Add migration to rename all namespaces with forbidden name

This is based on a migration in https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2073

Rename forbidden child namespaces

db/post_migrate/20170403121055_rename_forbidden_root_namespaces.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RenameForbiddenRootNamespaces < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  include Gitlab::ShellAdapter
+  disable_ddl_transaction!
+
+  class Namespace < ActiveRecord::Base
+    self.table_name = 'namespaces'
+    belongs_to :parent, class_name: "Namespace"
+    has_one :route, as: :source, autosave: true
+    has_many :children, class_name: "Namespace", foreign_key: :parent_id
+    has_many :projects
+    belongs_to :owner, class_name: "User"
+
+    def full_path
+      if route && route.path.present?
+        @full_path ||= route.path
+      else
+        update_route if persisted?
+
+        build_full_path
+      end
+    end
+
+    def build_full_path
+      if parent && path
+        parent.full_path + '/' + path
+      else
+        path
+      end
+    end
+
+    def update_route
+      prepare_route
+      route.save
+    end
+
+    def prepare_route
+      route || build_route(source: self)
+      route.path = build_full_path
+      route.name = build_full_name
+      @full_path = nil
+      @full_name = nil
+    end
+
+    def build_full_name
+      if parent && name
+        parent.human_name + ' / ' + name
+      else
+        name
+      end
+    end
+
+    def human_name
+      owner&.name
+    end
+  end
+
+  class Route < ActiveRecord::Base
+    self.table_name = 'routes'
+    belongs_to :source, polymorphic: true
+
+    validates :source, presence: true
+
+    validates :path,
+              length: { within: 1..255 },
+              presence: true,
+              uniqueness: { case_sensitive: false }
+  end
+
+  class Project < ActiveRecord::Base
+    self.table_name = 'projects'
+
+    def repository_storage_path
+      Gitlab.config.repositories.storages[repository_storage]['path']
+    end
+  end
+
+  DOWNTIME = false
+  DISALLOWED_PATHS = %w[
+    api
+    autocomplete
+    search
+    member
+    explore
+    uploads
+    import
+    notification_settings
+    abuse_reports
+    invites
+    help
+    koding
+    health_check
+    jwt
+    oauth
+    sent_notifications
+  ]
+
+  def up
+    DISALLOWED_PATHS.each do |path|
+      say "Renaming namespaces called #{path}"
+      forbidden_namespaces_with_path(path).each do |namespace|
+        rename_namespace(namespace)
+      end
+    end
+  end
+
+  def down
+    # nothing to do
+  end
+
+  def rename_namespace(namespace)
+    old_path = namespace.path
+    old_full_path = namespace.full_path
+    # Only remove the last occurrence of the path name to get the parent namespace path
+    namespace_path = remove_last_occurrence(old_full_path, old_path)
+    new_path = rename_path(namespace_path, old_path)
+    new_full_path = if namespace_path.present?
+                      File.join(namespace_path, new_path)
+                    else
+                      new_path
+                    end
+
+    Namespace.where(id: namespace).update_all(path: new_path) # skips callbacks & validations
+
+    replace_statement = replace_sql(Route.arel_table[:path], old_full_path, new_full_path)
+
+    update_column_in_batches(:routes, :path, replace_statement)  do |table, query|
+      query.where(Route.arel_table[:path].matches("#{old_full_path}%"))
+    end
+
+    clear_cache_for_namespace(namespace)
+
+    # tasks here are based on `Namespace#move_dir`
+    move_repositories(namespace, old_full_path, new_full_path)
+    move_namespace_folders(uploads_dir, old_full_path, new_full_path) if file_storage?
+    move_namespace_folders(pages_dir, old_full_path, new_full_path)
+  end
+
+  # This will replace the first occurance of a string in a column with
+  # the replacement
+  # On postgresql we can use `regexp_replace` for that.
+  # On mysql we remove the pattern from the beginning of the string, and
+  # concatenate the remaining part tot the replacement.
+  def replace_sql(column, pattern, replacement)
+    if Gitlab::Database.mysql?
+      substr = Arel::Nodes::NamedFunction.new("substring", [column, pattern.to_s.size + 1])
+      concat = Arel::Nodes::NamedFunction.new("concat", [Arel::Nodes::Quoted.new(replacement.to_s), substr])
+      Arel::Nodes::SqlLiteral.new(concat.to_sql)
+    else
+      replace = Arel::Nodes::NamedFunction.new("regexp_replace", [column, Arel::Nodes::Quoted.new(pattern.to_s), Arel::Nodes::Quoted.new(replacement.to_s)])
+      Arel::Nodes::SqlLiteral.new(replace.to_sql)
+    end
+  end
+
+  def remove_last_occurrence(string, pattern)
+    string.reverse.sub(pattern.reverse, "").reverse
+  end
+
+  def move_namespace_folders(directory, old_relative_path, new_relative_path)
+    old_path = File.join(directory, old_relative_path)
+    return unless File.directory?(old_path)
+
+    new_path = File.join(directory, new_relative_path)
+    FileUtils.mv(old_path, new_path)
+  end
+
+  def move_repositories(namespace, old_full_path, new_full_path)
+    repo_paths_for_namespace(namespace).each do |repository_storage_path|
+      # Ensure old directory exists before moving it
+      gitlab_shell.add_namespace(repository_storage_path, old_full_path)
+
+      unless gitlab_shell.mv_namespace(repository_storage_path, old_full_path, new_full_path)
+        say "Exception moving path #{repository_storage_path} from #{old_full_path} to #{new_full_path}"
+      end
+    end
+  end
+
+  def rename_path(namespace_path, path_was)
+    counter = 0
+    path = "#{path_was}#{counter}"
+
+    while route_exists?(File.join(namespace_path, path))
+      counter += 1
+      path = "#{path_was}#{counter}"
+    end
+
+    path
+  end
+
+  def route_exists?(full_path)
+    Route.where(Route.arel_table[:path].matches(full_path)).any?
+  end
+
+  def forbidden_namespaces_with_path(name)
+    Namespace.where(arel_table[:path].matches(name).and(arel_table[:parent_id].eq(nil)))
+  end
+
+  def clear_cache_for_namespace(namespace)
+    project_ids = project_ids_for_namespace(namespace)
+    scopes = { "Project" => { id: project_ids },
+               "Issue" => { project_id: project_ids },
+               "MergeRequest" => { target_project_id: project_ids },
+               "Note" => { project_id: project_ids } }
+
+    ClearDatabaseCacheWorker.perform_async(scopes)
+  rescue => e
+    Rails.logger.error ["Couldn't clear the markdown cache: #{e.message}", e.backtrace.join("\n")].join("\n")
+  end
+
+  def project_ids_for_namespace(namespace)
+    namespace_ids = child_ids_for_parent(namespace, ids: [namespace.id])
+    namespace_or_children = Project.arel_table[:namespace_id].in(namespace_ids)
+    Project.unscoped.where(namespace_or_children).pluck(:id)
+  end
+
+  # This won't scale to huge trees, but it should do for a handful of namespaces
+  def child_ids_for_parent(namespace, ids: [])
+    namespace.children.each do |child|
+      ids << child.id
+      child_ids_for_parent(child, ids: ids) if child.children.any?
+    end
+    ids
+  end
+
+  def repo_paths_for_namespace(namespace)
+    namespace.projects.unscoped.select('distinct(repository_storage)').to_a.map(&:repository_storage_path)
+  end
+
+  def uploads_dir
+    File.join(Rails.root, "public", "uploads")
+  end
+
+  def pages_dir
+    Settings.pages.path
+  end
+
+  def file_storage?
+    CarrierWave::Uploader::Base.storage == CarrierWave::Storage::File
+  end
+
+  def arel_table
+    Namespace.arel_table
+  end
+end

db/post_migrate/20170404152317_rename_forbidden_child_namespaces.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RenameForbiddenChildNamespaces < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  include Gitlab::ShellAdapter
+  disable_ddl_transaction!
+
+  class Namespace < ActiveRecord::Base
+    self.table_name = 'namespaces'
+    belongs_to :parent, class_name: "Namespace"
+    has_one :route, as: :source, autosave: true
+    has_many :children, class_name: "Namespace", foreign_key: :parent_id
+    has_many :projects
+    belongs_to :owner, class_name: "User"
+
+    def full_path
+      if route && route.path.present?
+        @full_path ||= route.path
+      else
+        update_route if persisted?
+
+        build_full_path
+      end
+    end
+
+    def build_full_path
+      if parent && path
+        parent.full_path + '/' + path
+      else
+        path
+      end
+    end
+
+    def update_route
+      prepare_route
+      route.save
+    end
+
+    def prepare_route
+      route || build_route(source: self)
+      route.path = build_full_path
+      route.name = build_full_name
+      @full_path = nil
+      @full_name = nil
+    end
+
+    def build_full_name
+      if parent && name
+        parent.human_name + ' / ' + name
+      else
+        name
+      end
+    end
+
+    def human_name
+      owner&.name
+    end
+  end
+
+  class Route < ActiveRecord::Base
+    self.table_name = 'routes'
+    belongs_to :source, polymorphic: true
+
+    validates :source, presence: true
+
+    validates :path,
+              length: { within: 1..255 },
+              presence: true,
+              uniqueness: { case_sensitive: false }
+  end
+
+  class Project < ActiveRecord::Base
+    self.table_name = 'projects'
+
+    def repository_storage_path
+      Gitlab.config.repositories.storages[repository_storage]['path']
+    end
+  end
+
+  DOWNTIME = false
+  DISALLOWED_PATHS = %w[info git-upload-pack
+                        git-receive-pack gitlab-lfs autocomplete_sources
+                        templates avatar commit pages compare network snippets
+                        services mattermost deploy_keys forks import merge_requests
+                        branches merged_branches tags protected_branches variables
+                        triggers pipelines environments cycle_analytics builds
+                        hooks container_registry milestones labels issues
+                        project_members group_links notes noteable boards todos
+                        uploads runners runner_projects settings repository
+                        transfer remove_fork archive unarchive housekeeping
+                        toggle_star preview_markdown export remove_export
+                        generate_new_export download_export activity
+                        new_issue_address]
+
+  def up
+    DISALLOWED_PATHS.each do |path|
+      say "Renaming namespaces called #{path}"
+      forbidden_namespaces_with_path(path).each do |namespace|
+        rename_namespace(namespace)
+      end
+    end
+  end
+
+  def down
+    # nothing to do
+  end
+
+  def rename_namespace(namespace)
+    old_path = namespace.path
+    old_full_path = namespace.full_path
+    # Only remove the last occurrence of the path name to get the parent namespace path
+    namespace_path = remove_last_occurrence(old_full_path, old_path)
+    new_path = rename_path(namespace_path, old_path)
+    new_full_path = if namespace_path.present?
+                      File.join(namespace_path, new_path)
+                    else
+                      new_path
+                    end
+
+    Namespace.where(id: namespace).update_all(path: new_path) # skips callbacks & validations
+
+    replace_statement = replace_sql(Route.arel_table[:path], old_full_path, new_full_path)
+
+    update_column_in_batches(:routes, :path, replace_statement)  do |table, query|
+      query.where(Route.arel_table[:path].matches("#{old_full_path}%"))
+    end
+
+    clear_cache_for_namespace(namespace)
+
+    # tasks here are based on `Namespace#move_dir`
+    move_repositories(namespace, old_full_path, new_full_path)
+    move_namespace_folders(uploads_dir, old_full_path, new_full_path) if file_storage?
+    move_namespace_folders(pages_dir, old_full_path, new_full_path)
+  end
+
+  # This will replace the first occurance of a string in a column with
+  # the replacement
+  # On postgresql we can use `regexp_replace` for that.
+  # On mysql we remove the pattern from the beginning of the string, and
+  # concatenate the remaining part tot the replacement.
+  def replace_sql(column, pattern, replacement)
+    if Gitlab::Database.mysql?
+      substr = Arel::Nodes::NamedFunction.new("substring", [column, pattern.to_s.size + 1])
+      concat = Arel::Nodes::NamedFunction.new("concat", [Arel::Nodes::Quoted.new(replacement.to_s), substr])
+      Arel::Nodes::SqlLiteral.new(concat.to_sql)
+    else
+      replace = Arel::Nodes::NamedFunction.new("regexp_replace", [column, Arel::Nodes::Quoted.new(pattern.to_s), Arel::Nodes::Quoted.new(replacement.to_s)])
+      Arel::Nodes::SqlLiteral.new(replace.to_sql)
+    end
+  end
+
+  def remove_last_occurrence(string, pattern)
+    string.reverse.sub(pattern.reverse, "").reverse
+  end
+
+  def move_namespace_folders(directory, old_relative_path, new_relative_path)
+    old_path = File.join(directory, old_relative_path)
+    return unless File.directory?(old_path)
+
+    new_path = File.join(directory, new_relative_path)
+    FileUtils.mv(old_path, new_path)
+  end
+
+  def move_repositories(namespace, old_full_path, new_full_path)
+    repo_paths_for_namespace(namespace).each do |repository_storage_path|
+      # Ensure old directory exists before moving it
+      gitlab_shell.add_namespace(repository_storage_path, old_full_path)
+
+      unless gitlab_shell.mv_namespace(repository_storage_path, old_full_path, new_full_path)
+        say "Exception moving path #{repository_storage_path} from #{old_full_path} to #{new_full_path}"
+      end
+    end
+  end
+
+  def rename_path(namespace_path, path_was)
+    counter = 0
+    path = "#{path_was}#{counter}"
+
+    while route_exists?(File.join(namespace_path, path))
+      counter += 1
+      path = "#{path_was}#{counter}"
+    end
+
+    path
+  end
+
+  def route_exists?(full_path)
+    Route.where(Route.arel_table[:path].matches(full_path)).any?
+  end
+
+  def forbidden_namespaces_with_path(path)
+    Namespace.where(arel_table[:parent_id].eq(nil).not).where(arel_table[:path].matches(path))
+  end
+
+  def clear_cache_for_namespace(namespace)
+    project_ids = project_ids_for_namespace(namespace)
+    scopes = { "Project" => { id: project_ids },
+               "Issue" => { project_id: project_ids },
+               "MergeRequest" => { target_project_id: project_ids },
+               "Note" => { project_id: project_ids } }
+
+    ClearDatabaseCacheWorker.perform_async(scopes)
+  rescue => e
+    Rails.logger.error ["Couldn't clear the markdown cache: #{e.message}", e.backtrace.join("\n")].join("\n")
+  end
+
+  def project_ids_for_namespace(namespace)
+    namespace_ids = child_ids_for_parent(namespace, ids: [namespace.id])
+    namespace_or_children = Project.arel_table[:namespace_id].in(namespace_ids)
+    Project.unscoped.where(namespace_or_children).pluck(:id)
+  end
+
+  # This won't scale to huge trees, but it should do for a handful of namespaces
+  def child_ids_for_parent(namespace, ids: [])
+    namespace.children.each do |child|
+      ids << child.id
+      child_ids_for_parent(child, ids: ids) if child.children.any?
+    end
+    ids
+  end
+
+  def repo_paths_for_namespace(namespace)
+    namespace.projects.unscoped.select('distinct(repository_storage)').to_a.map(&:repository_storage_path)
+  end
+
+  def uploads_dir
+    File.join(Rails.root, "public", "uploads")
+  end
+
+  def pages_dir
+    Settings.pages.path
+  end
+
+  def file_storage?
+    CarrierWave::Uploader::Base.storage == CarrierWave::Storage::File
+  end
+
+  def arel_table
+    Namespace.arel_table
+  end
+end

db/post_migrate/20170405111106_rename_wildcard_project_names.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RenameWildcardProjectNames < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  include Gitlab::ShellAdapter
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+  KNOWN_PATHS = %w[info git-upload-pack
+                   git-receive-pack gitlab-lfs autocomplete_sources
+                   templates avatar commit pages compare network snippets
+                   services mattermost deploy_keys forks import merge_requests
+                   branches merged_branches tags protected_branches variables
+                   triggers pipelines environments cycle_analytics builds
+                   hooks container_registry milestones labels issues
+                   project_members group_links notes noteable boards todos
+                   uploads runners runner_projects settings repository
+                   transfer remove_fork archive unarchive housekeeping
+                   toggle_star preview_markdown export remove_export
+                   generate_new_export download_export activity
+                   new_issue_address].freeze
+
+  def up
+    reserved_projects.find_in_batches(batch_size: 100) do |slice|
+      rename_projects(slice)
+    end
+  end
+
+  def down
+    # nothing to do here
+  end
+
+  private
+
+  def reserved_projects
+    Project.unscoped.
+      includes(:namespace).
+      where('EXISTS (SELECT 1 FROM namespaces WHERE projects.namespace_id = namespaces.id)').
+      where('projects.path' => KNOWN_PATHS)
+  end
+
+  def route_exists?(full_path)
+    quoted_path = ActiveRecord::Base.connection.quote_string(full_path.downcase)
+
+    ActiveRecord::Base.connection.
+      select_all("SELECT id, path FROM routes WHERE lower(path) = '#{quoted_path}'").present?
+  end
+
+  # Adds number to the end of the path that is not taken by other route
+  def rename_path(namespace_path, path_was)
+    counter = 0
+    path = "#{path_was}#{counter}"
+
+    while route_exists?("#{namespace_path}/#{path}")
+      counter += 1
+      path = "#{path_was}#{counter}"
+    end
+
+    path
+  end
+
+  def rename_projects(projects)
+    projects.each do |project|
+      id = project.id
+      path_was = project.path
+      namespace_path = project.namespace.path
+      path = rename_path(namespace_path, path_was)
+
+      begin
+        # Because project path update is quite complex operation we can't safely
+        # copy-paste all code from GitLab. As exception we use Rails code here
+        project.rename_repo if rename_project_row(project, path)
+      rescue Exception => e # rubocop: disable Lint/RescueException
+        Rails.logger.error "Exception when renaming project #{id}: #{e.message}"
+      end
+    end
+  end
+
+  def rename_project_row(project, path)
+    project.respond_to?(:update_attributes) &&
+      project.update_attributes(path: path) &&
+      project.respond_to?(:rename_repo)
+  end
+end

spec/migrations/rename_forbidden_child_namespaces_spec.rb

+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20170404152317_rename_forbidden_child_namespaces.rb')
+
+describe RenameForbiddenChildNamespaces, truncate: true do
+  let(:migration) { described_class.new }
+  let(:test_dir) { File.join(Rails.root, 'tmp', 'tests', 'rename_namespaces_test') }
+  let(:uploads_dir) { File.join(test_dir, 'public', 'uploads') }
+  let(:forbidden_namespace) do
+    namespace = build(:group, path: 'info')
+    namespace.parent = create(:group, path: 'parent')
+    namespace.save(validate: false)
+    namespace
+  end
+
+  before do
+    FileUtils.remove_dir(test_dir) if File.directory?(test_dir)
+    FileUtils.mkdir_p(uploads_dir)
+    FileUtils.remove_dir(TestEnv.repos_path) if File.directory?(TestEnv.repos_path)
+    allow(migration).to receive(:say)
+    allow(migration).to receive(:uploads_dir).and_return(uploads_dir)
+  end
+
+  describe '#forbidden_namespaces_with_path' do
+    let(:other_namespace) { create(:group, path: 'info') }
+    before do
+      forbidden_namespace
+      other_namespace
+    end
+
+    it 'includes namespaces called with path `info`' do
+      expect(migration.forbidden_namespaces_with_path('info').map(&:id)).to contain_exactly(forbidden_namespace.id)
+    end
+  end
+
+  describe '#up' do
+    before do
+      forbidden_namespace
+    end
+
+    it 'renames namespaces called info' do
+      migration.up
+
+      expect(forbidden_namespace.reload.path).to eq('info0')
+    end
+
+    it 'renames the route to the namespace' do
+      migration.up
+
+      expect(forbidden_namespace.reload.full_path).to eq('parent/info0')
+    end
+
+    it 'renames the route for projects of the namespace' do
+      project = create(:project, path: 'project-path', namespace: forbidden_namespace)
+
+      migration.up
+
+      expect(project.route.reload.path).to eq('parent/info0/project-path')
+    end
+
+    it 'moves the the repository for a project in the namespace' do
+      create(:project, namespace: forbidden_namespace, path: 'info-project')
+      expected_repo = File.join(TestEnv.repos_path, 'parent/info0', 'info-project.git')
+
+      migration.up
+
+      expect(File.directory?(expected_repo)).to be(true)
+    end
+
+    it 'moves the uploads for the namespace' do
+      allow(migration).to receive(:move_namespace_folders).with(Settings.pages.path, 'parent/info', 'parent/info0')
+      expect(migration).to receive(:move_namespace_folders).with(uploads_dir, 'parent/info', 'parent/info0')
+
+      migration.up
+    end
+
+    it 'moves the pages for the namespace' do
+      allow(migration).to receive(:move_namespace_folders).with(uploads_dir, 'parent/info', 'parent/info0')
+      expect(migration).to receive(:move_namespace_folders).with(Settings.pages.path, 'parent/info', 'parent/info0')
+
+      migration.up
+    end
+
+    it 'clears the markdown cache for projects in the forbidden namespace' do
+      project = create(:project, namespace: forbidden_namespace)
+      scopes = { 'Project' => { id: [project.id] },
+                 'Issue' => { project_id: [project.id] },
+                 'MergeRequest' => { target_project_id: [project.id] },
+                 'Note' => { project_id: [project.id] } }
+
+      expect(ClearDatabaseCacheWorker).to receive(:perform_async).with(scopes)
+
+      migration.up
+    end
+
+    context 'forbidden namespace -> subgroup -> info0 project' do
+      it 'updates the route of the project correctly' do
+        subgroup = create(:group, path: 'subgroup', parent: forbidden_namespace)
+        project = create(:project, path: 'info0', namespace: subgroup)
+
+        migration.up
+
+        expect(project.route.reload.path).to eq('parent/info0/subgroup/info0')
+      end
+    end
+  end
+
+  describe '#move_repositories' do
+    let(:namespace) { create(:group, name: 'hello-group') }
+    it 'moves a project for a namespace' do
+      create(:project, namespace: namespace, path: 'hello-project')
+      expected_path = File.join(TestEnv.repos_path, 'bye-group', 'hello-project.git')
+
+      migration.move_repositories(namespace, 'hello-group', 'bye-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+
+    it 'moves a namespace in a subdirectory correctly' do
+      child_namespace = create(:group, name: 'sub-group', parent: namespace)
+      create(:project, namespace: child_namespace, path: 'hello-project')
+
+      expected_path = File.join(TestEnv.repos_path, 'hello-group', 'renamed-sub-group', 'hello-project.git')
+
+      migration.move_repositories(child_namespace, 'hello-group/sub-group', 'hello-group/renamed-sub-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+
+    it 'moves a parent namespace with subdirectories' do
+      child_namespace = create(:group, name: 'sub-group', parent: namespace)
+      create(:project, namespace: child_namespace, path: 'hello-project')
+      expected_path = File.join(TestEnv.repos_path, 'renamed-group', 'sub-group', 'hello-project.git')
+
+      migration.move_repositories(child_namespace, 'hello-group', 'renamed-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+  end
+
+  describe '#move_namespace_folders' do
+    it 'moves a namespace with files' do
+      source = File.join(uploads_dir, 'parent-group', 'sub-group')
+      FileUtils.mkdir_p(source)
+      destination = File.join(uploads_dir, 'parent-group', 'moved-group')
+      FileUtils.touch(File.join(source, 'test.txt'))
+      expected_file = File.join(destination, 'test.txt')
+
+      migration.move_namespace_folders(uploads_dir, File.join('parent-group', 'sub-group'), File.join('parent-group', 'moved-group'))
+
+      expect(File.exist?(expected_file)).to be(true)
+    end
+
+    it 'moves a parent namespace uploads' do
+      source = File.join(uploads_dir, 'parent-group', 'sub-group')
+      FileUtils.mkdir_p(source)
+      destination = File.join(uploads_dir, 'moved-parent', 'sub-group')
+      FileUtils.touch(File.join(source, 'test.txt'))
+      expected_file = File.join(destination, 'test.txt')
+
+      migration.move_namespace_folders(uploads_dir, 'parent-group', 'moved-parent')
+
+      expect(File.exist?(expected_file)).to be(true)
+    end
+  end
+
+  describe '#child_ids_for_parent' do
+    it 'collects child ids for all levels' do
+      parent = create(:namespace)
+      first_child = create(:namespace, parent: parent)
+      second_child = create(:namespace, parent: parent)
+      third_child = create(:namespace, parent: second_child)
+      all_ids = [parent.id, first_child.id, second_child.id, third_child.id]
+
+      collected_ids = migration.child_ids_for_parent(parent, ids: [parent.id])
+
+      expect(collected_ids).to contain_exactly(*all_ids)
+    end
+  end
+
+  describe '#remove_last_ocurrence' do
+    it 'removes only the last occurance of a string' do
+      input = 'this/is/info/namespace/with/info'
+
+      expect(migration.remove_last_occurrence(input, 'info')).to eq('this/is/info/namespace/with/')
+    end
+  end
+end

spec/migrations/rename_forbidden_root_namespaces_spec.rb

+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20170403121055_rename_forbidden_root_namespaces.rb')
+
+describe RenameForbiddenRootNamespaces, truncate: true do
+  let(:migration) { described_class.new }
+  let(:test_dir) { File.join(Rails.root, 'tmp', 'tests', 'rename_namespaces_test') }
+  let(:uploads_dir) { File.join(test_dir, 'public', 'uploads') }
+  let(:forbidden_namespace) do
+    namespace = build(:namespace, path: 'api')
+    namespace.save(validate: false)
+    namespace
+  end
+
+  before do
+    FileUtils.remove_dir(test_dir) if File.directory?(test_dir)
+    FileUtils.mkdir_p(uploads_dir)
+    FileUtils.remove_dir(TestEnv.repos_path) if File.directory?(TestEnv.repos_path)
+    allow(migration).to receive(:say)
+    allow(migration).to receive(:uploads_dir).and_return(uploads_dir)
+  end
+
+  describe '#forbidden_namespaces_with_path' do
+    before do
+      forbidden_namespace
+    end
+
+    it 'includes namespaces called with path `api`' do
+      expect(migration.forbidden_namespaces_with_path('api').map(&:id)).to include(forbidden_namespace.id)
+    end
+  end
+
+  describe '#up' do
+    before do
+      forbidden_namespace
+    end
+
+    it 'renames namespaces called api' do
+      migration.up
+
+      expect(forbidden_namespace.reload.path).to eq('api0')
+    end
+
+    it 'renames the route to the namespace' do
+      migration.up
+
+      expect(forbidden_namespace.reload.full_path).to eq('api0')
+    end
+
+    it 'renames the route for projects of the namespace' do
+      project = create(:project, path: 'project-path', namespace: forbidden_namespace)
+
+      migration.up
+
+      expect(project.route.reload.path).to eq('api0/project-path')
+    end
+
+    it 'moves the the repository for a project in the namespace' do
+      create(:project, namespace: forbidden_namespace, path: 'api-project')
+      expected_repo = File.join(TestEnv.repos_path, 'api0', 'api-project.git')
+
+      migration.up
+
+      expect(File.directory?(expected_repo)).to be(true)
+    end
+
+    it 'moves the uploads for the namespace' do
+      allow(migration).to receive(:move_namespace_folders).with(Settings.pages.path, 'api', 'api0')
+      expect(migration).to receive(:move_namespace_folders).with(uploads_dir, 'api', 'api0')
+
+      migration.up
+    end
+
+    it 'moves the pages for the namespace' do
+      allow(migration).to receive(:move_namespace_folders).with(uploads_dir, 'api', 'api0')
+      expect(migration).to receive(:move_namespace_folders).with(Settings.pages.path, 'api', 'api0')
+
+      migration.up
+    end
+
+    it 'clears the markdown cache for projects in the forbidden namespace' do
+      project = create(:project, namespace: forbidden_namespace)
+      scopes = { 'Project' => { id: [project.id] },
+                 'Issue' => { project_id: [project.id] },
+                 'MergeRequest' => { target_project_id: [project.id] },
+                 'Note' => { project_id: [project.id] } }
+
+      expect(ClearDatabaseCacheWorker).to receive(:perform_async).with(scopes)
+
+      migration.up
+    end
+
+    context 'forbidden namespace -> subgroup -> api0 project' do
+      it 'updates the route of the project correctly' do
+        subgroup = create(:group, path: 'subgroup', parent: forbidden_namespace)
+        project = create(:project, path: 'api0', namespace: subgroup)
+
+        migration.up
+
+        expect(project.route.reload.path).to eq('api0/subgroup/api0')
+      end
+    end
+
+    context 'for a sub-namespace' do
+      before do
+        forbidden_namespace.parent = create(:namespace, path: 'parent')
+        forbidden_namespace.save(validate: false)
+      end
+
+      it "doesn't rename child-namespace paths" do
+        migration.up
+
+        expect(forbidden_namespace.reload.full_path).to eq('parent/api')
+      end
+    end
+  end
+
+  describe '#move_repositories' do
+    let(:namespace) { create(:group, name: 'hello-group') }
+    it 'moves a project for a namespace' do
+      create(:project, namespace: namespace, path: 'hello-project')
+      expected_path = File.join(TestEnv.repos_path, 'bye-group', 'hello-project.git')
+
+      migration.move_repositories(namespace, 'hello-group', 'bye-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+
+    it 'moves a namespace in a subdirectory correctly' do
+      child_namespace = create(:group, name: 'sub-group', parent: namespace)
+      create(:project, namespace: child_namespace, path: 'hello-project')
+
+      expected_path = File.join(TestEnv.repos_path, 'hello-group', 'renamed-sub-group', 'hello-project.git')
+
+      migration.move_repositories(child_namespace, 'hello-group/sub-group', 'hello-group/renamed-sub-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+
+    it 'moves a parent namespace with subdirectories' do
+      child_namespace = create(:group, name: 'sub-group', parent: namespace)
+      create(:project, namespace: child_namespace, path: 'hello-project')
+      expected_path = File.join(TestEnv.repos_path, 'renamed-group', 'sub-group', 'hello-project.git')
+
+      migration.move_repositories(child_namespace, 'hello-group', 'renamed-group')
+
+      expect(File.directory?(expected_path)).to be(true)
+    end
+  end
+
+  describe '#move_namespace_folders' do
+    it 'moves a namespace with files' do
+      source = File.join(uploads_dir, 'parent-group', 'sub-group')
+      FileUtils.mkdir_p(source)
+      destination = File.join(uploads_dir, 'parent-group', 'moved-group')
+      FileUtils.touch(File.join(source, 'test.txt'))
+      expected_file = File.join(destination, 'test.txt')
+
+      migration.move_namespace_folders(uploads_dir, File.join('parent-group', 'sub-group'), File.join('parent-group', 'moved-group'))
+
+      expect(File.exist?(expected_file)).to be(true)
+    end
+
+    it 'moves a parent namespace uploads' do
+      source = File.join(uploads_dir, 'parent-group', 'sub-group')
+      FileUtils.mkdir_p(source)
+      destination = File.join(uploads_dir, 'moved-parent', 'sub-group')
+      FileUtils.touch(File.join(source, 'test.txt'))
+      expected_file = File.join(destination, 'test.txt')
+
+      migration.move_namespace_folders(uploads_dir, 'parent-group', 'moved-parent')
+
+      expect(File.exist?(expected_file)).to be(true)
+    end
+  end
+
+  describe '#child_ids_for_parent' do
+    it 'collects child ids for all levels' do
+      parent = create(:namespace)
+      first_child = create(:namespace, parent: parent)
+      second_child = create(:namespace, parent: parent)
+      third_child = create(:namespace, parent: second_child)
+      all_ids = [parent.id, first_child.id, second_child.id, third_child.id]
+
+      collected_ids = migration.child_ids_for_parent(parent, ids: [parent.id])
+
+      expect(collected_ids).to contain_exactly(*all_ids)
+    end
+  end
+
+  describe '#remove_last_ocurrence' do
+    it 'removes only the last occurance of a string' do
+      input = 'this/is/api/namespace/with/api'
+
+      expect(migration.remove_last_occurrence(input, 'api')).to eq('this/is/api/namespace/with/')
+    end
+  end
+end