P7.6C #446: IEC 61850 report continuity evidence (SqNum/segmentation/EntryID)

[masarray]

Exact HEAD CI & artifact status — 2026-10-08

• 9/9 triggered GitHub Actions workflows SUCCESS on exact head 397d7836e5b071d4f3c6b375f9c51879c58eeb48.
• Merge Execution Guard: 1,393 passed, 0 failed, 0 skipped ARSAS.Tests.
• Main Windows x64 native build, publish + smoke: SUCCESS; portable single EXE.
• Smart Discovery field-capture Windows build: SUCCESS; field-capture portable artifact.
• Earlier branch attempts had a return type compile error (List<string> ?? string[]) and an intermediate optimization dangling variable. Those were corrected; only this exact HEAD is fully CI-qualified. No hidden skip/relaxation of tests.
• Status: CodeCommitted, CIPassed, ArtifactAvailable. Physical continuity qualification / GI-reset-EntryID-reconnect replay stress remain pending. Draft / not merge-ready / not released.

Baseline and ownership

Stacked on P7.6B PR #483 at exact 5a05ab2187e04aaf70106ef5c59a0c625503aaef, physically tested on separate Discovery IP/Open SCD sessions with matching semantic fingerprint and independent BRCB/URCB report traffic. ARIEC61850 remains immutably pinned at 352c81e6a798635c6addcee0683235ca87ad416d.

Scope: consumer-side report continuity evidence only. Files owned in this draft: Services/Iec61850MonitorRuntime.cs (diagnostic integration only), Services/Iec61850ReportContinuityInspector.cs (pure, per-stream state machine), new tests/ARSAS.Tests/ReportContinuityP76CTests.cs. No engine modifications, RCB configuration, GI writes, process updates, static DataSet selection, polling, command controls or reordering/replay heuristics.

Standard context / field motivation

IEC 61850-7-2 buffered reporting report SqNum is a 16-bit unsigned counter per BRCB with increment and maximum rollover; first report after enabling is sequence 0. Segmented reports share SqNum and start SubSqNum 0, then increment for continuation; BufOvfl indicates possible loss, while EntryID is opaque BRCB resync identity and ConfRev changes require schema revalidation. A later GI report or different EntryID cannot be treated as proof of harmless SqNum reset.

Operator field pair shows observed early Rpt_ind01: 4→1 (Open SCD) and Rpt_ind02: 3→1 (Discovery). Those remain explicit unverified discontinuity warnings. No claim of lost SOE entries or harmless reset is made absent RptEna lifecycle/EntryID/GI evidence.

Implementation

• Fix old naive IsExpectedReportSequence which accepted any current==0 as rollover; now only 65535→0 is recognized as 16-bit wrap.
• Separate association/exact RCB stream continuity state; first observed nonzero sequence does not imply packet loss; distinguish duplicate/replay, backward/reset/replay, forward gap without asserting actual event loss.
• Segmented report integrity: first SubSqNum 0, continuation same SqNum and next sub number, missing completion/sequence and inconsistent optional field diagnostics.
• BufOvfl, ConfRev drift and opaque EntryID presence/change are recorded as evidence, not value-plane changes. No timestamp/quality rewriting, no forced GI, no cyclic MMS polling fallback.
• Existing report-stream state lifecycle remains cleared on monitoring restart, disconnect and reconnect. No stale-session continuity attribution.
• Synthetic tests cover standard wrap, invalid 4→0, physical 4→1 / 3→1, out-of-range metadata, GI-unproven states, segmentation, BufOvfl+ConfRev and per-session isolation.

Gates

CodeCommitted; CI pending and physical continuity stress test still PhysicalPending. Maintain draft, do not merge/release until exact-head CI and field continuity scenarios are qualified. Parent #446. Other workstreams should coordinate file ownership before editing Services/Iec61850MonitorRuntime.cs.