        subject.execute(project_from)
+        project_to.reload
+
+        expect(project_to.users_star_projects.count).to eq stars_count
+        expect(project_to.star_count).to eq stars_count
+      end
+
+      it 'moves project group links' do
+        group_links_count = project_from.project_group_links.count
+
+        subject.execute(project_from)
+
+        expect(project_to.project_group_links.count).to eq group_links_count
+      end
+
+      it 'moves memberships and authorizations' do
+        members_count = project_from.project_members.count
+        project_authorizations = project_from.project_authorizations.count
+
+        subject.execute(project_from)
+
+        expect(project_to.project_members.count).to eq members_count
+        expect(project_to.project_authorizations.count).to eq project_authorizations
+      end
+
+      context 'moves lfs objects relationships' do
+        before do
+          create_list(:lfs_objects_project, 3, project: project_from)
+        end
+
+        it do
+          lfs_objects_count = project_from.lfs_objects.count
+
+          subject.execute(project_from)
+
+          expect(project_to.lfs_objects.count).to eq lfs_objects_count
+        end
+      end
+
+      it 'removes the original project' do
+        subject.execute(project_from)
+
+        expect { Project.find(project_from.id) }.to raise_error(ActiveRecord::RecordNotFound)
+      end
+
+      it 'renames the project' do
+        subject.execute(project_from)
+
+        expect(project_to.full_path).to eq project_from.full_path
+      end
+    end
+
+    context 'when project does not have any relation' do
+      it_behaves_like 'overwrite actions'
+    end
+
+    context 'when project with elements' do
+      it_behaves_like 'overwrite actions' do
+        let(:master_user) { create(:user) }
+        let(:reporter_user) { create(:user) }
+        let(:developer_user) { create(:user) }
+        let(:master_group) { create(:group) }
+        let(:reporter_group) { create(:group) }
+        let(:developer_group) { create(:group) }
+
+        before do
+          create_list(:deploy_keys_project, 2, project: project_from)
+          create_list(:notification_setting, 2, source: project_from)
+          create_list(:users_star_project, 2, project: project_from)
+          project_from.project_group_links.create(group: master_group, group_access: Gitlab::Access::MASTER)
+          project_from.project_group_links.create(group: developer_group, group_access: Gitlab::Access::DEVELOPER)
+          project_from.project_group_links.create(group: reporter_group, group_access: Gitlab::Access::REPORTER)
+          project_from.add_master(master_user)
+          project_from.add_developer(developer_user)
+          project_from.add_reporter(reporter_user)
+        end
+      end
+    end
+
+    context 'forks' do
+      context 'when moving a root forked project' do
+        it 'moves the descendant forks' do
+          expect(project_from.forks.count).to eq 2
+          expect(project_to.forks.count).to eq 0
+
+          subject.execute(project_from)
+
+          expect(project_from.forks.count).to eq 0
+          expect(project_to.forks.count).to eq 2
+          expect(lvl1_forked_project_1.forked_from_project).to eq project_to
+          expect(lvl1_forked_project_1.fork_network_member.forked_from_project).to eq project_to
+          expect(lvl1_forked_project_2.forked_from_project).to eq project_to
+          expect(lvl1_forked_project_2.fork_network_member.forked_from_project).to eq project_to
+        end
+
+        it 'updates the fork network' do
+          expect(project_from.fork_network.root_project).to eq project_from
+          expect(project_from.fork_network.fork_network_members.map(&:project)).to include project_from
+
+          subject.execute(project_from)
+
+          expect(project_to.reload.fork_network.root_project).to eq project_to
+          expect(project_to.fork_network.fork_network_members.map(&:project)).not_to include project_from
+        end
+      end
+      context 'when moving a intermediate forked project' do
+        let(:project_to) { create(:project, namespace: lvl1_forked_project_1.namespace) }
+
+        it 'moves the descendant forks' do
+          expect(lvl1_forked_project_1.forks.count).to eq 2
+          expect(project_to.forks.count).to eq 0
+
+          subject.execute(lvl1_forked_project_1)
+
+          expect(lvl1_forked_project_1.forks.count).to eq 0
+          expect(project_to.forks.count).to eq 2
+          expect(lvl2_forked_project_1_1.forked_from_project).to eq project_to
+          expect(lvl2_forked_project_1_1.fork_network_member.forked_from_project).to eq project_to
+          expect(lvl2_forked_project_1_2.forked_from_project).to eq project_to
+          expect(lvl2_forked_project_1_2.fork_network_member.forked_from_project).to eq project_to
+        end
+
+        it 'moves the ascendant fork' do
+          subject.execute(lvl1_forked_project_1)
+
+          expect(project_to.reload.forked_from_project).to eq project_from
+          expect(project_to.fork_network_member.forked_from_project).to eq project_from
+        end
+
+        it 'does not update fork network' do
+          subject.execute(lvl1_forked_project_1)
+
+          expect(project_to.reload.fork_network.root_project).to eq project_from
+        end
+      end
+    end
+
+    context 'if an exception is raised' do
+      it 'rollbacks changes' do
+        updated_at = project_from.updated_at
+
+        allow(subject).to receive(:rename_project).and_raise(StandardError)
+
+        expect { subject.execute(project_from) }.to raise_error(StandardError)
+        expect(Project.find(project_from.id)).not_to be_nil
+        expect(project_from.reload.updated_at.change(usec: 0)).to eq updated_at.change(usec: 0)
+      end
+
+      it 'tries to restore the original project repositories' do
+        allow(subject).to receive(:rename_project).and_raise(StandardError)
+
+        expect(subject).to receive(:attempt_restore_repositories).with(project_from)
+
+        expect { subject.execute(project_from) }.to raise_error(StandardError)
+      end
+    end
+  end
+end