Merge pull request #268871 from tweag/release-notes-lib

- `networking.networkmanager.firewallBackend` was removed as NixOS is now using iptables-nftables-compat even when using iptables, therefore Networkmanager now uses the nftables backend unconditionally.

- [`lib.lists.foldl'`](https://nixos.org/manual/nixpkgs/stable#function-library-lib.lists.foldl-prime) now always evaluates the initial accumulator argument first.

  If you depend on the lazier behavior, consider using [`lib.lists.foldl`](https://nixos.org/manual/nixpkgs/stable#function-library-lib.lists.foldl) or [`builtins.foldl'`](https://nixos.org/manual/nix/stable/language/builtins.html#builtins-foldl') instead.

- [`lib.attrsets.foldlAttrs`](https://nixos.org/manual/nixpkgs/stable#function-library-lib.attrsets.foldlAttrs) now always evaluates the initial accumulator argument first.

- `rome` was removed because it is no longer maintained and is succeeded by `biome`.

- The `prometheus-knot-exporter` was migrated to a version maintained by CZ.NIC. Various metric names have changed, so checking existing rules is recommended.

- Docker now defaults to 24, as 20.10 is stopping to receive security updates and bug fixes after [December 10, 2023](https://github.com/moby/moby/discussions/45104).

- There is a new NixOS option when writing NixOS tests `testing.initrdBackdoor`, that enables `backdoor.service` in initrd. Requires `boot.initrd.systemd.enable` to be enabled. Boot will pause in stage 1 at `initrd.target`, and will listen for commands from the `Machine` python interface, just like stage 2 normally does. This enables commands to be sent to test and debug stage 1. Use `machine.switch_root()` to leave stage 1 and proceed to stage 2.

## Nixpkgs library changes {#sec-release-23.11-lib}

### Breaking changes {#sec-release-23.11-lib-breaking}

- [`lib.lists.foldl'`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.foldl-prime)

  now always evaluates the initial accumulator argument first.

  If you depend on the lazier behavior, consider using [`lib.lists.foldl`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.foldl)

  or [`builtins.foldl'`](https://nixos.org/manual/nix/stable/language/builtins.html#builtins-foldl') instead.

- [`lib.attrsets.foldlAttrs`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.attrsets.foldlAttrs)

  now always evaluates the initial accumulator argument first.

- Now that the internal NixOS transition to Markdown documentation is complete,

  `lib.options.literalDocBook` has been removed after deprecation in 22.11.

- `lib.types.string` is now fully deprecated and gives a warning when used.

### Additions and improvements {#sec-release-23.11-lib-additions-improvements}

- [`lib.fileset`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-fileset):

  A new sub-library to select local files to use for sources,

  designed to be easy and safe to use.

  This aims to be a replacement for `lib.sources`-based filtering.

  To learn more about it, see [the tutorial](https://nix.dev/tutorials/file-sets).

- [`lib.gvariant`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-gvariant):

  A partial and basic implementation of GVariant formatted strings.

  See [GVariant Format Strings](https://docs.gtk.org/glib/gvariant-format-strings.html) for details.

  :::{.warning}

  This API is not considered fully stable and it might therefore

  change in backwards incompatible ways without prior notice.

  :::

- [`lib.asserts`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-asserts): New function:

  [`assertEachOneOf`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.asserts.assertEachOneOf).

- [`lib.attrsets`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-attrsets): New function:

  [`attrsToList`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.attrsets.attrsToList).

- [`lib.customisation`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-customisation): New function:

  [`makeScopeWithSplicing'`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.customisation.makeScopeWithSplicing-prime).

- [`lib.fixedPoints`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-fixedPoints): Documentation improvements for

  [`lib.fixedPoints.fix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.fixedPoints.fix).

- `lib.generators`: New functions:

  [`mkDconfKeyValue`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.generators.mkDconfKeyValue),

  [`toDconfINI`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.generators.toDconfINI).

  `lib.generators.toKeyValue` now supports the `indent` attribute in its first argument.

- [`lib.lists`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-lists): New functions:

  [`findFirstIndex`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.findFirstIndex),

  [`hasPrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.hasPrefix),

  [`removePrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.removePrefix),

  [`commonPrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.commonPrefix),

  [`allUnique`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.allUnique).

  Documentation improvements for

  [`lib.lists.foldl'`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.foldl-prime).

- [`lib.meta`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-meta): Documentation of functions now gets rendered

- [`lib.path`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-path): New functions:

  [`hasPrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.path.hasPrefix),

  [`removePrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.path.removePrefix),

  [`splitRoot`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.path.splitRoot),

  [`subpath.components`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.path.subpath.components).

- [`lib.strings`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-strings): New functions:

  [`replicate`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.strings.replicate),

  [`cmakeOptionType`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.strings.cmakeOptionType),

  [`cmakeBool`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.strings.cmakeBool),

  [`cmakeFeature`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.strings.cmakeFeature).

- [`lib.trivial`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-trivial): New function:

  [`mirrorFunctionArgs`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.trivial.mirrorFunctionArgs).

- `lib.systems`: New function:

  [`equals`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.systems.equals).

- [`lib.options`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-options): Improved documentation for

  [`mkPackageOption`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.options.mkPackageOption).

  [`mkPackageOption`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.options.mkPackageOption).

  now also supports the `pkgsText` attribute.

Module system:

- Options in the `options` module argument now have the `declarationPositions` attribute

  containing the position where the option was declared:

  ```

  $ nix repl -f '<nixpkgs/nixos>'

  [...]

  nix-repl> :p options.environment.systemPackages.declarationPositions

  [ {

    column = 7;

    file = "/nix/store/vm9zf9wvfd628cchj0hdij1g4hzjrcz9-source/nixos/modules/config/system-path.nix";

    line = 62;

  } ]

  ```

  Not to be confused with `definitionsWithLocations`, which is the same but for option _definitions_.

- Improved error message for option declarations missing `mkOption`

### Deprecations {#sec-release-23.11-lib-deprecations}

- `lib.meta.getExe pkg` (also available as `lib.getExe`) now gives a warning if `pkg.meta.mainProgram` is not set,

  but it continues to default to the derivation name.

  Nixpkgs accepts PRs that set `meta.mainProgram` on packages where it makes sense.

  Use `lib.getExe' pkg "some-command"` to avoid the warning and/or select a different executable.