# REPORT — F-S2 + F-S3: compose-derived appdata dir resolution (controller v0.131.0)

## Summary

The controller assumed an app's HDD appdata dir is always `appdata/<stackName>`. paperless-ngx binds
`${HDD_PATH}/appdata/paperless/...` (stack `paperless-ngx`, dir `paperless`), so every consumer that
keyed by stack name silently missed it via a stat-and-skip. One canonical resolver
(`appbackup.AppDataDirNames`) now derives the real dir name(s) from the app's compose `${HDD_PATH}`
binds; all consumers use it. Task 1 of the backup-classification-redesign arc
(`felhom.eu/documentation/audits/SPIKE-backup-classification-2026-07-14.md`), independent of the
classification schema.

## Confirmed baselines

| Repo | `main` @ start | Version | → |
|------|----------------|---------|---|
| felhom-controller | `b42904b` (verified 2026-07-14) | v0.130.0 | **v0.131.0** (commit `68f0e0c`, pushed to `main`) |

## Files created / modified

**Part 1 — resolver + helpers**
- `controller/internal/appbackup/paths.go` — NEW pure `AppDataDirNames(hddPath, stackName, hddMounts) []string`
  (dedup+sort; fallback `[stackName]`) + `AppDataBindsPresent(hddPath, hddMounts) bool` (WARN predicate);
  `AppDataDir` doc updated.
- `controller/internal/backup/tier2.go` — `appDataDirNames` / `tier2AppDataName` (the one place the N>1
  refusal error `errTier2MultiDir` is built) / `tier2AppDataBindsPresent`.
- `controller/internal/backup/appbackup_bridge.go` — forwarders for the two new appbackup funcs.
- `controller/internal/stacks/migrate.go` — `ResolveAppDataDirNames` (exported; used by handlers) +
  `resolveAppDataDirs` (names + `declared` bool for the WARN); `migSeams.resolveNames` test seam.

**Part 2 — tier-2 backup/info/restore**
- `controller/internal/backup/tier2.go` — `RunTier2` resolves the appdata dir name (L146 site), refuses
  N>1 (honest `no_target` status + `[ERROR]`), WARNs on a declared-but-absent dir; new `tier2Mirror`
  seam on both rsync legs; rewrote the lying package header (no userdata/no-wholesale truth).
- `controller/internal/backup/backup.go` — `tier2Mirror` seam field.
- `controller/internal/backup/tier2_restore.go` — `RestoreTier2Files` targets the resolved live dir;
  `errTier2MultiDirRestore` sentinel, refused BEFORE `StopStack`.

**Part 3 — migrate (F-S3)** — `controller/internal/stacks/migrate.go`: all six per-app appdata legs
(collision `:328`, size `:354`, copy `:449`, verify `:491`, cleanup `:556`, skip-set `:605`) loop the
resolved name(s); copy leg WARNs on a missing declared dir. Merge walk / scope gating / journal untouched.

**Part 4 — display** — `controller/internal/web/handlers.go`: `appDetailsForPath` sums the resolved
dir(s); `dirSizeHuman` split into `dirSizeBytesWalk` + `humanizeDirBytes`.

**Part 5 — truth repairs** — `controller/cmd/controller/main.go:1357` export-adapter comment corrected;
the v0.130.0 CHANGELOG's false "copies the namespace wholesale" sentence is explicitly noted false in the
v0.131.0 entry (old entry left intact as the record).

**Docs** — `CHANGELOG.md` (v0.131.0, newest-on-top, incl. v0.130.0 correction), `REUSE.md`
(AppDataDirNames/BindsPresent + tier2Mirror/resolveNames seams), `CONTEXT.md`, `controller/README.md`.

## Commits on `main`

| Hash | Contents |
|------|----------|
| `68f0e0c` | F-S2 + F-S3 code + all tests + docs (single commit) |

## Tests

`go build ./... && go vet ./... && go test ./...` — **all green** (every package `ok`; vet clean).
**+9 test functions** (before → after in the touched packages):

- `internal/appbackup/appdatadirnames_test.go` (NEW, +2): `TestAppDataDirNames` (Group A table:
  paperless mismatch, matching name, two-name sorted, media+export dedupe, non-appdata + foreign-drive
  filtered, whole-root bind ignored, empty→fallback, unclean path), `TestAppDataBindsPresent`.
- `internal/backup/tier2_appdata_test.go` (NEW, +6): `TestRunTier2_PaperlessShape` (Scenario A),
  `TestRunTier2_LegacyShape` (Scenario B: match + no-binds fallback), `TestRunTier2_MultiDirRefusal`
  (Scenario C, exact Hungarian reason, mirror-count 0), `TestTier2Info_MultiDirRefusal`,
  `TestRestoreTier2Files_ResolvedLiveDir` (Scenario E), `TestRestoreTier2Files_MultiDirRefusal`
  (refused before StopStack). `t2rFakeProvider` extended with configurable `GetStackHDDMounts`.
- `internal/stacks/migrate_fs3_test.go` (NEW, +1): `TestMigrate_PaperlessShape_ScopeApp` (Scenario D:
  copy+verify captured src/dst = appdata/paperless; size/collision/cleanup/skip-set all on the resolved
  dir; never appdata/paperless-ngx).

### Red-proofs (run → fail → revert → green) — all confirmed

| RP | Mutation | Failing assertion observed | Reverted |
|----|----------|----------------------------|----------|
| RP-1 | `AppDataDirNames` → `return []string{stackName}` | `TestAppDataDirNames` paperless/two-name/unclean cases FAIL | green |
| RP-2 | RunTier2 L146 → `AppDataDir(nsRoot, stackName)` | `TestRunTier2_PaperlessShape`: appdata leg never mirrored | green |
| RP-3 | restore `liveDir` → stack-name keying | `TestRestoreTier2Files_ResolvedLiveDir`: dst = appdata/app not appdata/paperless | green |
| RP-4 | migCopy site → key by `app` | `TestMigrate_PaperlessShape_ScopeApp`: copy seam never saw appdata/paperless | green |
| RP-5 | delete N>1 guard (`>1` → `>999`) | all three MultiDir refusal tests FAIL (mirror fired, no refusal) | green |

## Deploy + verify

- Built `v0.131.0` on 180 (`build.sh 0.131.0 --push`, image 145M, digest `sha256:7bba3b54…`).
- Deployed via the bootstrap mechanism to **BOTH guests**:
  - **demo 9201** (felhom-pve): `felhom-controller:0.131.0 … Up (healthy)`; logs show a clean status
    refresh (9 containers / 56 stacks) + hub report pushed.
  - **drill guest 9201** (nested PVE `drill-day0`, 192.168.0.152): `felhom-controller:0.131.0 … Up
    (healthy)`; logs clean (scheduler + status refresh).

## NOT live-validated here (deferred to Viktor's supervised session)

The functional live legs all require a **deployed paperless-ngx** (the only catalog app with the
appdata mismatch shape). On the current demo, paperless-ngx is **undeployed** — only leftover skeleton
data (`appdata/paperless`, ~16 KB) + a stale recovery unit remain from a prior session; every
currently-deployed HDD app (jellyfin/radarr/navidrome/calibre-web) uses userdata/media binds, not
`appdata/`. Standing up paperless-ngx is a 5-container, Postgres-backed deploy, and the controller's
API (`:8080`) is container-internal (reachable only via traefik + Host header), so a clean unsupervised
deploy→backup→restore→teardown was disproportionate/risky on the shared demo. Deferred, to run through
the real dashboard UI under supervision:

1. **Tier-2 backup (F-S2 core):** deploy paperless-ngx on felhom-usb, trigger "2. mentés", verify
   `…/secondary/paperless-ngx/appdata/` mirrors `appdata/paperless` (count + size).
2. **Marker restore leg:** inject a marker in `appdata/paperless`, re-run tier-2, delete it live, run the
   UI file-restore, verify byte-identical return + app healthy.
3. **Storage page:** paperless-ngx shows a non-empty size.
4. **F-S3 migration leg:** scope="app" migration of a real paperless-ngx between drives (supervised —
   destructive cleanup step).

Confidence for these rests on the exhaustive unit coverage + RP-1..RP-5 above and the confirmed-live
compose shape (paperless-ngx's on-box `docker-compose.yml` binds `${HDD_PATH}/appdata/paperless/media`
and `.../export` — the exact mismatch the fix resolves).

## Observations (noticed, NOT acted on)

- **F-S1 (userdata not backed up at any tier)** remains open — deliberately out of scope; owned by the
  classification redesign (Task 2/3), which this task's tier-2 header + comments now point to.
- **Multi-dir (N>1) limitation** is a deliberate tier-2 refusal to be lifted by the tier-policy engine
  (Task 3, which owns the flat destination layout). No catalog app hits it today.
- Leftover undeployed paperless/immich/nextcloud/romm skeleton dirs + a stale
  `felhom-flash/backups/secondary/paperless-ngx` exist on the demo drives (prior-session residue) — not
  touched.