Array nodes were forced read-only for every driver. A new single authority,
Core.Abstractions DriverArrayWriteSupport, says which (driver, element type)
pairs encode a whole-array write: Modbus (Coils / numeric HoldingRegisters),
S7 (Byte/Int16/UInt16/Int32/UInt32/Float32), OpcUaClient (pass-through) and
Galaxy (Boolean/Int32/Int64/Float/Double/String/DateTime). Everything else
stays read-only, so the server never advertises a write the driver refuses.
- Composer derives RawTagPlan.ArrayWritable + UnsReferenceVariable
.BackingArrayWritable at compose time (both seams, byte-parity); the
applier's one writability rule is Writable && (!IsArray || ArrayWritable)
for materialise and surgical paths, raw and UNS alike.
- ArrayWritable is on the classifier's surgical raw-tag whitelist and
mirrored on the UNS record (UnsReferenceBackingParityTests updated).
- Node manager refuses a wrong-length / non-array value on an array node
(BadTypeMismatch) and any IndexRange write (BadWriteNotSupported) inline,
before dispatch; WriteOperate/ACL gates and the revert are unchanged.
- Per-driver parity tests pin the table against the real Modbus write path,
S7 EncodeArrayBlock and Galaxy MxValueEncoder (UInt32/UInt64 excluded:
array covariance reinterprets their bits).
- Over-the-wire proof in OpcUaServer.IntegrationTests (ArrayWriteWireTests).
- ValueRank > 1 documented as out of scope by decision (docs/Uns.md).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
- AnnounceAddedNodes raises NodeAdded in the Raw realm for the existing parents of
added raw containers/tags (ComputeRawAddAnnouncements); Uns side unchanged.
- ApplyPureRemove removes UNS reference variables BEFORE the equipment subtree, so a
reference the subtree's id-prefix scope reaches no longer ratchets to a full rebuild
(03/P5). A NotSubsumed filter was not used: in production a reference NodeId is
Area/Line/Equipment/Name, outside the subtree scope, so filtering would leak it.
The matching RemoveEquipmentSubtree severing (03/S20) is in the node-manager commit.
- UnsReferenceBackingParityTests: reflection guard discovering the classifier's surgical
raw-tag whitelist and requiring a same-typed mirror field (03/U11).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty