NixOS 19.09 Backward Incompatibilities: GitLab Secrets, Networking, Corebird, Node.js, Systemd, and Kernel Releases

- The `services.gitlab` module has had its literal secret options (`services.gitlab.smtp.password`, `services.gitlab.databasePassword`, `services.gitlab.initialRootPassword`, `services.gitlab.secrets.secret`, `services.gitlab.secrets.db`, `services.gitlab.secrets.otp` and `services.gitlab.secrets.jws`) replaced by file-based versions (`services.gitlab.smtp.passwordFile`, `services.gitlab.databasePasswordFile`, `services.gitlab.initialRootPasswordFile`, `services.gitlab.secrets.secretFile`, `services.gitlab.secrets.dbFile`, `services.gitlab.secrets.otpFile` and `services.gitlab.secrets.jwsFile`). This was done so that secrets aren't stored in the world-readable nix store, but means that for each option you'll have to create a file with the same exact string, add "File" to the end of the option name, and change the definition to a string pointing to the corresponding file; e.g. `services.gitlab.databasePassword = "supersecurepassword"` becomes `services.gitlab.databasePasswordFile = "/path/to/secret_file"` where the file `secret_file` contains the string `supersecurepassword`. The state path (`services.gitlab.statePath`) now has the following restriction: no parent directory can be owned by any other user than `root` or the user specified in `services.gitlab.user`; i.e. if `services.gitlab.statePath` is set to `/var/lib/gitlab/state`, `gitlab` and all parent directories must be owned by either `root` or the user specified in `services.gitlab.user`. - The `networking.useDHCP` option is unsupported in combination with `networking.useNetworkd` in anticipation of defaulting to it. It has to be set to `false` and enabled per interface with `networking.interfaces.<name>.useDHCP = true;` - The Twitter client `corebird` has been dropped as [it is discontinued and does not work against the new Twitter API](https://www.patreon.com/posts/corebirds-future-18921328). Please use the fork `cawbird` instead which has been adapted to the API changes and is still maintained. - The `nodejs-11_x` package has been removed as it's EOLed by upstream. - Because of the systemd upgrade, systemd-timesyncd will no longer work if `system.stateVersion` is not set correctly. When upgrading from NixOS 19.03, please make sure that `system.stateVersion` is set to `"19.03"`, or lower if the installation dates back to an earlier version of NixOS. - Due to the short lifetime of non-LTS kernel releases package attributes like `linux_5_1`, `linux_5_2` and `linux_5_3` have been removed to discourage dependence on specific non-LTS kernel versions in stable NixOS releases. Going forward, versioned attributes like `linux_4_9` will exist for LTS versions only. Please use `linux_latest` or `linux_testing` if you depend on non-LTS releases. Keep in mind that `linux_latest` and `linux_testing` will change versions under the hood during the lifetime of a stable release and might include breaking changes. - Because of the systemd upgrade, some network interfaces might change their name. For details see [ upstream docs](https://www.freedesktop.org/software/systemd/man/systemd.net-naming-scheme.html#History) or [ our ticket](https://github.com/NixOS/nixpkgs/issues/71086). ## Other Notable Changes {#sec-release-19.09-notable-changes} - The `documentation` module gained an option named `documentation.nixos.includeAllModules` which makes the generated configuration.nix 5 manual page include all options from all NixOS modules included in a given `configuration.nix` configuration file. Currently, it is set to `false` by default as enabling it frequently prevents evaluation. But the plan is to eventually have it set to `true` by default. Please set it to `true` now in your `configuration.nix` and fix all the bugs it uncovers. - The `vlc` package gained support for Chromecast streaming, enabled by default. TCP port 8010 must be open for it to work, so something like `networking.firewall.allowedTCPPorts = [ 8010 ];` may be required in your configuration. Also consider enabling [ Accelerated Video Playback](https://wiki.nixos.org/wiki/Accelerated_Video_Playback) for better transcoding performance.

This section details backward incompatibilities and notable changes in NixOS 19.09, including replacing literal GitLab secret options with file-based options and introducing restrictions on the `services.gitlab.statePath`, deprecating `networking.useDHCP` in combination with `networking.useNetworkd`, dropping the Corebird Twitter client, removing the `nodejs-11_x` package, addressing systemd-timesyncd issues, removing non-LTS kernel packages, and noting potential network interface name changes. Notable changes include a new option for including all module options in the NixOS manual and Chromecast streaming support for VLC.