Module nixos 

GenerationBackend over Nix and NixOS’s switch-to-configuration.

Generation ids are Planarian’s own, kept in generations.json. They map to system store paths, because a candidate needs an id before it is in the system profile (docs/deviations.md).

Staging (§9 step 1) copies the owner’s Nix-visible files (git-tracked files with their working-tree contents, or the whole directory if it isn’t a git repository) into stage/. base_source is the NAR hash of that copy with the live override; staged_source, with the candidate override. Evaluation and build read the staged copy as a path: flake in pure-eval mode, never the owner’s live tree.

Live activation runs switch-to-configuration test in a transient unit named after the OpId (planarian-op-<txn>-<epoch>-<seq>.service), so jobs_tagged can find the work an op started even if the reply was lost.

Structs

Export

The JSON a generation exports at /etc/planarian/export.json and through config.services.planarian.export (see nix/module.nix).

ExportInput

Nixos

Registry

Constants

ACTIVATION

NIX 🔒

PARKING_GRACE 🔒

Twice §12f’s 24 h bound on parking in Built: a remembered override or a build root is never removed while a transaction that made it can still use it.

QUICK 🔒

Functions

Timestamp_now 🔒

apply_expr

The Nix function given to nix eval --apply: the export, plus the current value and highest priority of each option path the overrides touch.

closure_bytes 🔒

The total size of the union of the closures of paths.

closure_bytes_of

Sum narSize over the paths nix path-info --json lists, in either of its shapes: an object keyed by path, or an array of objects with path.

copy_file 🔒

dry_activate_failure

Why a dry activation gives no usable plan, if it does not (R10).

err 🔒

nar_hash 🔒

NAR hash of a directory.

nar_hash_of

The narHash of path in nix path-info --json output, in either of its shapes.

nix 🔒

parse_dry_activate

Parse switch-to-configuration dry-activate output.

sha 🔒

sri_sha256

A sha256-<base64> (SRI) hash as the 32 bytes it names; None for any other algorithm or a malformed value.

store_nar_hash 🔒

value_from_json 🔒

walk 🔒