(Per-file) Overrides

Sometimes you might want to supply a custom ordering for certain constructs.

Overrides

The [[overrides]] array applies targeted rules to matching attribute paths.

Each override has a path glob and may set the partial rules (sort / first / last / [attrs]-only keys) of any construct: attrs, args, lets, inherits, lists.

Precedence

Overrides layer on top of the global construct rules (and any preset). When multiple overrides match a path, later entries in the array win for the keys they set.

Path globs

path is a glob over dot-separated attribute paths:

* matches exactly one path component;
** matches any number of components, including zero.

Examples

Leave a git alias table in its original order:

[[overrides]]
path = "**.programs.git.settings.alias"
attrs.sort = false

Put description and wantedBy first inside each systemd service:

[[overrides]]
path = "**.systemd.services.*"
attrs.first = ["description", "wantedBy"]

Sort the elements of environment.systemPackages:

[[overrides]]
path = "**.environment.systemPackages"
lists.sort = true

Restore one blank line between the inputs of a flake.nix:

[[overrides]]
path = "inputs"
attrs.blank-lines = 1

Per-file configuration

The [[files]] array applies targeted rules to matching file paths.

Each file configuration can take a full configuration using all other options (except another files).

Precedence

A matching entry layers on top of the top-level configuration, first it's preset and then any further config - when an entry sets a preset, the top-level preset is ignored entirely for that file.

As for [[overrides]], the entries' overrides are applied after the top-level ones (so the most specific entry wins).

Path globs

pattern is a glob over /-separated file paths:

* matches exactly one path component;
** matches any number of components, including zero.

By default, every pattern matches anywhere beneath the directory holding the config file. To override this, prefix the pattern with ./ following the to-be-matched pattern.

Example

This will make hello.pkg.nix use the nixpkgs-package preset while everything else keeps using nixos-module.

preset = "nixos-module"

[[files]]
pattern = "*.pkg.nix"
preset = "nixpkgs-package"

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