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Author SHA1 Message Date
romanett 87c35b84b6 Fix Opc.Ua.Client audit findings (security fallback, reconnect, subscriptions, redundancy, browse, files, WebApi) (#4572)
## Summary

Fixes the findings of a bug audit of `Opc.Ua.Client` and
`Opc.Ua.Client.ComplexTypes`, done on master plus #4516 (now merged).

- **Audit:** 82 findings across 12 areas, each checked against the OPC
UA specification. Final severities: 2 High, 37 Medium, 43 Low.
- **Fixes:** 76 fixed, 4 partial, 2 skipped (see [Not
fixed](#not-fixed--partial)).
- **Review:** a follow-up review of the fixes found 15 more defects in
them, all fixed here.
- **Tests:** every fix has a regression test, except a few races that
cannot be reproduced deterministically; the commit messages say which.

The finding IDs (`L<area>-<n>` for the audit, `G<n>` for the review)
appear in the commit titles.

## Behaviour and user-facing changes

### Security and endpoint selection
- **Reconnect no longer drops to weaker security (L3-1, High).** When
the server rejects the configured security policy or mode during
reconnect, `SessionReconnectHandler` no longer switches to whatever
endpoint the server advertises, None included. It only picks an endpoint
at least as strong as the configured one, judged by a locally computed
security level. The server-advertised `SecurityLevel` is not trusted. If
nothing qualifies, reconnect fails with the original error (new log
event `SessionReconnectHandler + 13`) and keeps retrying with the
original settings.
- **`CoreClientUtils.SelectEndpoint(useSecurity: true)` never returns a
SecurityMode None endpoint over opc.tcp (L9-9, High).** It now returns
`null` when no secure endpoint matches.
- When the discovery URL is `https`/`opc.https`, an HTTPS endpoint with
SecurityMode None is still accepted as a last resort, because TLS
protects it (Part 6 §7.4.1) (G17).
  - Endpoints with SecurityMode `Invalid` no longer count as secure.
- `GlobalDiscoveryServerClient` and `ServerPushConfigurationClient` now
throw `BadSecurityPolicyRejected` when no secure endpoint matches,
instead of passing `null` on. The ConsoleReferenceClient sample reports
this with a clear error.
- **No Bearer/Basic credentials over `http://` (L12-2).**
`WebApiClient.Create` and WebApi channel open/reconnect reject them with
`BadSecurityChecksFailed`. The public `WebApiClient(HttpClient, …)`
constructor also rejects them when the client's `BaseAddress` is not
https, and every send checks the address it actually goes to (covers a
`BaseAddress` set later).

### Session, keep-alive and identity
- **Faster detection of a silent server (L1-1).** The keep-alive Read is
now bounded by its `TimeoutHint` (2 × `KeepAliveInterval`), which is
what Part 4 §7.32 says the client should do. It then fails with
`BadNoCommunication`, so reconnect starts after about 2 ×
`KeepAliveInterval` instead of `OperationTimeout` (120 s by default).
- **Operations fail fast during a channel-manager recovery (L1-2, G9).**
`UpdateIdentityAsync`, `TransferSubscriptionsAsync` and
`ReactivateSubscriptionsAsync` fail with `BadSecureChannelClosed`
(retryable) instead of deadlocking. This covers the operation holding
the reconnect lock and any queued behind it.
- **Closing or disposing from a handler no longer waits on itself (L1-3,
G5, G6).**
- `Session` and `ManagedSession` Close/Dispose from a Notification
handler no longer wait 30 s for their own background drain.
- Disposing a `ManagedSession` from a keep-alive `PublishStatusChanged`
handler no longer deadlocks.
- Tasks spawned by a handler no longer count as "the handler" (the owner
marker is scoped to the work item).
- **Switching to an ECC user-token policy takes two ActivateSession
calls (L1-4, G4).** This follows Part 6 §6.8.2 (fetch the ephemeral key,
then activate).
- If the server returns no key, the switch fails with
`BadSecurityPolicyRejected`.
- If the second activation is rejected, the old identity stays on the
override policy with the key just fetched. Restoring the old key was
tried: against the reference server the next reconnect then failed to
decrypt the identity token.
- **`ManagedSession.ConfiguredEndpoint` follows failover (L2-6).** It
now reports the inner session's endpoint, so it changes after a failover
or network-path rotation.
- **An explicit identity update replaces the identity provider (L2-7).**
`ManagedSession.UpdateSessionAsync(identity)` stops the provider's
refresh loop and drops the provider for good. If the update fails, the
loop is restarted.
- **Reconnect waits for in-flight calls on a healthy channel (L2-3,
G8a).** Reconnect/failover on a healthy channel (certificate or
trust-list change, manual reconnect) waits for in-flight service calls.
The wait is bounded (max(`KeepAliveInterval`, 1 s)) only once the
channel is unhealthy (keep-alive stopped, channel not Ready), so a dead
channel no longer holds recovery for `OperationTimeout`.
- **Smaller fixes:**
- Restore reads the server certificate as a chain; this failed on macOS
(L1-5).
  - Session recovery can no longer run twice at once (L1-6).
  - Identity expiries more than 49.7 days out no longer throw (L2-2).
- Keep-alive reconnect suppression is recalculated on a lease swap
(L2-4).

### Reconnect state machine and reverse connect
- **⚠ `MaxTotalReconnectTime = 0` now means "no time limit" (L3-7).
Reviewer decision needed.** Before, 0 disabled reconnect entirely.
Negative values other than `Timeout.InfiniteTimeSpan` now throw
`ArgumentOutOfRangeException` when the state machine is constructed;
before, they crashed the worker. The XML docs of
`ReconnectPolicy`/`ReconnectPolicyOptions` are updated. If 0 should keep
meaning "no reconnect", this is a one-line revert.
- **A close racing the end of the reconnect budget is no longer lost
(L3-4).** It goes through the normal close instead of switching to
failover.
- **The "reconnect worker" marker covers one step only (L2-1).** It
lasts for a single connect/reconnect/failover/close step. Keep-alive,
publish and identity loops started in a step no longer count as the
worker afterwards.
- **Reverse-connect strategies `Undefined` and `Any` alone are removed
after the first callback (L8-1).** This matches the documentation;
before, they behaved like `Always`.
- **`AddEndpoint` for a URL that is already added disposes the replaced
listener (L8-2).**

### Service calls
- **Batched calls clean up after a failed later batch (L3-2).** When a
later batch of
`Browse`/`BrowseNext`/`HistoryRead`/`CreateMonitoredItems` fails, the
continuation points and monitored items created by earlier batches are
released or deleted before the exception is rethrown. This adds one
request. `AddNodes`/`RegisterNodes` are not undone.
- **Batched diagnostic infos point at the right strings (L3-3).** The
string-table indexes are rebased when diagnostics are padded.
- **`ReadBytesAsync` rejects oversized responses (L3-5).** It throws
`BadUnknownResponse` when the server returns more bytes than requested,
and `BadEncodingLimitsExceeded` beyond `int` range.
- **`ReadByteStringInChunksAsync` handles an unknown server limit
(L3-6).** When the server's `MaxByteStringLength` is 0 (absent) or
larger than `int`, it falls back to the client's
`MessageContext.MaxByteStringLength`. It throws only when both are
unknown.

### Browse and NodeCache
- **Empty browse pages with a continuation point are followed (L9-1,
L9-4, L9-5, G16).** Part 4 §5.9.2.1 allows a server to return an empty
page with a continuation point, so browsing keeps following it. After 10
consecutive empty rounds it gives up with `BadNoData` and releases the
continuation point.
- `BrowseAsync(NodeId)` now throws instead of silently returning a
truncated list.
  - `BrowseStreamAsync` yields a `BadNoData` result for that node.
- The same cap, through one shared helper, now also protects
`RoleManagementClient.ListRolesAsync` and the FileSystem
enumerate/empty-check loops.
- **Continuation points are released on failure (L9-3).**
`BrowseAsync(NodeId)` releases them on any exception, and
`BrowseStreamAsync` releases all points of the current page when the
consumer stops early.
- **NodeCache lookups propagate cancellation (L9-6, L9-8).**
`FindAsync`, `IsKnownAsync`, `FetchNodeAsync`,
`FindReferenceTypeNameAsync`, the reference-table fill and the
type-hierarchy search now let `OperationCanceledException` through.
Before, a cancelled lookup looked like "node does not exist".
- **A NodeClass mismatch fails only that node (L9-7).** It returns
`BadNodeClassInvalid` for that node instead of throwing
`KeyNotFoundException` for the whole batch.
- **Smaller fixes:**
- `MaxNodesPerBrowse` ≥ 2^31 no longer breaks the managed browse (L9-2).
  - Null discovery URLs are skipped (L9-10).
  - `ModelChangeTracker` no longer cancels a joined start (L9-11).
- **Log changes:** `BrowserContinuationPointExistsButBrowse` (Browser +
0) was removed, and `BrowserServerReturnedEmptyReferencesBut` now
includes the round count.

### Subscriptions (default engine)
- **Recovery after a transfer delivers each message exactly once (L5-1,
G22).** Messages already dispatched are acknowledged instead of
republished and delivered again. Messages whose earlier republish failed
are now republished and delivered, with the Republish flag and after
newer messages, instead of being acknowledged and lost.
- **A keep-alive that proves a gap triggers republish at once (L5-5,
G23).** The dedup mark moves only past messages that were actually
recovered, so a failed republish is retried by the next data message.
- **Item changes that fail are retried with backoff (L5-3).** They are
retried on the next apply pass after the state manager's 250 ms–5 s
backoff, instead of six times back to back. The six attempts now span
about 13 s.
- **Extreme revised intervals no longer throw (L5-4, L6-1).** Very large
or NaN intervals and counts revised by the server are capped (NaN falls
back to the requested value). Before, the overflow could stop every
publish worker.
- **`SetTriggeringAsync` from a callback no longer hangs (L5-7, G21).**
While the subscription is deleted, recreated or disposed, it returns
`BadOperationAbandoned`. A cancelled reset no longer makes later calls
fail.
- **Publish responses for unknown subscription ids (L6-3, L6-4, G20).**
The client no longer re-sends acknowledgements the server already
processed. An unknown id seen while a creation is pending is left alone
instead of being deleted.
- **Smaller fixes:**
- A null and an empty `IndexRange` are treated as equal, and restored
snapshots use `null` (L5-6).
  - A failed partition attach during restore is rolled back (L6-2).
- `StreamingSubscription` throws `ObjectDisposedException` after dispose
(L6-6).

### Subscriptions (classic `Subscription`)
- **Republish no longer abandons other missing messages (L7-1).** A
Republish response no longer overwrites `AvailableSequenceNumbers`, so
other missing messages are not given up while the server still holds
them.
- **Late copies are no longer delivered twice (L7-2).** Copies of
already-processed sequence numbers are ignored, and creating a new
server subscription resets the sequence state.
- **Disposing from a keep-alive handler no longer deadlocks (L7-3).**
`Dispose()` from a keep-alive `PublishStatusChanged` handler can return
while that callback is still finishing.
- **Transfer of a restored subscription (L7-4, G27).**
  - It succeeds even when some saved items were never created.
- The server subscription is deleted only when this session's own
TransferSubscriptions just moved it and adoption failed definitively
(item count mismatch or a non-transient status). Transient errors and
`ReactivateSubscriptionsAsync` never delete it.
  - The public `Subscription.TransferAsync` never deletes.
- **Smaller fixes:**
  - Cloned items keep their triggering links (L7-5).
  - `CreateAsync` clears stale server ids (L7-6).
- A `Good_SubscriptionTransferred` for the client's own transfer is
ignored (L7-7).
- An item removed while its create is in flight is deleted afterwards
(L7-8).
- The publish timeout for very long keep-alives no longer overflows
(L7-9).
  - A negative `MaxMessageCount` is handled (L7-10).
  - `LastMessage` tolerates a wrong notification type (L7-11).
  - Pending acks exactly 2^31 away no longer throw (L4-1).
- **Log changes:** new log events `Subscription + 68..70`.

### Redundancy
- **Warm/Hot demotion (L4-2, G1, G3).**
- Without token reuse, the demoted leader closes its session and
reconnects as a fresh standby.
- With token reuse, it abandons the shared server session locally,
without CloseSession, so the new leader can reactivate it and keep its
subscriptions. This uses the new internal methods
`ManagedSession.AbandonServerSessionAsync` and
`Session.AbandonServerSession`.
- `RoleChanged(false)` is now raised before the standby connect and no
longer depends on it, so `CurrentSession` can briefly be `null`.
- Exceptions from `RoleChanged` handlers are logged and do not stop the
teardown.
- **Promotion (L4-3, G2).** A promoted standby that adopts the leader's
session first closes its own server session. A retried promotion keeps
the session it already adopted.
- **Client failover takeover (L4-4, partial).** Subscriptions the backup
prepared in advance (not yet created, `TransferId` set to the active
client's id) are moved through the session's own transfer and keep
publishing. `docs/HighAvailability.md` is updated.
- **`ShouldFailover` through the interface (L4-6).** Calling it through
`IServerRedundancyHandler` no longer fails over away from a server that
is still Healthy.

### Fluent / dependency injection
- **Shared DI session (L10-5).** The shared session from `AddClient` is
reconnected after a caller disposes it, and is disposed with the
container. After that the connect delegate throws
`ObjectDisposedException`.
- **New public API:
`ManagedSessionBuilder.WithServerRedundancyOptions(ServerRedundancyOptions)`
(L10-6).** This is additive. The `Session.ServerRedundancy` options are
now actually applied.
- **`AddDiscoveryAndConnect` rewrites the advertised address (L10-7).**
It replaces the host and port the server advertises with those of the
discovery URL (Part 4 §5.6.2.1, NAT/containers), and prefers endpoints
with the same scheme.

### State machines and role management
- **`GetSubStateMachineAsync` returns the instance's own sub-state
machine (L10-1).** Before, it returned the type's placeholder.
- **`WaitForStateAsync` reports failures with OPC UA status codes
(L10-2).** It throws `BadNotFound` when `CurrentState/Id` cannot be
resolved, and `BadInvalidState` when observation ends without reaching
the state. Before, both surfaced as `OperationCanceledException`.
- **`RoleManagementClient.ListRolesAsync` pages correctly (L10-3).** It
follows continuation points, releases them on any failure, and throws on
a Bad browse status instead of returning an empty list.
- **Role properties are read into the right fields (L10-4).** Properties
whose namespace cannot be resolved are skipped instead of shifting the
other values.

### File system, temporary files and alias names
- **Path escaping (L11-8, G12).**
- Path segments escape `:` and `/` with `&`, and `&` itself as `&&`
before those characters or at the end of a name.
- `Format` and `Parse` round-trip all names. Typed input ending in `&/`
now reads the slash as part of the name.
- A segment without a namespace prefix also matches a namespace-0 child
when nothing matches in the parent's namespace.
- **Stale path cache (L11-1).** When a cached lookup fails,
`GetInfoAsync` retries once from the server. `ExistsAsync` and
`GetFileAsync` report "not found" instead of throwing.
- **`GenerateFileForReadAsync` waits for the file (L11-2).** It waits
until the file-generation state machine reaches ReadTransfer (`Idle`
counts as not started yet), and throws `IOException` if it reports
Error. The wait is bounded only by the caller's token.
- **Non-recursive delete refuses hidden children (L11-3).** It refuses
when the directory holds children that the subtype options hide from
enumeration. Before, the server deleted them all.
- **Alias names (L11-5, L11-6, L11-7).**
- `BadMethodInvalid` maps to `NotSupportedException` for all alias
calls, so `UseVerbose` falls back to `FindAlias`.
  - A duplicate alias name resolves to all its targets.
- If the refresh strategy fails to start, the resolver logs a warning
and keeps working without automatic invalidation. New log event block
`AliasNameResolver = 560`.
- **Null profile entries (L11-4).** Null `ServerProfileArray` entries no
longer crash `GetConformanceInfoAsync`.

### WebApi transport
- **Failures come back as `ServiceResultException` (L12-1).**
  - A timeout becomes `BadRequestTimeout`.
- HTTP 429/503 becomes `BadServerTooBusy` with the Retry-After hint, on
every target framework. `WebApiClient` checks the status itself (reusing
`HttpsTransportChannel.CreateServerTooBusyException`), so callers of
`WebApiClient` also get a `ServiceResultException` instead of an
`HttpRequestException` for these two statuses (G15).
  - An IO error becomes `BadNotConnected`.
- **Timeouts (L12-1, G14).**
- `OperationTimeout` applies to each request. When `RequestTimeout` is
unset, HttpClient's 100 s default no longer cuts off long Publish
requests.
- The GetEndpoints call at open is bounded by `OperationTimeout`, and
cancelling the open now throws.
- **Core change:** `HttpsTransportChannel.MapRequestFailure` went from
private to internal so the WebApi channel can reuse it.

### ComplexTypes
- **Out-of-range union selector (L12-3).** A union whose SwitchField is
larger than its field count now fails with `BadDecodingError` when
decoded and `BadEncodingError` when encoded (Part 6 §5.2.8).
- **Verbose JSON unions (L12-4).** They now decode their selected field
instead of `null`.

## Not fixed / partial
- **L2-5 (skipped):** an identity provider combined with a
caller-supplied reverse connection still can't connect to an
undiscovered endpoint. Fixing it means choosing the identity after
CreateSession, a design change.
- **L4-5 (skipped):** the one-time KeyCredential token needs a fresh
token on each reactivation. Today reactivation fails and the client
falls back to a new session.
- **L4-4 (partial):** only subscriptions the backup prepared in advance
survive a takeover.
- **L3-2 (partial):** `AddNodes`/`RegisterNodes` batches are not rolled
back.
- **L2-3 (partial):** service calls still hold the session lock for
their whole round trip.
- **Known from the review, not fixed here:**
  - G7: the batch cleanup request can't be cancelled.
- G11: the DI session's close at host shutdown never reaches the server,
and a closed session keeps being handed out.
- G13: a file renamed by another client is still found under its old
path.
  - G25: a clone-based transfer doesn't mark the original subscriptions.
  - G27b: the transfer item check matches by count, not by ID.
- **Outside this PR:** the reference server ignores `ECDHPolicyUri` on
ActivateSession (`SessionSecurityPolicyHelper`), which breaks Part 6
§6.8.2. As a result, the L1-4 two-step ECC switch ends in
`BadSecurityPolicyRejected` against our own server.

## Testing
All suites on net10.0, on the branch before the master merge. Every
suite had 0 failures:

| Suite | Passed | Skipped |
|---|---|---|
| Opc.Ua.Client.Tests | 2698 | 0 |
| Opc.Ua.Redundancy.Client.Tests | 134 | 0 |
| Opc.Ua.Subscriptions.Classic.Tests | 57 | 0 |
| Opc.Ua.Bindings.Https.WebApi.Tests | 385 | 0 |
| Opc.Ua.Sessions.Tests | 782 | 379 |
| Opc.Ua.Subscriptions.Tests | 640 | 6 |
| Opc.Ua.Client.ComplexTypes.Tests | 2858 | 0 |

After merging current master (net10.0), every suite had 0 failures
except one, a flaky new test fixed in 9f52952b2:

| Suite | Passed | Skipped | Failed |
|---|---|---|---|
| Opc.Ua.Client.Tests | 2719 | 0 | 1 (the flaky test) |
| Opc.Ua.Redundancy.Client.Tests | 134 | 0 | 0 |
| Opc.Ua.Client.ComplexTypes.Tests | 2858 | 0 | 0 |
| Opc.Ua.Subscriptions.Classic.Tests | 57 | 0 | 0 |
| Opc.Ua.Bindings.Https.WebApi.Tests | 397 | 0 | 0 |
| Opc.Ua.Sessions.Tests | 790 | 379 | 0 |
| Opc.Ua.Subscriptions.Tests | 640 | 6 | 0 |

The touched test projects also build on net48 with 0 warnings.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: marcschier <11168470+marcschier@users.noreply.github.com>
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
2026-09-29 09:34:03 +00:00
Marc Schier 46fa7d364a Harden recovery, concurrency, and resource lifetimes across the OPC UA stack (#4516)
# Description

Bound managed-session recovery, preserve Publish workers and recovery
ownership, and address the client, server, transport, and certificate
audit findings and subsequent concurrency review. Also reduce the memory
retained by exhaustive session-test diagnostics.

## Recovery and Publish ownership

- Add `ManagedSessionOptions.ChannelReconnectTimeout` through direct
construction, the fluent builder, and DI. The automatic duration is
`max(3 * KeepAliveInterval, revised SessionTimeout, OperationTimeout)`,
sampled at cycle start. Positive overrides are supported;
`Timeout.InfiniteTimeSpan` explicitly opts out. Raw sessions retain
their unlimited default.
- Add `CreateReconnectBudget(TimeProvider)` as a required
`IReconnectParticipant` member, as agreed in review. Custom participants
implement it and may return null for no participant-specific bound.
- Enforce the earliest participant/caller deadline through transport
reconnect, activation/recreation, and subscription restoration. Late
callers can shorten an active cycle but cannot extend it.
- Cancel and unwind recovery, fence late responses, and release channel
recovery ownership before the existing `Faulted` event hands control to
the outer reconnect/failover policy. Preserve session recreate admission
through final Publish cleanup and keepalive suppression until shared
recovery is complete.
- Treat participant budget creation/evaluation failures, including
exceptions at the exact deadline, as terminal shared-recovery failures.
Notify participants before exposing `Faulted`, preserve the original
diagnostic, and never silently replace a finite budget with unlimited
recovery.
- Keep caller-supplied replacement channels, managed bindings, wrapper
event subscriptions, and recovery-owner identities consistent across
success, failure, and cancellation. Reject replacement during active
recovery and fence retired callbacks so they cannot clear newer
ownership or suppress later keepalive recovery.
- Retain eligible Publish workers through temporary
subscription-identifier clearing without retaining workers for
never-created or removed subscriptions. Preserve cancellation,
acknowledgement rollback, and drain-before-replacement ordering.
- Coordinate automatic subscription updates with session recovery:
cancel admitted updates, keep them paused across a failed-restoration
handoff, and retry only after explicit restoration completes. This
prevents competing CreateSubscription requests and updates against a
retiring session, while preserving manual recreation, transfer fallback,
and pending option changes.
- Exercise the real ManagedSession, V2 subscription engine, and channel
ready gate with scripted transports and an injected clock. Cover
transfer fallback, deadline handoff, late completions, and resumed
notification delivery.

## Audit and review corrections

- Correct certificate/trust-list transactions, change-pump lifetimes,
validation, peer revalidation, and reset/resource ownership.
- Harden node admission, attribute/range/dimension validation,
monitored-item sampling and lifecycle transitions, event fanout, and
server shutdown. Run lifecycle readiness and compensation outside shared
monitored-item admission, with stale-completion ownership checks.
- Close synchronous node-manager admission before teardown and retain
resources until admitted service, lifecycle, and asynchronous method
work returns. Dispose the monitored-item manager outside both locks,
reject late calls before they can reach it, and forward asynchronous
disposal through the adapter so the master awaits the same completion.
Preserve reentrant shutdown initiation, cancellation/failure unwinding,
and shared cleanup-failure reporting.
- Bound WSS pending-request retention using connection-local wire
handles while preserving caller-visible request handles and translating
Cancel targets. Safely ignore retired replies and drain admitted
send/close users before resource disposal.
- Clarify that the shared `ClientBase` caller-handle sequence is
distinct from the non-wrapping WSS wire allocator. Existing
exhaustion/reopen, late-reply, and Cancel-translation regressions verify
the connection-local contract; no allocator behavior was changed by this
clarification.
- Preserve virtual-node validation and resolver service errors instead
of converting them to cached misses. A mismatched NodeId reports
`BadNodeIdInvalid`; callback type mismatches and resolver service errors
keep their exact status. Per-item boundaries preserve unaffected reads,
writes, history operations, method calls, browse paths, and
monitored-item creation/restoration, including permission-validation
paths. Caller cancellation still propagates; stored-item validation
failures are logged without aborting later restores.
- Correct client file/role/state-machine/streaming APIs, node-cache
behavior, redundancy/failover ownership, and session
configuration/identity handling.
- Cancel each owned peer-discovery scope before disposing it, including
when the bounded wait wins a cancellation-delivery race. Keep late
results out of the endpoint cache and preserve single-flight lookup
ownership.
- Keep materialized alias Browse results synchronized with the live
store by default, preserving explicit startup-only opt-out. Apply
HistoryUpdate service results per value while retaining explicit
all-or-nothing provider APIs.
- Update the directly related feature documentation and add focused
positive, negative, concurrency, and ownership regressions.

## Latest review-feedback corrections

- Fence stale failed lease observations with a successful-confirmation
generation distinct from the revocation epoch. Snapshot it before each
store read, including failed-CAS revalidation, so an old failure cannot
revoke or reschedule a newer lease while fresh ownership loss still
revokes leadership. Preserve independent overlapping acquisitions,
expiry, disposal, and late-success protections.
- Isolate attributable WSS response-decoding errors to their request,
including retired handles. Keep admitted socket sends connection-owned
so caller timeout/cancellation cannot abort sibling requests; shutdown
still cancels and drains those sends.
- Restart keepalive and classic Publish replenishment after successful
session reuse. Retire V2 worker demand after intentional
deletion/disable without confusing that state with temporary recovery
resets.
- Browse virtual directories lazily across continuation pages without
the 1,024-entry snapshot cap. Preserve active-page cancellation, bounded
metadata retention, pushback, and exactly-once asynchronous cursor
cleanup.
- Apply certificate/CRL staging in last-operation order, preflight
required issuer storage before writes, select actual policy-compatible
RSA keys for None endpoints, frame certificate chains independently of
signature OIDs, and preserve admitted validation results during
rejected-writer shutdown.
- Preserve base asynchronous disposal when a legacy override omits its
base call; avoid double derived disposal in the adapter. Let genuinely
admitted nested work finish while rejecting stale captured contexts and
returning null from closed lookup APIs.
- Re-park recovered monitored items if AddNodes rolls back. Give event
compensation a fresh finite deadline, and preserve healthy
Browse/Translate siblings at every reference/path boundary while
retaining starting-node errors and caller cancellation.
- Give final reconnect notifications a live, bounded shutdown-linked
lifetime. Synchronize child state before parent lifecycle handlers
outside the parent transition lock.
- Document the accepted existing policies: direct reverse connections
are single-use without a ReverseConnectManager, and multi-node stream
capacity is shared rather than reserved per node.

The expanded readiness controls also exposed a real generation-handoff
race: an old source could finish draining after activation was deferred
but before readiness tasks were collected, causing the wanted
replacement to be omitted from the wait set. A deterministic test gates
that exact interval; the fix keeps the replacement in the readiness
wait. The original race passed 200 repetitions after the fix. A separate
control now awaits both producer readiness and iterator entry under the
same original deadline, rather than treating those independent signals
as equivalent. Temporary logging and repetition are removed.

## CI integration contracts

The History and Server CI failures exposed integration tests that still
asserted the behavior intentionally changed by the audit fixes. A
Windows WoT negative test raced its caller deadline against upstream
retries. A subsequent Ubuntu Client failure exposed a real
automatic-update versus explicit-restoration race:

- History insertion collisions now verify exact per-value statuses and
all persisted timestamps/values, including preservation of the existing
conflicting entry. Explicit atomic-provider rollback controls remain.
- Alias materialization tests wait for actual publication and verify the
added node plus forward/inverse `AliasFor` references, instead of racing
a startup-only snapshot expectation. Explicit refresh opt-out controls
remain.
- The unavailable-upstream WoT test uses an explicit finite retry policy
through existing DI configuration, preserving its original four-minute
guard and requiring a mapped-value service error before caller
cancellation. Production retry defaults remain unchanged.
- The Client fix retains the exact one-create and late-response
assertions. Three deterministic real-subscription/real-manager cases
cover paused creation, disposal while paused, and cancellation of an
admitted create followed by explicit restoration and a pending option
update. Both composed restoration-deadline cases also prove automatic
updates stay blocked at the outer handoff and resume after restoration.
- The merged-head net48 correction prevents lost peer-resolver
cancellation and distinguishes the harness's delayed initial `Connected`
event from actual outer recovery completion. A deterministic timer-order
test covers both cooperative and cancellation-ignoring resolvers,
cancellation before return, rejection of late cached results, and a
fresh subsequent lookup.
- The remaining CodeQL alert was a false content flow through
`ArrayOf.Count` into an integer-only trust-list summary. Projecting the
same count through `Span.Length` keeps cardinality distinct from
serialized contents without allocating, dropping diagnostics,
suppressing the rule, or dismissing the alert. Five log-contract cases
cover null/empty/nonempty results and mixed chain-capable/fallback
listeners, asserting the exact count, message, and structured
properties.
- Classic transfer acknowledges messages selected for asynchronous
Republish only after their responses arrive. The existing locked
replay-selection decision returns the immediate-acknowledgement subset
to Session, preserving the public transfer API, advertised availability,
and immediate acknowledgement of older gapped messages not selected for
replay. A callback changing `RepublishAfterTransfer` cannot change the
already-selected acknowledgement ownership.
- Transfer integration tests explicitly control acknowledged versus
retained origin messages. Exact assertions distinguish retained replay
from requested fresh initial values by sequence number, client handles,
values, status, and source timestamp. Atomic counters, observed
delivery/keepalive progress, and failure-safe session/file cleanup
replace timing assumptions and racy resets.
- Server lifecycle tests verify the documented independent five-second
compensation deadline rather than requiring a non-cancellable token.
They cancel the actual request, prove compensation and unrelated
monitored-item creation still proceed one tick before the deadline,
preserve the original failure and ownership assertions, and verify the
completed deadline is retired.
- Synchronous and asynchronous directory-browser tests require the exact
provider exception instead of an empty-directory success, then verify
the failed cursor is not enumerated again. These correct expectations
left behind by the intentional, documented provider-error propagation
change; production behavior is unchanged.

No tests were disabled, assertions loosened, coverage thresholds
lowered, or CI checks made optional. Existing platform exclusions and
Explicit debug variants remain.

## Related Issues

- Fixes #4514
- Fixes #4515
- Builds on merged #4503 and retains the #4508 publishing-drain
behavior.

## Validation

**Lease-election review correction
(`a13afa641182c70983e16bbcfebf507e666a45a5`):**

The correction is based on the existing upstream merge
`43079e2b851fe338a4082066f8d14abfdafb6e32`. Three deterministic
stale-verdict
cases fail on the original source and pass with separate confirmation
fencing.
Six new cases cover the initial foreign-owner verdict, failed-CAS
revalidation
in both invocation orders, and fresh ownership loss through both read
paths,
including revalidation begun after another successful confirmation.

| Target and configuration | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net10.0 Debug | 120 | 0 | 0 |
| net48 Debug | 120 | 0 | 0 |

The selection is the full `Opc.Ua.Core.Tests.Redundancy` namespace,
including
all 38 `SharedStoreLeaseElectionTests` cases and the existing expiry,
clock
rollback, disposal, and overlapping-success regressions. New witnesses
are
`StaleForeignLeaseReadDoesNotRevokeNewerAcquisitionAsync`,
`StaleFailedRevalidationDoesNotRevokeNewerAcquisitionAsync`, and
`FreshForeignLeaseObservationRevokesLeadershipAsync`. They assert
resulting
leadership, exact transitions, independent progress, and the unchanged
expiry
boundary. Retaining the initial generation for the fallback read
independently
makes the fresh-loss-after-confirmation control fail; that mutation was
removed
before the final rebuilt runs.

The successful scoped command is
`dotnet test tests\Opc.Ua.Core.Tests\Opc.Ua.Core.Tests.csproj -c Debug
--no-restore --filter
"FullyQualifiedName~Opc.Ua.Core.Tests.Redundancy"`,
with `CustomTestTarget` and `-f` matching each row and that framework's
assets
restored. Both changed C# files pass formatting and analyzers through
informational severity on both frameworks. These are scoped results, not
a
full-solution test or measured coverage-delta claim. CI monitoring is
paused
for this feedback-only operation; no current-head CI success is claimed.

**Latest CI contract correction
(`1cd1f2047bb5b50c9bf300b1ff710b0b2e935a29`):**

All four failing Server shard 23 jobs in
[run
36120946740](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/36120946740)
reported the same six cases. Two local replays reproduced all six
failures.
The source changes and documentation from `cd43b831a` establish both
intentional
contracts: independent bounded event compensation and surfaced provider
errors.
Only the two test files are corrected; production code and CI policy are
unchanged.

| Target and configuration | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net48 Debug | 113 | 0 | 0 |
| net10.0 Release, CI Coverlet settings | 113 | 0 | 0 |

The selection contains `MonitoredItemManagerLifecycleTests`,
`DirectoryObjectStateTests`, `DirectoryBrowserBoundedEnumerationTests`,
and

`EventCompensationReadinessHasFiniteDeadlineWithInfiniteSourceTimeoutAsync`.
Both changed files pass formatting and analyzers through informational
severity
on both frameworks. Independent mutations restoring a non-cancellable
compensation token and swallowing provider errors fail all four
lifecycle
cases and both browser cases, respectively. Both mutations were removed
before
the final passing runs and commit.

The scoped command is `dotnet test
tests\Opc.Ua.Server.Tests\Opc.Ua.Server.Tests.csproj`
with `CustomTestTarget` and `-f` set to the selected framework,
`--no-restore`, and
`--filter
"FullyQualifiedName~MonitoredItemManagerLifecycleTests|FullyQualifiedName~DirectoryObjectStateTests|FullyQualifiedName~DirectoryBrowserBoundedEnumerationTests|FullyQualifiedName~EventCompensationReadinessHasFiniteDeadlineWithInfiniteSourceTimeoutAsync"`.
The modern run additionally uses `-c Release /p:CollectCoverage=true
--collect "XPlat Code Coverage" --settings
tests\coverlet.runsettings.xml`.
These are scoped results, not a full-solution test or measured
coverage-delta claim.
Hosted checks for that commit were pending at publication. The fail-fast
CI
watch was stopped when the requested operation switched to review
feedback;
no current-head CI success is claimed.

**Earlier master merge (`8b15ea6ef9fc2214ac8ec886f373bb3846dd6d6f`, base
`b4136d8e9bab0df680f41d9ef985f519160534b1`):**

The `TcpListenerChannel` conflict preserves both lifetime
responsibilities:
disposal clears the retained peer-certificate chain and unregisters the
quota-scoped message-assembly scheduler. Both fields and all upstream
deadline
handling remain intact. The only additional manual source adjustment
adds the
parentheses required by the existing analyzer around the session-count
fallback.

Master advanced during validation. The initial transport merge
`80303c434ce813cf75aa7fe54a6a32fe2aeafc30` was retained, and the newer
base was
merged normally in `8b15ea6ef9fc2214ac8ec886f373bb3846dd6d6f`, without
rewriting
history. The additional recovery, fluent-pipeline, and test-framework
overlaps
were inspected; the branch's cancellation, validation-error, and
acknowledgement
ownership fixes remain alongside the upstream changes.

Full `UA.slnx` builds passed on net10.0 and net48 with **0 warnings and
0 errors**.
The final scoped tests rebuilt against the committed tree
`2074f8efcb61d8d9c6106e7d6f76ee941940e358`:

| Target | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net10.0 | 2,653 | 0 | 0 |
| net48 | 2,529 | 0 | 7 |

The net48 skips are existing platform exclusions: six RSA_DH_AesGcm
nonce cases
and one ClientWebSocket certificate-validation case requiring .NET 7 or
later.
The selection covers transport cleanup, reassembly
budgets/deadlines/admission,
peer-chain ownership, server session binding, fluent lifecycles and
source
generation, reconnect and keepalive, transfer acknowledgements, Publish
queues,
and JSON encoding. Modern-.NET WSS transport and real-server integration
cases
also pass. The resolved file passed solution-relative formatting and
analyzer
verification through informational severity on both frameworks.

These are scoped test results, not unfiltered full-suite or
measured-coverage
claims. Hosted CI was not monitored or repaired as part of this
merge-only
operation.

Selected local results below are overlapping validation runs, not
distinct-test totals.

**Earlier review-feedback batch
(`cd43b831a8f11de3f7d65c3681712a61e3c669a5`):**
The final net10.0 scoped selection passed **471 tests, with no failures
or skips**.
The final net48 solution-root selection passed **439 tests, with no
failures and
one unchanged platform skip**
(`ValidateServerCertificateFallsBackToTlsPolicyErrors`,
which requires newer ClientWebSocket certificate-validation support).
Both full nonincremental solution builds completed with **0 warnings and
0 errors**,
and all **40 changed C# files** passed informational-level
formatting/analyzer
verification. Both frameworks validated the identical final tracked
diff.
The focused matrix covers every one of the 20 current review threads,
including
real mid-frame WSS cancellation, stale admission contexts, directory
continuation
ownership, multi-element Browse/Translate failures, and the readiness
drain race.
The net10.0 solution-root test command has a separate pre-existing
runner conflict:
three unrelated AOT projects reject the VSTest target under
Microsoft.Testing.Platform
2.4.0 and SDK 10. Per-project net10.0 results are recorded separately;
no runner
migration, test exclusion, assertion relaxation, or CI-policy change is
included.
These are bounded selections, not unfiltered full-suite or measured
coverage claims.
At publication of `cd43b831a`, hosted CI was not green: the
`OPCFoundation.UA-.NETStandard` check reported `ACTION_REQUIRED`,
AppVeyor reported
`FAILURE`, and the two signed-build jobs were in progress. No CI jobs
were rerun,
cancelled, approved, or repaired as part of that feedback-only
operation.

**Classic transfer correction
(`f425376fca045794122e19aaf9cafebc4a717d91`):**
The preceding head's
[macOS net10.0 shard
25/30](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/35980326299/job/107570512458)
failed
`TransferSubscriptionTest(DisconnectedRepublish).TransferSubscriptionAsync(True,False)`
at the static-node count assertion: expected 10, received 20. The trace
contains a successful,
explicitly requested republish of retained sequence 1 and a fresh
initial-value batch at sequence 3,
not duplicate dispatch of one response.

Controlled lost origin acknowledgements reproduced that incorrect test
expectation on both the
preceding PR head and exact master base
`a2539cb53dd1666cef856f33812d7a8830d68909`.
The maintainer explicitly authorized correcting this existing issue in
the PR. Retained replay
and requested initial values are independent, as specified by
[OPC UA Part 4,
TransferSubscriptions](https://reference.opcfoundation.org/specs/OPC-10000-4/5.14.7).
The reason that the original hosted run retained its particular origin
message remains unproved.

The expanded full-suite run then exposed a **real production race**, not
just a count assertion:
Session queued acknowledgements for all transferred available messages
before the asynchronous
Republish responses arrived. Publish could delete those messages first,
causing
`BadMessageNotAvailable`. A gated real-Session/classic-engine regression
failed both replay-enabled
cases on the original implementation while both no-replay controls
passed. The ownership fix
passes all 24 combinations of empty/consecutive/unsorted-gapped queues,
replay preference,
sequential delivery, and a reentrant preference change.

All 40 normal real-server transfer cases pass on both frameworks.
Independent mutations
suppressing actual replay and duplicating observed sequence records each
fail the intended
assertion; both mutations were removed. The full classic suite passes on
both frameworks.
Hosted CI was pending when that correction was published; the earlier
failed hosted job was not
rerun for a lucky pass.

**Local net48 caveat:** the full Client run timed out in the
pre-existing fake-clock test
`ReconnectAsyncSwapsFaultedLeaseEntryAsync`, which does not exercise
subscription transfer.
Its unchanged isolated replay passed, but that does not resolve the
full-suite timeout.
No unrelated code or assertions were changed, and a clean full Client
net48 run is not claimed.

| Scope | net10.0 | net48 |
| --- | --- | --- |
| Full Client.Tests after transfer acknowledgement correction | 2,549
passed | 2,552 passed, 1 timeout failure noted above, 1 existing
platform skip |
| Full classic-subscription project after transfer correction | 57
passed, including all 40 normal transfer cases | 57 passed, including
all 40 normal transfer cases |
| Gated transferred-message acknowledgement ownership | 24 passed,
included above | 24 passed, included above |
| Saved-session consumer of the shared subscription helper | 40 passed |
16 passed, 24 existing unsupported-security-policy skips |
| Audit regression matrix | 2,339 passed | 1,934 passed, 34 existing
skips |
| Full Client.Tests after review follow-ups | 2,520 passed | Focused
selections only |
| Full Client.Tests after CI recovery correction | 2,523 passed, CI
coverage collector | 2,527 passed, 1 existing platform skip |
| Latest merged-head recovery/redundancy selection | 139 passed | 139
passed |
| Full Client.Tests after merged-head net48 correction | Focused
selection above | 2,529 passed, 1 existing platform skip |
| Lifecycle and actual-dimension regressions | 146 passed | 146 passed |
| Focused recovery follow-ups | 7 passed | 7 passed |
| WSS-related fixtures | 93 passed | Not applicable |
| CI History integration corrections | 28 passed | 28 passed |
| CI alias, dispatcher, and explicit-atomic controls | 63 passed | 63
passed |
| Full WoT sample project with CI coverage collector | 29 passed | Not
applicable |
| Trust-list effects and count-only summary contract | 22 passed | 22
passed |
| Virtual-node feedback, node-manager, dispatcher, and lifecycle
selections | 661 passed, 63 existing not-executed cases; all 48
virtual-node cases passed | 661 passed, 63 existing not-executed cases;
all 48 virtual-node cases passed |
| WSS wire-handle exhaustion, late replies, and Cancel translation | 9
passed | Not applicable |
| Synchronous node-manager disposal and related service/lifecycle suites
| 1,037 passed, 64 not-executed cases from existing fixture assumptions;
all 93 sampling/disposal cases passed | 1,037 passed, 64 not-executed
cases from existing fixture assumptions; all 93 sampling/disposal cases
passed |

- Full solution builds passed on net10.0 and net48 during the audit
work. The subsequent full non-incremental net10.0 build also completed
with zero warnings/errors.
- Modified source/test formatting and analyzer checks passed through
informational severity.
- Original composed recovery regressions passed repeated runs on both
frameworks. Independent mutations removing Publish cancellation,
bypassing the recreate drain call, or ignoring ready-gate cancellation
each failed the intended assertion; all mutations were restored before
passing runs.
- The latest recovery correction passed 100 executions of each original
restoration-deadline scenario with unchanged assertions. Restoring
premature update admission independently made both strengthened handoff
cases fail; the correct retention behavior was restored afterward.
- Startup-event and cancellation-delivery timing probes reproduced the
subsequent net48 failures, then passed 100 executions of each of the
three scenarios with the fixes. All timing probes and repetition were
removed. The permanent timeout-order regression also went RED on the
original cancellation cleanup without sleeps or scheduling
amplification.
- Final post-format recovery/subscription/engine checks passed all 151
selected cases on net10.0. The first local full net48 attempt aborted in
`clr.dll` with native access violation `0xc0000005`; an
unchanged-assembly full diagnostic rerun passed as recorded above. That
native host crash has not been attributed or claimed fixed.
- A minimal replay with the same CodeQL CLI and query-pack versions
reproduced the custom-count alert and confirmed that the standard
span-length projection is clean while direct sensitive-value and
raw-identifier logging controls remain flagged. The source was already
logging only a count; no identifier or certificate disclosure was
established at the reported location.
- The virtual-node feedback regressions first reproduced five
error-preservation/cache failures; expanded service-dispatch cases
exposed two additional whole-batch failures before the
operation-boundary fixes. The final selections pass on both frameworks.
Genuine misses remain cached, successful results remain reusable, failed
validation allows same-cache retry, and request cancellation still stops
the batch.
- Three deterministic synchronous-manager disposal regressions
reproduced early resource release and lifecycle calls reaching a manager
during disposal. The fix passes direct and adapted calls, a
sampling-worker join after the last operation exits, reentrant shutdown,
cancellation and failure paths, repeated disposal, and exact rejection
across 39 service/lifecycle entry points both during drain and after
cleanup. The original outside-node-lock disposal regression remains and
now requires the worker to observe closed admission.
- Prior-head CI on `c985f8bded77a60449d9cd381c8a004d8590ccf6` completed
with **168 passing checks, one expected release-package-publication
skip, and no failures or pending checks**. All test shards, signed
builds, container builds, the coverage check, and the CodeQL PR check
passed. Hosted CodeQL analysis `1829262912` completed successfully and
marks count-flow alert 385 fixed. This is evidence for that head, not a
claim that subsequent review follow-ups have completed hosted CI.

### Session-test diagnostic memory

Complete browse listings are streamed to unique NUnit attachments rather
than retained in inline NUnit/VSTest output. Detached regression-test
results are cleaned up without deleting runner-collected attachments.

- Two covered session-suite runs each completed with 782 passed and 379
existing skips. Peak working set fell from 4.86 GiB to 2.44-2.78 GiB.
- TRX output shrank from 303.1 MiB to approximately 40.7 MiB, retaining
all 46 complete browse attachments.
- Seven output regressions cover exact content, empty/single/large
listings, disabled/enabled output, bounded inline summaries, and unique
filenames.

The separate Azure build-18452 VM deprovisioning cause remains unproved
without provider logs. The memory measurements do not establish its
cause.

Unfiltered local `UA.slnx` tests, including the long stress/soak suites,
have not been run on both frameworks. A local coverage delta was not
collected; builds and focused tests are not substitutes for those
claims.

## Checklist

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [ ] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] All checks on the latest review-follow-up head have completed
successfully; prior-head CI passed as recorded above.
- [x] I have addressed **all** PR feedback received.

Tests have been added and pass as recorded above; the hosted coverage
check passed on the prior head identified above. The combined
tests/coverage-increase checkbox remains open because no local coverage
delta was measured.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 68f26810-22b8-476f-abcd-0a8c82d6e208
2026-09-25 14:59:34 +00:00
romanett e0c56a7c00 Replay the fuzz crash corpus from the fuzz-corpus orphan branch (#4539)
# Description

Since the move to GitHub Actions, CI replays only the checked-in fuzz
corpus. The full crash corpus used to be the Azure DevOps secure file
`FuzzingArtifacts.zip`, which `.azurepipelines/test.yml` overlaid onto
`Opc.Ua.Encoders.Fuzz.Tests`. The nightly `private-corpus` job that was
meant to replace it depended on an Azure storage account, federated
credentials and a protected environment. None of these were ever
provisioned, so the job never ran.

**The corpus now lives on the orphan branch
[`fuzz-corpus`](https://github.com/OPCFoundation/UA-.NETStandard/tree/fuzz-corpus)**
(commit `843ba944a7b144a7ae6429151846d9e5ab28d29f`, already pushed):
- It contains 22,267 `crash-*`, 25 `slow-unit-*` and 1 `timeout-*` input
under `Opc.Ua.Encoders.Fuzz.Tests/Assets/`.
- The files are byte-identical to the secure file (SHA-256
`85198e46…fe1d61b`), recovered from the `drop` artifact of Azure build
18397.
- The branch shares no history with `master`, so clones of `master`
don't get 22k extra files in their checkout.

**Why the corpus is no longer treated as private:**
- The inputs date from April–June 2024.
- The `drop` artifacts could be downloaded anonymously.
- Every master build printed up to about 7k base64 reproducers into
anonymously readable Azure logs.
- Current `master` replays every input without a test failure.

New, unfixed crashes still go through
[SECURITY.md](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/SECURITY.md)
and are added to the branch only after the fix ships.

## Changes

- **`nightly.yml`:** `private-corpus` is replaced by `crash-corpus`. The
new job:
- checks out the commit pinned in `FUZZ_CORPUS_COMMIT` (no secrets,
environment or OIDC);
- verifies the SHA and copies each top-level folder over
`fuzzing/<folder>`;
- runs `Opc.Ua.Encoders.Fuzz.Tests` on the 12 non-macOS profiles through
the shared `run-dotnet-tests` action and uploads
`crash-corpus-results-*`.

The `run_private_corpus` input and the INCOMPLETE label are removed. The
job runs on every scheduled and manual run, and the nightly summary
fails if it was skipped.
- **`fuzzing/CrashCorpus.md` (new):** the Azure history, branch layout,
how CI replays the corpus, local replay, and how to add inputs and move
the pin. `Fuzzing.md` links to it.
- **`docs/DeveloperGuide.md`:** the private-corpus section and its
secrets table are replaced, and the migration to-do list is updated.
- **`nightly.yml` AOT job (fix for a failure found by the first nightly
run):** the Linux and macOS legs looked up the published binary by
`BaseName`/`Extension`. A NativeAOT executable has no extension on those
platforms, so PowerShell splits `Opc.Ua.Aot.Tests` into `Opc.Ua.Aot` +
`.Tests`, and every leg reported *No NativeAOT executable was produced*
even though publish succeeded ([run
36017168717](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/36017168717),
`aot-ubuntu-latest`). The lookup now matches the exact file name. A
failure now reports the publish errors, a missing publish directory, or
which files were produced instead.
- **`Opc.Ua.Redundancy.Samples.Tests` / `Opc.Ua.WotCon.Samples.Tests`
(fix for failures found by the first nightly run):** the test runner's
framework guard rejected both projects on the nightly net8.0, net9.0,
net472 and netstandard2.1 profiles. Redundancy built a net48 placeholder
for every target except net10.0, and WotCon was pinned to net10.0. Both
now build the requested target on net8.0/9.0/10.0 and use
`RestrictForLegacyTfm` to become explicit not-applicable shells on
net48, net472, netstandard2.0 and netstandard2.1. The redundancy tests
no longer hard-code `bin/<cfg>/net10.0` when locating the sample
binaries, and `SampleAppProcess` falls back to an `object` lock below
net9.0. The net48 placeholder remains for Azure's plain `dotnet test -f
net48` leg. Checked locally by building Redundancy for
`CustomTestTarget=net9.0` and WotCon for `netstandard2.1`.
- **`DefaultServerRedundancyHandler` (fix for a failure found by the
first nightly run):** `ResolveServerAsync` gave the resolver a token
linked to the caller's, but waited on the caller's token directly. On
cancellation the wait could finish, and its `using` could dispose the
linked source, before the linked source's own callback had run. That
unhooks it, so the in-flight peer lookup never saw the cancellation
(`PeerDiscoveryPropagatesCallerCancellationAsync`, netstandard2.0 build
on net48). The wait now uses the linked token. A timeout is still logged
as a discovery failure, as before. A companion test fix makes
`PeerTimeoutPreservesOtherEndpointsAndCoalescesPendingDiscoveryAsync(False)`
deterministic. The timed-out lookup drains on the thread pool, so the
test's retry could join it and then have its own time limit expire
before it started a fresh lookup. The test now waits for the second
resolver call before advancing the fake clock.
- **`Session` keep-alive logging (found while investigating the net48
nightly failures):** `OnKeepAliveError` and the keep-alive read failure
log used `Endpoint?.EndpointUrl`. `ClientBase.Endpoint` dereferences the
transport channel, so once the channel was detached it threw a
`NullReferenceException` on every keep-alive tick, and
`BadNoCommunication` never reached the `KeepAlive` subscribers. Both now
log the configured endpoint's URL. Three new `SessionKeepAliveTests`
cover a detached channel.
- **`ClientTestFramework` shared session (fix for 67
`Opc.Ua.Sessions.Tests` failures on the net48 nightly):** the
fixture-wide shared session used the 10 s default session timeout. A
test-host stall of about 11–18 s while other fixtures restarted their
servers let the server expire it, and every later test in the
`ClientTest("https")` and `ClientTest("opc.https")` fixtures failed with
`BadSessionIdInvalid`. The shared session now requests
`SharedSessionTimeout` = 120 s; per-test sessions keep 10 s.
- **`run-dotnet-tests.ps1`:** `-QuietOutput` help text only; it no
longer names the removed job.

The Azure secure file stays in place, because `master378` and the 1.x
release pipelines keep their own `test.yml` and still use it.

## Verification

- `nightly.yml` parses as valid YAML, and no job, output or summary
field still refers to the removed job.
- I ran the job's overlay script against a clone of `fuzz-corpus` at the
pinned commit. It overlaid all 22,293 files, left the tracked
`Assets/Repo` untouched, removed the checkout folder and wrote the
summary line.
- **Not yet run:** the workflow itself. It is
`schedule`/`workflow_dispatch` only, so it needs a manual `nightly.yml`
run on this branch. On master the corpus has so far only been replayed
on Windows (net48/net10.0 in Azure), so the Linux legs are new ground.

## Follow-ups (admin)

- Add a ruleset for `fuzz-corpus`: require pull requests and block force
pushes and deletion, so the pinned commit stays reachable.
- The `fuzz-private-corpus` environment, if it was ever created, can be
deleted.

## Related Issues

- No issue exists yet; this is part of the Azure DevOps → GitHub Actions
migration (#4513, #4524).

## Checklist

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [ ] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [ ] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-25 07:49:00 +02:00
Marc Schier 57c0a32ed4 Fix incomplete-message buffering and channel cleanup (#4522)
# Description

Fix incomplete-message buffering, channel cleanup, session resource
accounting, and enforcement of existing transport admission settings.

- Share a targeted `ChunkReassemblyBudget` across server listeners. The
reference default is 64 MiB, with a 32 MiB global occupancy threshold
for sessionless intermediate chunks. This is priority headroom for
activated sessions, not a guaranteed bootstrap partition. Single/final
chunks and unrelated response/client buffers remain outside this budget.
- Retain precise incoming/final payload quotas, valid Abort handling
without channel teardown, terminal late-final rejection, and
exactly-once buffer/reservation cleanup.
- Use one assembly timer per quota/clock scope, asynchronous cleanup, a
fixed deadline, a 30-second fallback for non-positive lifetimes, and
best-effort ERR `BadTimeout` before closure.
- Apply negotiated TCP/WebSocket/Pipe receive limits and size pipe
rentals to actual chunks.
- Add the optional `ISessionBindingProvider` and immutable
`SessionBindingContext` seam. Managed membership counts distinct
committed sessions, not responses, and handles reactivation, transfer,
closure, expiry, restoration and shutdown. Read-only snapshots require
token/channel/security validation and never replace service
authorization.
- Wire default and explicitly injected binding providers through raw
TCP, Kestrel and UACP WebSockets; preserve existing callback/manager
interfaces and direct construction.
- Enforce existing `ConnectionRateLimiter` and channel capacity settings
on Kestrel TCP and UACP WebSocket admission, with physical-transport
leases surviving reverse handoff and releasing on cancellation, close,
failed attachment and stop. HTTP/JSON requests are not treated as UASC
channels.
- Add regression coverage and documentation. Stabilize the CI
cancellation test by waiting for the resolver to enter before canceling.

This is the foundation only. New Balanced/FairShare/TrustedReservations
policies, tenant isolation and guaranteed bootstrap reserves belong in
the separate stacked follow-up, not this PR.

## Related Issues

Fixes #4521.

## Validation

| Scope | Result |
| --- | --- |
| Core transport, budget, binding-context and DI tests, net10.0 | 717
passed |
| Core transport, budget, binding-context and DI tests, net48 | 664
passed, 6 platform-specific skips |
| Session bindings, transfer/security/expiry/restore and hosted DI,
net10.0 | 69 passed |
| Same focused Server suite, net48 | 69 passed |
| ServerRedundancyHandlerTests, Release/net48 | 39 passed |
| ConsoleReferenceServer net10.0 | Build succeeded, zero warnings/errors
|
| Server and HTTPS binding netstandard2.1 | Both builds succeeded, zero
warnings/errors |

The new admission fixtures also passed five repeated runs after
correcting asynchronous connection-context disposal. Full-solution
validation, coverage comparison and CI for this update remain pending.

## Checklist

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [ ] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.
2026-09-24 20:12:55 +02:00
Marc Schier 138086863b Fix audit findings and review regressions across the OPC UA stack (#4503)
## Scope

Audit fixes and review follow-ups across the OPC UA Core, Client,
Server, transport, and redundancy components. This includes implemented
Tier 1, Tier 2, and Tier 3 work; it does not claim that every item in
the 244-finding audit backlog is complete.

The review batch fixes mandatory full-key record protection and owned
plaintext buffers; transactional pending-certificate claims;
shared-channel nonce and certificate ownership; discovery and
token-policy validation; reconnect/callback ordering without changing
unbounded buffering defaults; server permissions, filters,
monitored-item lifetime, and alarm topology; historian paging,
retention, and annotations; atomic user/password metadata; and canonical
file identities with bounded alias and role refresh workers.

## Review-batch verification at `ab686ccae`

The following results come from fresh test builds using `dotnet test`,
`--no-restore`, `-m:1`, and an explicit `CustomTestTarget`. They replace
the earlier description's library-build/`--no-build` totals, which did
not establish the state of the merged test sources.

| Scope | Target | Passed | Skipped |
|---|---|---:|---:|
| Core review regressions | net10.0 | 827 | 0 |
| Client and lifecycle regressions | net10.0 | 630 | 0 |
| Server review regressions | net10.0 | 1970 | 0 |
| Redundancy Server / Client / PubSub | net10.0 | 276 / 10 / 11 | 0 |
| Sessions / file-and-alias / streaming / HTTPS-WSS integration |
net10.0 | 8 / 21 / 30 / 20 | 0 |
| Core review regressions | net48 | 786 | 39 |
| Client recovery and policy regressions | net48 | 54 | 0 |
| Server ownership, aliases, queues, and user-state regressions | net48
| 137 | 0 |

Every listed run exited successfully. The 39 net48 skips are existing
platform/capability cases. New key-agreement tests assert
unavailable-policy behavior on unsupported targets rather than adding
skips or pretending those targets performed an unsupported handshake.
Additional exact node/permission/filter/alarm checks passed 13 Core and
46 Server cases.

The PR-scoped formatter verification covers 26 projects and 389
non-generated C# files. A Roslyn syntax audit covers 53 changed
interfaces and 263 members, with no missing
parameter/type-parameter/return contracts and a 120-column limit for
their declarations and documentation. No full-solution,
all-target-framework, or NativeAOT matrix is claimed from these local
runs; the new CI run must establish its own result.

## CI follow-up at `e1bc3ac3b`

The follow-up fixes the failures reported by Azure build 18400. TLS
certificates retain configured DNS names, including mixed-case URI
schemes, without relaxing hostname validation. Reverse-WSS fixtures use
the DNS identity in the client certificate. Reconnect completion is
published only after cycle cleanup, so a subsequent reconnect cannot
join an old completed cycle and retain old certificates.

Certificate-alarm roots now support event subscriptions. The pump sample
has one continuous notifier path, with no duplicate shortcut. Historian
and aggregate fixtures share the provider's retention clock. Alarm
collection lets the server expire idle Publish requests rather than
canceling only the client wait. The corrected server, WoT, and
managed-session fixtures exercise valid requests and initialized
lifecycle contracts. Downlevel crypto tests preserve real credential and
key-ownership assertions without enabling unsupported raw-ECDH policies
or adding skips.

Fresh local evidence after integration includes:

| Scope | Target | Passed | Skipped |
|---|---|---:|---:|
| Client lifecycle / channel ownership / builder fixtures | net10.0 and
net48, each | 96 / 103 / 123 | 0 |
| Combined server lifecycle, events, aggregates, crypto, and contracts |
net48 | 358 | 0 |
| Full lifecycle plus certificate-alarm and aggregate fixtures | net10.0
| 116 | 0 |
| Final server-contract and history-routing delta | net10.0 and net48,
each | 84 | 0 |
| Subscription / XRegistry / WoT event regressions | net10.0 | 7 / 2 / 3
| 0 |
| Full Sessions project | net10.0 | 780 | 379 |
| Full ComplexTypes project / downlevel resolver fixtures | net10.0 /
net48 | 2854 / 15 | 0 |
| Full WoT project / downlevel structured-write fixtures | net10.0 /
net48 | 1496 / 27 | 0 |
| TLS domain-name regressions | net10.0 and net48, each | 21 | 0 |

All listed runs exited 0. The Sessions skips come from existing endpoint
and policy capability guards; they are not counted as passes. No skip
was added. Worker validation also covered full DI (426 passes), full
History (540 passes, 21 existing skips), 38 exact downlevel
event/history failures, and 60 repeated certificate-rotation race cases.
The final crypto fixtures passed 73 cases on each target with the
unchanged leak detector; a temporary premature-disposal mutation made
all three borrower tests fail and was then removed.

All 29 C# files in this follow-up pass included-file formatting at info
severity across 12 projects. The complete PR interface audit now covers
54 interfaces and 271 members with zero missing contracts or line-width
findings. No full-solution or NativeAOT matrix is claimed. New-head CI
has started and remains authoritative for the remote result.

## Test-result gate follow-up at `4b6e1203a`

Azure build 18401 reported the net48 Client job as successful despite a
test-host crash after only 264 passing tests. Its old evaluator counted
per-test failures but ignored the failed run verdict. This was a partial
run, not a benign exit after the suite had completed.

The shared result evaluator now rejects aborted, errored, incomplete,
malformed, or inconsistent TRX reports. Each file must describe a
completed run, so a passing file cannot mask another file's failure. It
retains support for completed runs followed by a benign nonzero host
exit, existing skipped-result conventions, and no-TRX MTP jobs.

All 78 regression cases pass after integration using Windows PowerShell
5.1. Real completed Sessions and Client reports also pass. The
process-test fixture follows the existing NET10_0-only tools-test
pattern; its net48 build is not counted as a test run. Formatting passes
for the added test file.

The Client host crash itself has not reproduced locally. The isolated
fixture passed 59 tests, and two fresh full fast-CI selections each
completed with 2,392 passes and three existing skips, including a run
with crash collection enabled. The CI merge tree is identical to the
tested source tree. No speculative runtime change was made, and the
original partial CI run is not claimed as a full-suite pass. Azure build
18402 has now completed the full net48 Client run: 2,392 passed, three
existing console skips, and a successful test-host exit. The corrected
evaluator independently validated outcome=Completed. Across the matrix,
119 test-project jobs succeeded; Sessions net10.0 was canceled when the
remote provider deprovisioned its runner, so the overall Azure pipeline
was canceled. That cancellation is not claimed as a code failure or a
successful run. CodeQL and three Docker image jobs were still running at
the latest check. The migration discovery failure remains separate.

## Documentation follow-up at `57ed02bea`

The environment blocker has been removed by the maintainer. The three
bundled migration references now exactly match the canonical documents
after deterministic link rewriting; all 15 bundled documents pass
`validate-migration-plugin.ps1`. The canonical migration prose was not
rewritten. `FileSystemClient.md` now documents that extended Windows
roots preserve literal trailing-dot names, completing the filesystem
review follow-up.

The filesystem thread has been replied to and resolved after
publication. The review pass now has 108 of 110 threads resolved. The
two explanation-only threads remain open as requested; no unfinished
change request is being represented as resolved.

## Cross-platform follow-up at `0d9d936a8`

With migration discovery restored, the Linux and macOS test matrix
exposed two stale durable-subscription expectations. The expected value
83,442 encoded the old 32-bit overflow when converting 3,600 hours to
milliseconds. The existing overflow-safe server correctly returns
14,400,000 lifetime intervals at a 900 ms publishing interval. Only
those two expected constants changed; production behavior,
negotiated-hour checks, and all other assertions remain unchanged.

The exact local lifetime selection reproduced both failures before the
correction. The full durable suite now passes 36 cases with 11 existing
skips on each of net10.0 and net48. All four lifetime cases executed and
passed on both targets, and included-file info-severity formatting
passes.

## Session shutdown follow-up at `8daf7f091`

A late net48 Sessions failure exposed a shutdown race. Canceling an
in-flight keepalive read can produce a transport
`ServiceResultException`. The retiring worker treated its own
cancellation as proof that the peer was unavailable, so `CloseAsync` or
`DisposeAsync` could skip the server-side `CloseSession` request. The
worker now ignores that service error only when its own token is
canceled; genuine peer errors still update liveness.

The full integration fixture reproduced the original error-code
mismatch. Four deterministic mock-transport cases then produced three
failures and one passing genuine-error control before the fix. They
verify successful close, returned server error, asynchronous disposal,
and unchanged behavior for a real keepalive failure. Fresh related runs
pass 75 client and 101 integration cases on each of net48 and net10.0,
with no skips. Ten repetitions of the formerly flaky full net48 fixture
pass all 1,010 cases. All three changed files pass info-severity
formatting, and temporary diagnostic instrumentation was removed.

## Atomic listener snapshot follow-up at `82dc22b5d`

Ubuntu Core CI exposed an unsafe formatter rewrite in TCP listener
disposal: `ConcurrentDictionary.ToArray()` had become a collection
spread. A concurrent channel removal between the spread's count and copy
operations could leave a default entry, causing a null dereference
during disposal. The listener now uses the dictionary's atomic `Values`
snapshot and disposes those channels outside the listener lock.

Deterministic regressions close zero, one, or all channels at the copy
boundary. Before the fix, the one/all-removal cases reproduced the exact
null dereference; the unchanged-count control passed. All 23
admission/listener cases now pass on net10.0 and net48, and the full
fast Core net10.0 suite passes 5,267 cases with 88 existing platform
skips. Both changed files pass info-severity formatting. A bounded audit
of the formatter's other snapshot rewrites found no further verified
unsafe concurrent-registry copies.

## Shutdown-test observation follow-up at `58403ee8b`

The net48 shutdown-order test raced its own observation: it read
`m_publishWorkerTask` after starting shutdown, which can legitimately
drain the worker and clear that field immediately. The test now captures
the worker before shutdown starts and confirms it is initially running.
It still requires the worker to finish while shutdown remains blocked by
the held manager semaphore. Production behavior is unchanged.

A temporary scheduling perturbation reproduced the exact null-field
failure. The corrected capture passed 100 perturbed iterations; both the
temporary repeat and yield were then removed. The final 126
subscription/lifecycle cases pass on each of net48 and net10.0, and
formatting passes. A complete local Sessions net10.0 run also passed 780
cases with 379 existing capability skips in 7m20s after the earlier
keepalive correction.

## Retirement and alias-startup follow-up at `1a048ff39`

The shadow-generation test now observes its documented asynchronous
cleanup through the existing bounded helper. Removing the replacement
does not join a background drain that already claimed the retired
generation. The test still checks live-registration removal immediately
and requires the old node to disappear; no timeout or production
lifecycle behavior changed. All 81 lifecycle cases pass on each of
net10.0 and net48.

Initial alias-node materialization now retries one timed-out, read-only
snapshot query before creating nodes for that root. The retry is logged
through source-generated logging. Each query retains the original shared
100 ms deadline; repeated timeouts, other errors, and cancellation still
abort startup. Client searches and live refresh do not gain this
immediate retry. Fault-injection tests cover success after one timeout,
a persistent timeout, a different store failure, and cancellation. All
187 related alias/hosting cases and the original certificate-rotation
integration case pass on each target; the positive test records exactly
one retry warning. The alias documentation now accurately describes the
shared request budget.

All changed C# files pass formatter checks, and the complete
54-interface/271-member documentation audit passes. Fresh CI is running
on `1a048ff39`; the previous completed matrix exposed only the two
failures corrected in this batch and their dependent summaries.

## Sample endpoint allocation follow-up at `d08a94925`

The strong-cluster test harness allocated OPC UA and Raft endpoints in
separate released-port batches. Uniqueness was enforced only inside each
batch, so the same OS-assigned port could appear in both protocol
groups. The harness now requests one distinct batch for both groups and
splits it before launching any replicas.

Deterministic one- and three-replica allocation cases reproduced
overlapping groups with the old plan and pass with the corrected plan.
The complete 17-case short-haul sample suite passes without skips; all
failover, historian-continuation, and service assertions remain
unchanged. Both changed files pass info-severity formatting. This
prevents intra-cluster self-collisions but does not claim to reserve
released ports against unrelated external processes.

## Code-review follow-up at `085fd9636`

A review of the complete branch diff found five defects this PR
introduced. All are now fixed, each in its own commit.

`RelatedTo`'s recursive-to-iterative rewrite defaulted the optional
`includeTypeDefinitionSubtypes` and `includeReferenceTypeSubtypes`
operands to `false`. Part 4 §7.7.4 specifies both default to `true`, so
a filter that omitted them silently stopped matching subtypes.
Dynamically created key-credential nodes derived their namespace from
the containing folder, which is the standard `i=18155` node in namespace
0 — the namespace reserved for the OPC UA standard address space; they
now resolve the server-owned namespace and fail with `BadInternalError`
rather than guessing index 1. The retained audience-less
`CreateTokenData` overload produced tokens that verification always
rejects, so it is now `[Obsolete]` and throws instead. A failed
reference to a remote parent left the new node registered with a
one-sided inverse reference, and is now rolled back. An existing `.pfx`
is restricted before it is rewritten, rather than after its new key
bytes are on disk.

One further reported finding was rejected after investigation.
`JwksIssuerKeyResolver` deliberately does not dispose retired key
snapshots: `RetiredKeysAreCollectibleWhileResolverRemainsAliveAsync`
proves the resolver retains no retired snapshot, and
`ReturnedKeysSurviveRepeatedRefreshAndResolverDisposalAsync` requires
already-returned keys to keep verifying across refreshes and resolver
disposal. Adding disposal would have broken that tested contract, so the
exploratory change was reverted.

Validated on net10.0 and net48: 256 Core and 633 Server cases pass, with
one pre-existing net48 skip. The build reports zero compiler and
analyzer diagnostics, all eight included-file info-format checks pass,
the contract audit covers 58 interfaces and 310 members with no
findings, and the 15 bundled migration documents validate. All 122
review threads are resolved; the key-credential namespace thread was
reopened to retract an earlier incorrect answer and then resolved
against the real fix.
## Review-body follow-up at `da0d59cfb`

The re-review at `8daf7f091 + 82dc22b5d` listed four items in its
summary that had no inline thread of their own, so they had not been
picked up. All four are now fixed.

Both event-dispatch permission gates had been tightened from not-Bad to
`IsGood`, which silently dropped events whose permission verdict is
Uncertain; the data-change path in the same file still treated Uncertain
as deliverable, so the two had diverged. `EventSourceRegistry` only
cleared `ConsecutiveFailures` when a source was deactivated, so a source
that had backed off to the 30-second cap kept that delay for the rest of
the process even after starting successfully.
`UserNameIdentityTokenHandler` built a temporary issuer chain whose
`Add` calls take independent certificate references, and never released
them.

The fourth was the receiver-side sequence rollover, which the reviewer
had correctly re-flagged as still open despite its thread being
resolved. `m_sequenceRollover` was set permanently, so the second legal
wrap on a long-lived channel was rejected and faulted the channel along
with the transport-reconnect OPN. OPC 10000-6 does not cap a
SecureChannel at one wrap. The flag is now cleared once an accepted
number has traversed the normal range, which keeps rejecting a replayed
low number that never left the rollover window.

Validated on net10.0 and net48: 636 / 593 Core cases and 135 / 134
Server cases pass, including the new
`UaSCBinaryChannelSequenceRolloverTests` and the Uncertain-permission
delivery cases. The build reports zero compiler and analyzer diagnostics
and the changed files pass included-file info-format checks on both
targets.

The previous head `085fd9636` was fully green: 279 checks passed and
Azure build 18414 succeeded with 137 of 137 jobs, after the platform
automatically retried a job whose NuGet tool download had hit a
transient TLS error.
## Reported issues #4508 and #4509 at `6ad1ecf16`

**#4508 (V2 subscription recreate deadlocks against a faulted transport)
was not yet fixed and is now closed by `bac260a06`.** Both drain sites
the report identifies were still unbounded. A publish worker that
started its request before the quiesce parks inside the service call on
the channel ready gate while holding an active publish request; the
recreate that would make the channel ready is the very operation
awaiting the drain, so the wait never ends.

The drain now cancels in-flight attempts through a per-attempt token
linked to the worker token. An aborted worker rolls its acknowledgements
back, releases the request and returns to the paused park instead of
terminating, so it resumes when the caller leaves the quiesce. Publish
ingress stays quiesced for the caller's operation, so
`DropPendingForSubscription` keeps the guarantee the report asks to
preserve and no blind timeout is added. The new regression parks a
worker on a cancellable gate that never completes on its own: it
reproduces the hang for the full 30-second budget before the change and
passes after it.

**#4509 (identity provider fails the initial connect) was already fixed
for its primary symptom.** `HandleConnectAsync` materializes the
provider's identity through `CreateIdentitySelectionContext` before the
first `CreateAsync`, so Anonymous is no longer substituted against a
UserName-only endpoint. `6ad1ecf16` adds the two remaining details from
the report: the enabled-policy set now includes the negotiated channel
policy, so a client cannot reject the policy it already accepted as
`NotEnabledByClient`; and when discovery has not populated the
endpoint's token policies the connect keeps the configured identity so
the attempt fails at the transport layer for the reconnect policy to
retry, instead of failing at the identity layer.

Validated on net10.0 and net48: 477 / 473 client session and
subscription cases pass, the build is free of compiler and analyzer
diagnostics, and the changed files pass included-file info-format checks
on both targets. The full `Opc.Ua.Sessions.Tests` suite also passes
locally on net10.0 with 782 passed and 379 pre-existing capability
skips.

GitHub checks are green on this head: Build and Test .NET 10.0, Docker
Sample Images CI, and NuGet Publish all succeeded. Azure build 18417
completed 134 of its 135 jobs successfully; its net10.0 Sessions job was
cancelled by the hosted-agent provider ("Received request to
deprovision"), the same infrastructure flake that hit build 18409
earlier on a head predating these changes. That job is not claimed as
passing, and the local full-suite run above covers the same project. The
previous head `da0d59cfb` completed Azure build 18415 with every job
succeeded.
## Review follow-up at `a08f0c12b`

Eleven new review threads arrived, nearly all documentation. Before
acting on each "this is new in 2.0" remark I checked the API against
`master378` rather than assuming, because a genuine 1.5 API still needs
its migration entry.

`ManagedSession`'s server-redundancy refresh had two hard-coded
two-second bounds. The new `ServerRedundancyOptions` exposes
`RefreshTimeout` for the metadata read and `PeerDiscoveryTimeout` for
each peer lookup, defaults both to the previous two seconds, validates
that a bound is positive or `Timeout.InfiniteTimeSpan`, and flows
through `ManagedSessionOptions`, `ManagedSession.CreateAsync`, the
fluent builder, and `DefaultServerRedundancyHandler`.

`AsyncCustomNodeManager` and `KeyCredentialBridgeAuthenticator` are both
absent from `master378`, so their obsolete members had no compatibility
constraint and are removed rather than carried:
`AsyncCustomNodeManager.ReadInitialValue`, the audience-less
`CreateTokenData` that only threw, and the audience-less `CreateProof`
that produced a proof no server accepts.
`CustomNodeManager2.ReadInitialValue` and the `MonitoredNode2` migration
section are genuine 1.5 APIs and are untouched.

The documentation now states master's behaviour instead of the delta
from 1.5.378, with each moved item already covered under
`docs/migrate/2.0.x/`. `IHistorianAnnotationProvider` is described by
its annotation-time key rather than as "legacy" — it is new in 2.0, so
the label implied a compatibility constraint that does not exist. The
KeyCredential bridge payload's `"version"` field is explained as a
vendor-extension format version with no OPC UA counterpart, and its
version-1 upgrade narrative is gone. `CertificateManager.md`'s migration
walkthrough is replaced by the resolver API it targets.
`NodeManagers.md`, `Sessions.md`, `AsyncServerSupport.md`,
`Certificates.md`, and `Profiles.md` no longer announce features
relative to 1.5. `Benchmarks.md`, `WhatsNewIn2.0.md`,
`DeveloperGuide.md`, and `docs/migrate/` keep their 1.5.378 references,
which are their subject.

CI then exposed a defect this batch introduced: five fixtures resolve
`ManagedSession`'s private constructor by its exact positional parameter
types, so the added parameter compiled cleanly but made `GetConstructor`
return `null` at run time. `7df1d5c40` updates every site;
`Redundancy.Client` passes 126 of 126 and the affected client fixtures
112 of 112.

The BouncyCastle question is answered and tracked in #4510:
`Opc.Ua.Core` already project-references `Opc.Ua.Security.Certificates`,
which already carries the conditional BouncyCastle reference, so the
raw-ECDH polyfill belongs there rather than as a new Core dependency.
The `IUserDatabase` metadata question is addressed to another maintainer
and is deliberately left open.

## Reported issue #4509 follow-up at `5d4d13d63`

The reporter verified `6ad1ecf16` and found one case still failing,
correctly. The empty-token-policies branch kept the configured identity
so a server that is down surfaces a transport failure rather than an
identity error. A provider-only configuration has no configured
identity, so it kept `null`: `OpenCoreAsync` turned that into Anonymous
and `OpenValidateIdentity` rejected it with `BadIdentityTokenInvalid`,
silently ignoring the configured provider.

The branch now requires a configured identity to defer to. Without one
the provider is consulted, so its own `BadIdentityTokenRejected` names
the offered and rejected policy set instead. Two regression tests cover
both configurations; the first fails against the previous behaviour by
reaching the session factory with a `null` identity, which is the exact
step that produced the reported error. That branch had shipped without a
test, which is why the case was missed.

## Review and CI status at `5d4d13d63`

**All actionable review threads are resolved: 132 of 133.** The single
open thread is a question the reviewer addressed to another maintainer
about moving user metadata into `IUserDatabase`; it is left open for
them rather than resolved silently. Every resolved thread carries a
reply naming its fix commit.

**Latest-head CI is green on `5d4d13d63`: 279 checks passed, zero
failed, zero pending**, with one conditional signed-package publishing
job skipped. Local validation for this batch: the full
`Opc.Ua.Client.Tests` suite passes 2,430 of 2,430 on net10.0,
`Opc.Ua.Redundancy.Client.Tests` 126 of 126, and `Opc.Ua.Server.Tests`
590 of 590 for the affected selections. Both net10.0 and net48 build
clean for `Opc.Ua.Client`, `Opc.Ua.Server`, and the changed test
projects, and all changed files pass included-file info-severity
formatting on both targets.

The PR remains open; no merge was performed. As stated at the top, this
does not claim that every item in the 244-finding audit backlog is
complete.
## Latest CI follow-up at `b6f2dfa43`

Azure build 18442 exposed a net48 compile regression in the Kafka
adapter: `RuntimeHelpers.GetUninitializedObject` is unavailable on .NET
Framework. Commit `2cf1e0eed` now uses normal `ProducerMessage`
construction on `NETFRAMEWORK` while retaining reflection-based
construction for modern targets that can load a different Dekaf runtime
asset. The exact net48 CI selection passes 92 of 92 tests, and the
netstandard2.1 adapter guard selection passes 11 of 11.

After merging the latest `master`, GitHub Actions run 35643592139 is
green. The initial Ubuntu Core.Schema job built successfully and passed
160 of 160 tests, then hit an external 403 while finalizing its
test-result artifact; its failed-job rerun completed successfully. Azure
build 18451 was canceled when its remote provider deprovisioned the
net10.0 Sessions runner (`Received request to deprovision: The request
was cancelled by the remote provider`). Azure attached no test task log
or source error, and the canceled parent left that child check stale as
in-progress. No source workaround, test skip, or check relaxation was
made for either infrastructure failure.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 68f26810-22b8-476f-abcd-0a8c82d6e208
2026-09-22 09:10:58 +02:00
Marc Schier 7411654c8d Complete OPC UA Part 11 Historical Access (#4390)
# Description

Completes the OPC UA Part 11 Historical Access work requested by #4387
and
the historian framework integration requested by #4400.

The conformance/evidence catalog covers all 37 released UACore 1.05
Historical Access profiles: 15 Server facets and 22 Client facets,
together
with the standard aggregate functions and their conformance units.
Server
facets are advertised only when the resolved providers expose their
required
interfaces and capabilities.

## Server and provider support

- Completes raw, modified, at-time, processed, annotation, structured,
and event history.
- Dispatches best-effort, bulk, and transactional updates with aligned
statuses, old values, diagnostics, and rollback state.
- Supports mixed history-update detail types and batched
structured/annotation operations.
- Uses composite identities and exclusive cursors for same-timestamp
structured, modified, and event values.
- Captures live data and events, installs historical configuration
objects, and emits typed audit payloads.
- Derives aggregate monitoring filters from per-node historian
capabilities and rejects unsupported processed aggregates before
provider dispatch.
- Supports tri-state `Historizing`: set, clear, or preserve
provider-owned state.

## Client support

- Exposes modified values together with `ModificationInfo`.
- Adds event-history reads and event insert/replace/update/delete
operations.
- Adds structured and annotation batching with strict response
validation.
- Shares continuation handling and release-on-abandon across read
families.
- Accepts inherited standard event fields rooted at event subtypes.

## Review hardening

- Registers DI-selected historians before node-manager reconciliation
and capability publication, while preserving provider ownership.
- Uses committed Raft read barriers for linearizable `TryGetAsync` and
`ScanAsync`.
- Keeps claimed continuation state immutable until a fresh successor is
saved, restoring the original after transient failures.
- Uses exact-incarnation compare-and-delete so delayed cleanup cannot
remove a restored same-ID continuation.
- Cleans up indeterminate initial and replacement saves, and propagates
shutdown cancellation through cleanup resolution.
- Preserves legacy continuation envelopes/cursors and distinct
annotation parent/property identities.
- Deletes every structured entry at a requested timestamp and uses the
complete modified-history ordering tuple.
- Shares native/fallback at-time and AnnotationCount calculations,
including reverse endpoints and cross-framework fractional intervals.
- Primes modified aggregate items before buffered live delivery and
deduplicates history/live overlap using provider-specific identities.
- Keeps committed Modify results successful while reporting priming
failures
  through the monitored item's notification queue.
- Keeps protected-notification state live-only for queues larger than
one.
Queue size one retains the newest notification without pinning errors or
transferring priority during resizing. Durable restore retains ordinary
definitions, last values/errors, and raw queues without recreating
priority.
- Isolates aggregate calculation, modification preparation, and
historical/live
handoff in `AggregationFilterHandler`, retaining existing
provider/factory
wiring and supported past-start behavior. The larger-queue protection
policy
  is unchanged pending the open review discussion.
- Uses one `IMonitoringFilter` owner for protocol filters or the
aggregation
handler, eliminating parallel effective-filter storage and retaining the
current definition during preparation. The original client filter stays
distinct.
- Integrates current master, retaining custom monitored-item creation
decisions and per-node history callbacks.

## Redundant-server alignment and samples

- Adds a protected shared historian with immutable segments, manifest
CAS publication, writer fencing, and restart recovery.
- Persists portable continuation state before exposing it to clients and
transfers ownership during mirrored-session takeover.
- Rejects eventual-consistency and active/active multi-writer historian
configurations rather than silently degrading.
- ReferenceServer and ConsoleReferenceClient demonstrate discovery,
paging, raw/modified/at-time/processed reads, annotation/structured
CRUD, event capture, and event CRUD.
- RedundantServer and RedundantClient demonstrate active/passive
history, continuation recovery after replica termination, and
post-promotion writes.
- Updates Historical Access, High Availability, profile, migration, and
sample documentation.

## Compatibility

- New 2.0 collection boundaries use `ArrayOf<T>` and public byte
payloads use `ByteString`.
- Removes the legacy public virtual
`SamplingGroupManager.CreateMonitoredItem` /
`ModifyMonitoredItem` entry points and protected creation factory, as
agreed
  in review. Migration guidance points to the monitored-item manager and
  construction-decision APIs.
- Retains established persisted formats and current write layouts.
Retired interim
notification-state formats (sample v2 / shared v4) are rejected, as
agreed in review.
- Keeps the historian integration compatible with .NET Framework and
NativeAOT.

## Validation

### Latest CI source repair

`73c619435` forwards the existing cancellation token at both
predefined-node
creation calls in the PR-added History event fixture. The merged
lifecycle
overload exposed these two CA2016 errors, which blocked History jobs,
the
solution build matrix, and CodeQL on GitHub and Azure. The exact
compiler
failure was reproduced locally; the repaired fixture passes 4/4
integration
cases on net10.0 and 4/4 on net48 with clean scoped diagnostics. No
assertions,
tests, coverage thresholds, or CI configuration were weakened.

The repaired History jobs on Linux/macOS and all four Azure solution
builds
now pass. The Windows all-TFM GitHub job instead lost its hosted
runner's
connection; no build log was recoverable, and GitHub recorded a
runner-loss
annotation rather than a compiler/test diagnostic. One unchanged retry
was
requested. Remaining checks are monitored with
`gh pr checks --watch --fail-fast --interval 30`; CI is not yet reported
as green.

### Latest base integration

`bd52e5fea` merges upstream `master` at `da7412c42`. The lifecycle
conflict
retains upstream's shared cancellation-aware registration helper and the
historian behavior. The hosted-historian fixture forwards its existing
token
to the new lifecycle overload. GDS project renames and all three AOT
test
hosts are retained, with their project references resolving after the
merge.

| Integrated scope | net10.0 | net48 |
| --- | --- | --- |
| Server lifecycle, fluent authoring/import, historian, monitored-item
and hosting regressions | 732 passed | 732 passed |
| NodeState lifecycle regressions | 216 passed | 216 passed |
| Automatically merged Raft client fixtures | 28 passed | 28 passed |

No selected tests failed or were skipped. The manually resolved files
pass
scoped formatting/analyzer checks. One CA1861 warning remains in the
incoming
`NodeSetImportIntegrationTests.cs`; that file is byte-identical to
upstream
master and was not rewritten or suppressed during integration.

### Latest feedback follow-up

`102954eaa` replaces split filter references with the shared
`IMonitoringFilter`
contract implemented by protocol filters and `AggregationFilterHandler`.
Targeted server regressions pass **103/103 on net10.0 and 103/103 on
net48**;
scoped formatting/analyzers are clean, and the updated XML-documentation
inventory has zero gaps across 188 non-generated PR C# files.

`93c5b5db8` renames `AggregationFilterHandler`, makes it the owner of
the
server-revised aggregate filter while preserving the original client
filter,
and removes the retired interim notification-state readers. Server
regressions
pass **101/101** and shared-store regressions **64/64**, on both net10.0
and
net48, with no failures or skips. Runtime-file formatting/analyzers are
clean.

`5ccf45630` completes the public/internal XML-documentation sweep. The
Roslyn
inventory finds zero undocumented eligible declarations across all 186
non-generated PR C# files; the 110-file documentation slice changes only
XML
comments and spacing. `f17765475` applies the three requested Markdown
edits.

### Earlier feedback follow-ups

`a53950737` removes single-slot notification pinning and extracts
aggregate
implementation from MonitoredItem. Targeted sampling, aggregate
modification,
history/live handoff, queue/lifecycle, restore, and serialization cases
pass
**101/101 on net10.0 and 101/101 on net48**, without failures or skips.
Scoped formatting/analyzers are clean; the focused review found no
significant
issues. The final formatted monitored-item fixtures also pass 45/45 on
net48.

The preceding `b21555568` removes the legacy sampling API bridge and
durable
notification-priority state. Its targeted Server cases passed 97/97 and
shared
subscription-store cases passed 64/64 on each framework. The broader
evidence
below remains pinned to its original tested commit, not attributed to
these
follow-ups.

### Earlier integrated-implementation validation

Validated implementation commit: **`3efae597f`**. The following commit,
`f6dbefb1c`, only adds two explanatory comment lines for the final
standards
review; it changes no executable code.

| Scope | net10.0 | net48 |
| --- | --- | --- |
| Server | 5,187 passed; 56 skipped | Affected surface: 2,160 passed; 1
reproduced baseline failure; 56 skipped |
| Client | 2,202 passed; 2 skipped | 2,204 passed; 5 skipped |
| History integration | 519 passed; 21 skipped | 519 passed; 21 skipped
|
| Redundancy server | 641 passed | 641 passed |
| Redundancy client | 124 passed | 124 passed |
| Core shared-store regression suite | 23 passed | 23 passed |

All six affected samples passed non-incremental Release/net10.0 builds
with
zero warnings and errors: ConsoleReferenceClient,
ConsoleReferenceServer,
RedundantServer, RedundantClient, MinimalBoilerServer, and
PumpDeviceIntegrationServer.

The published self-contained win-x64 NativeAOT executable is 116,924,928
bytes and has no CLR header or managed runtime dependency. Direct
execution
passed **HistoryAotTests 3/3** and **RaftAotTests 2/2**.

Final standards and specification reviews found no confirmed outstanding
high/medium functional gaps or hard standards violations. The remaining
constructor-purpose clarification is addressed in `f6dbefb1c`.

### Reproduced baseline exceptions

The net48 hosted-startup timeout also reproduces in a pristine worktree
at
the previous PR head, `24cf1416d`, in

`RegisterPostStartRegistriesWiresHistorianAndAliasStoresOnPlainServerAsync`,
with the same subsequent certificate-leak assertion. The corresponding
renamed case fails before startup in the reviewed branch as well. This
is
reported separately from the net48 affected-surface results, not counted
as
a passing full Server suite. The net48 matrix selected the historian,
aggregate, monitored-item, fluent, and continuation surfaces and
excluded
the Hosting namespace.

`DurableDataValueQueueVerifyReferenceBatchingAsync` failed at item 1000
in
the net48 affected-surface run and passed its single isolated rerun. The
same
failure at the same assertion reproduces on pristine `849e16acc`; the
test,
sample queue, queue factory, and batch persistor are unchanged. The
original
failure remains in the table rather than being erased by the rerun.

### CI source repairs

- `4be7eb8f7` keeps diagnostics/configuration managers out of
distributed
address-space replication. Those managers inherit the source interface,
but their live server state and redundancy metadata must remain
replica-local.
  The ownership regression passes on net10.0 and net48, and all nine
  redundancy sample CI tests pass locally.
- `d17f467b3` completes the sample startup repair: core managers are
also
replica-local; the startup banner no longer advertises readiness before
initialization; the producer starts after distributed services; and
native
Raft startup no longer forces disruptive extra elections. The full
sample
suite passed 9/9, with initialized `RedundancySupport=Hot`, and focused
  Raft/address-space regressions passed 8/8 and 3/3.
- `81b0b72be` moves the unchanged distributed-historian NativeAOT
scenario
into a smaller, always-run companion executable to bound Apple's linker
input. All 137 AOT tests remain present; the moved test and helpers are
  unchanged. GitHub and Azure publish/run both native executables, with
separate result directories where they share a job. The companion passed
actual Windows NativeAOT execution. Linux and Intel macOS CI passed both
  executables, but this split alone did not fix ARM64 macOS linking.
The remaining historian graph is rooted by ReferenceServer startup, not
just the relocated test. No test exclusion or speculative linker setting
  was added to conceal it.
- `8a5842913` isolates the independent MCP test graph into an always-run
native host. The existing MCP source and assembly leak hooks are linked
  unchanged, and evaluated compiler inputs prove exactly one owner for
  every test source: 133 main + 3 MCP + 1 historian = 137 declarations.
All three hosts run on every AOT platform. The main Windows native
object
is 9.35% smaller; both changed publishes had zero diagnostics. MCP
passed
  3/3; the identical main executable passed 133/133 on one unfiltered
followup after two initial endpoint-discovery connection failures, which
  remain recorded in the local evidence.
- The previous Intel macOS job successfully published and executed its
native
tests, then failed on artifact-upload DNS (`ENOTFOUND`). No upload gate,
  shared environment setting, or cache configuration was disabled.

The first repair round also encountered the unrelated
`MetricsAreEmittedForChannelLifetimeAsync` timing failure on macOS Core.
Neither that test nor channel-manager code is changed by this PR, and
its
assertions remain intact. It passed unchanged on the final repair head.

On `d17f467b3`, the Linux and macOS redundancy sample jobs pass; the
remaining
failure was ARM64 Apple's `too many large addends` assertion. The
verified
upstream relocation-anchor fix (dotnet/runtime#124721, backport
dotnet/runtime#132171) is not present in the shipping ILCompiler
10.0.11.
An experimental multi-module probe failed and was rejected, not added to
CI.
On `8a5842913`,

[`aot-macos-latest`](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/34102158680/job/101678934057)
successfully publishes and executes all three native hosts on ARM64:
136 main runtime cases, 1 historian case, and 3 MCP cases, with no
skips.
The previous Apple linker blocker is resolved. Linux NativeAOT also
passes.
No assertion, test, shared environment setting, cache, or required gate
was
weakened.

The same CI run reports a separate macOS Sessions teardown failure: all
662 executed tests pass, but the global leak assertion detects one
undisposed certificate. The MCP partition changes no runtime, Sessions,
or
test-fixture code. A single unchanged diagnostic rerun is queued once
GitHub
permits rerunning that job; the failure is not suppressed or counted as
green.
Other CI checks are still pending.

## Related issues

- Fixes #4387
- Fixes #4400

## Checklist

- [ ] I have signed the CLA and read the contributing guide.
- [x] I have added regression tests and directly related documentation.
- [x] I have retained working reference and redundant-server sample
wiring.
- [x] Final validation and review evidence is complete, including the
baseline exceptions above.
- [ ] All required CI checks pass; the fail-fast rerun for `73c619435`
is pending.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 9dbd9527-d818-47a0-984c-fbb1472d3d6b
2026-09-08 11:32:23 +02:00
Marc Schier 7cec2d614d Move repository files to the consolidated layout 2026-07-16 06:25:54 +02:00