# The Raw project tree (`/raw`)

v3 authors device I/O in a **Raw project tree** — a cluster-rooted, Kepware-style hierarchy
that is the single surface for driver/device/tag authoring. It is the peer of the `/uns`
unified-namespace page; the two OPC UA namespaces (`ns=Raw` / `ns=UNS`) light up in Batch 4.

```
Enterprise → Cluster → Folder(s) → Driver → Device → TagGroup(s) → Tag
```

Every node's identity is its **RawPath** (`<Folder/…>/<Driver>/<Device>/<TagGroup/…>/<Tag>`,
cluster-scoped, `/`-separated, ordinal). Names are validated as RawPath segments (no `/`, no
leading/trailing whitespace) at authoring and at the deploy gate.

## The tree

`/raw` (`GlobalRaw.razor` → `RawTree.razor`, backed by `IRawTreeService`) lazily loads each
container level on expand (unlike `/uns`, which eager-loads). Each node has a right-click
context menu **and** a `⋯` fallback (the reusable `ContextMenu` component):

| Node | Actions |
|---|---|
| Cluster | New folder · New driver |
| Folder | New folder · New driver · Rename · Delete |
| Driver | Configure · New device · Enable/Disable · Rename · Delete |
| Device | Configure (endpoint + **Test connect**) · New tag-group · Add tags ▸ · Delete |
| TagGroup | New group · Add tags ▸ · Rename · Delete |
| Tag | Edit · Delete |

Deletes are blocked while a node has children (or, for a raw tag, while a `UnsTagReference`
points at it — the error names the referencing equipment). Renames return non-blocking
**warnings**: renaming a node changes the RawPath of every historized / UNS-referenced tag
beneath it (its historian tagname / UNS projection path moves).

**A rename rebinds live data on the deploy — no node restart is needed** (Gitea #489, live-gated
2026-07-31 for both a tag rename and a device rename). The mechanism is #516's respawn: a rename
changes the merged `DriverConfig`, and `DriverSpawnPlan.Compute` stops and respawns the driver child
on any `DriverConfig` change, so the driver rebuilds against the new RawPaths and re-subscribes.
⚠️ The flip side is that **a rename reconnects the driver** — briefly dropping every tag on it, not
just the renamed one. That is the accepted cost #516 documents; it is not specific to renames.

## Endpoint → DeviceConfig (the channel/device split)

v3 moves the **connection endpoint** off the driver and onto the **Device** (`DeviceConfig`),
mirroring Kepware's channel/device split. The driver's `DriverConfig` holds protocol/channel
settings; the device's `DeviceConfig` holds host/port/endpoint. At deploy/probe time
`DriverDeviceConfigMerger` merges the device's endpoint up into the driver config, and Test
connect (inside the **Device** modal) probes that merged config. Driver forms no longer
serialize the endpoint keys, so `DeviceConfig` is the single source of truth.

**Creating a driver auto-creates an empty `Device1` (by design, #596).** Every driver needs at least one
device to hang browse and tags off, and for a single-device driver the merger treats that device's
`DeviceConfig` as the endpoint, so an empty, renamable, deletable `Device1` is the lowest-friction start
(`RawTreeService.CreateDriverAsync`; pinned by `RawTreeServiceWaveBTests`). It is not a placeholder to be
removed later.

## Authoring tags

**Add tags ▸** on a Device or TagGroup offers:

- **Manual entry** — a grid of Name / DataType / AccessLevel / WriteIdempotent / PollGroup +
  the driver-typed `TagConfig` editor per row.
- **Import/Export CSV** — a staged flow (upload → parse → **review grid** with per-row
  verdicts → commit) over an RFC-4180 parser. Columns: the common set
  (`Name, TagGroupPath, DataType, AccessLevel, WriteIdempotent, PollGroup, IsHistorized,
  HistorianTagname, IsArray, ArrayLength, Alarm.*, TagConfigJson`) plus the per-driver typed
  columns (e.g. Modbus `Region, Address, ModbusDataType, ByteOrder, …`). `TagGroupPath`
  auto-creates nested groups; typed columns win over `TagConfigJson` on conflict (flagged in
  the review grid). **Import is all-or-nothing** — any invalid row blocks the whole commit.
  Export round-trips the same shape.
- **Browse device…** — enabled per the two-tier resolution (bespoke `IDriverBrowser` →
  universal `DiscoveryDriverBrowser` when the driver's `ITagDiscovery.SupportsOnlineDiscovery`
  is true → grayed out otherwise). Multi-selected leaves become raw `Tag` rows under the
  target, with the browsed reference written into the driver-typed `TagConfig` **address
  field** (`nodeId` / `tagPath` / …), never an identity key. An opt-in "create matching
  tag-groups" toggle mirrors the browse folder nesting. The browser dials a real ephemeral
  driver against the **merged** Driver+Device config.

## What a deploy tears down (surgical deploys, 2026-08-15)

Editing a raw **tag's** attributes is no longer a fleet-wide event. A **non-alarm**
raw-tag delta whose only differences are the in-place-updatable attributes —
`Writable`, `IsHistorized`, `HistorianTagname`, `DataType`, `IsArray`, `ArrayLength`,
`ArrayWritable` (the driver's array-write capability, #610 — see
[Uns.md §Array writes](Uns.md#array-writes-610)) — and/or its set of referencing equipment is applied **in place** on the existing Raw-realm
node (`ISurgicalAddressSpaceSink.UpdateTagAttributes`), so every client subscription on
that tag and on the rest of the server survives. The same is true of **every** UNS
tag-reference change: adding, removing or re-pointing a reference used to flip the
backing raw tag to Changed (the referencing set is part of its record equality) and
rebuild the whole address space for a one-variable edit.

**Still a full rebuild**, deliberately: an **alarm-bearing** raw tag (a delta with
`Alarm != null` on either side — only a rebuild clears and re-wires the native-alarm
notifiers that fan the condition to its referencing equipment folders); an **identity**
change on a tag (`TagId`, `DriverInstanceId`, `Name`, `ParentNodeId`, realm); and any
change to a raw **container** — a Folder / Driver / Device / TagGroup **rename or
removal** — because the surgical sink has no folder-remove. The classifier is
default-closed: any field it does not explicitly whitelist, including fields added
later, still routes to a rebuild, and any surgical call returning `false` or throwing
ratchets back to one.

**Mirror repair.** A raw-side historian or shape edit also reaches every UNS reference
mirroring the tag: the reference record carries the backing tag's historian/shape, so
the edit emits a coincident UNS-reference delta. Identity-preserving repairs update the
mirror **in place** (its MonitoredItems survive); a re-point or effective-name change
removes and recreates **that one mirror node**. See [`Uns.md`](Uns.md) and
[`plans/2026-08-15-surgical-deploys.md`](plans/2026-08-15-surgical-deploys.md).

A surgically added raw container/tag is **announced** (Gitea #599): `AnnounceAddedNodes`
raises a `GeneralModelChangeEvent(NodeAdded)` in the **Raw** realm for each distinct
existing parent of the added nodes (a parent that is itself new in the same deploy is
skipped — its own parent is announced, and a re-browse there finds the whole new subtree;
a new top-level folder announces itself). UNS-side adds announce in the Uns realm as
before. Until #599 raw adds were materialised but never announced, so model-aware clients
only saw them on their next browse — invisible while every add still forced a rebuild.

Removing an equipment that holds UNS references is also surgical: the references are
removed (terminal Bad, then `RemoveVariableNode`, which severs the backing raw node's
inverse `Organizes` edge) **before** the equipment subtree, and the subtree removal severs
the same edge for anything it reaches itself (archreview 03/P5 + 03/S20).

## The `Calculation` driver

Signal-level calculated tags are ordinary raw tags bound to a `Calculation` driver
(`DriverTypeNames.Calculation`), computed by C# scripts that read other tags' live values via
`ctx.GetTag("<RawPath>")`. See `docs/plans/2026-07-15-calculation-driver-mini-design.md` for
the full design. Highlights:

- ⚠️ **Correction (2026-07-28): the "auto-created default `Engine` device" below never shipped.**
  `"Engine"` has zero occurrences in `src/`, and nothing special-cases `Calculation` at device
  creation — author the device like any other. Per-tag `TagConfig` is
  `{ "scriptId": "…", "changeTriggered": true, "timerIntervalMs": 5000 }`.
- The host feeds dependency values via the new `IDependencyConsumer` capability + a
  `DependencyConsumerMuxAdapter` on the per-node dependency mux; calc-of-calc chains work
  because a calc output re-enters the mux. The driver rebuilds its tag/dependency table on
  every redeploy (`ReinitializeAsync`) and re-registers its refs after the delta applies.
- **Deploy gates** (`DraftValidator`): `scriptId` existence, and a hard **cycle gate**
  (`DependencyGraph.DetectCycles` over calc→calc edges; cross-driver refs are terminal) that
  rejects an A→B→A oscillation loop naming the members. Compile is not hard-gated (VirtualTag
  parity); a runtime compile/throw/timeout lands as Bad quality + a `script-logs` entry.

## Quality: a raw tag's node when its driver stops communicating

A raw tag's node — and every UNS mirror of it — goes **`BadNoCommunication` with its last value
retained** when the owning driver is declared comms-lost, and clears when the driver re-publishes. It is
never cleared by the server on reconnect: recovery is a value, never an assumption. The rule and the
seams that implement it are stated once in
[`docs/DriverLifecycle.md` §"The quality contract"](DriverLifecycle.md#the-quality-contract).

Calc tags authored here inherit the same rule from their inputs — see
[`docs/drivers/Calculation.md` §"Input quality"](drivers/Calculation.md#input-quality).

## Retirement note

The routed `/clusters/{id}/drivers` driver-authoring flow (`DriverTypePicker`,
`DriverEditRouter`, the 8 per-type `*DriverPage` shells, and the per-cluster Drivers list) is
**retired** — authoring lives in `/raw`. The extracted driver/device **form bodies** live on
inside the `/raw` modals. The `DriverType` dispatch maps (`TagConfigEditorMap`,
`TagConfigValidator`, `EquipmentTagConfigInspector`) are keyed off the single-source-of-truth
`DriverTypeNames` constants (fixing the historical `TwinCat`/`Focas` drift).