# JOURNAL — phase `nixenv` (Builder)

## 2026-06-17 — M1: single-source the harness runtime env

### Why this design
The phase plan §2 wants ONE definition of "what's needed to run a recipe test", referenced from
three places, so DEFECT-3 (a dep present for one path, missing for another) becomes structurally
impossible. I put the single source in `nix/modules/packages.nix` because it is the existing
"shared pkgs" overlay module already imported by both host configs — so `pkgs.ccciRuntimeTools`
and `pkgs.cc-ci-run` are reachable from every module/host without a fragile cross-module `let`.

Three overlay defs:
- `ccciPyEnv` (let-bound, internal) — `python3.withPackages [pytest playwright]`, the ONLY pyEnv now.
- `ccciRuntimeTools` (overlay attr) — the union tool set.
- `cc-ci-run` (overlay attr) — `writeShellApplication` with `runtimeInputs = [ccciPyEnv] ++ ccciRuntimeTools`.

Consumers:
- `harness.nix` → `environment.systemPackages = [ pkgs.cc-ci-run ]` (installs the entrypoint).
- `nightly-sweep.nix` → wrapper execs `cc-ci-run` (same binary the Drone pipeline runs), so pyEnv +
  tooling + PLAYWRIGHT env are identical to the Drone path by construction. Dropped: the duplicate
  pyEnv, the parallel `runtimeInputs` tool list, and the DEFECT-3 `export PATH=/run/current-system/sw/bin…`
  prepend — git-lfs/bash/util-linux/openssl now come from cc-ci-run's runtimeInputs.
- both host `configuration.nix` → `systemPackages = pkgs.ccciRuntimeTools ++ [ pkgs.openssh ]`.

### Why the union is a superset (nothing dropped)
- old cc-ci-run: `abra docker git coreutils util-linux` ⊂ set.
- old sweep: `bash abra docker git curl jq gnused gnugrep gnutar coreutils util-linux procps` ⊂ set;
  its host-PATH-derived git-lfs/openssl are now EXPLICIT in the set.
- old host PATH: `curl git jq` (+ git-lfs on hetzner only) ⊂ set; `openssh` kept as host-only add.
- pyEnv (python3+pytest+playwright) + playwright browsers (via PLAYWRIGHT_BROWSERS_PATH) preserved.
Additions vs any single prior list: `git-lfs`, `openssl` (plan §2). The `cc-ci` host GAINS git-lfs,
killing the one-off hetzner-only divergence — both host configs now byte-identical.

### Why writeShellApplication makes this work
`writeShellApplication` emits `export PATH="<runtimeInputs>:$PATH"` (confirmed on the live wrapper).
So cc-ci-run's full tool set is the PATH *prefix* regardless of caller. Under Drone the inherited
suffix is `/run/current-system/sw/bin:/run/wrappers/bin`; under the sweep it's the systemd-minimal
PATH — but the harness tools all resolve from the shared prefix either way, which is the parity the
plan wants. The host `systemPackages` reference is the belt-and-suspenders path for direct
`.drone.yml` shell-outs (`abra --version`, `docker info`) that don't go through cc-ci-run.

### buildEnv collision watch (resolved)
Worry: adding coreutils/util-linux/procps/bash/gnu* to host `systemPackages` could collide with the
NixOS base `requiredPackages`. It did not — base requiredPackages are `lowPrio`, so the normal-prio
additions override cleanly. Both `#cc-ci` and `#cc-ci-hetzner` built with no collision error.

### Note on other modules' tool lists
`backupbot/docker-prune/drone/proxy/warm-keycloak.nix` still list gnused/gnugrep/etc. in their OWN
`runtimeInputs` — those are independent reconcile-service scripts, never part of the harness/recipe
-test env, never part of the DEFECT-3 divergence. Single-sourcing is scoped to the harness env
(pyEnv + recipe-test tooling consumed by cc-ci-run / sweep / host PATH), which is now packages.nix only.

### Verification (local, dirty tree needs `?submodules=1` — `secrets/` is a submodule)
- `nixos-rebuild build --flake '.?submodules=1#cc-ci-hetzner'` → built `nixos-system-…dhmpm232…`.
- `nixos-rebuild build --flake '.?submodules=1#cc-ci'` → built OK.
- cc-ci-run store `zxlx9jnylh7la5m48bsqb1wfm5l9r0bd`; PATH carries all 15 tools incl git-lfs-3.6.1 + openssl-3.3.3.
- sweep wrapper `gh02w1kc…` execs the SAME `zxlx9j…/bin/cc-ci-run`.
- cc-ci host sw/bin now lists git-lfs + openssl (was missing git-lfs pre-refactor).
- `grep -rn withPackages nix/` → 1 hit (packages.nix:17).