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romanett
36194f6a02
## Summary Allocation audit of the per-message / per-value paths (binary codec, built-in types, server request path, monitored items, client notification dispatch) looking for boxing and avoidable per-value copies. Measured with `GC.GetAllocatedBytesForCurrentThread` probe loops on net10.0 **and net48**, and with `dotnet-trace` allocation traces of the server load harness (#4707) for read/write/browse/subscription, server and client side — a value type in the "allocated types" list is a box. Wire output and error behaviour are unchanged. ### Fixed | Where | Cause | Frequency | Before → after | |---|---|---|---| | `Polyfills/System.IO.cs` (net48/netstandard2.0) | `BinaryWriter.Write(ReadOnlySpan<byte>)` polyfill copied with `ToArray()` — every string, array, ByteString, Guid write | per value | 32–64 B → 0; BrowseResponse×50 encode 15.3 → 10.9 KB | | `EnumHelper` (net48/netstandard2.0) | `EnumToInt32`/`Int32ToEnum`/`EnumToInt64` boxed outside `NET8_0_OR_GREATER` (every enum field, `Variant.From<TEnum>`, `EnumValue.From`) | per value | 24 B → 0 | | `BinaryDecoder.ReadString` + stream raw reads (net48) | temp `byte[]` per string, `BinaryReader.ReadBytes` | per value | BrowseResponse×50 decode 15.7 → 11.3 KB | | `WriteGuid` / `ReadGuid` (all) | `ToByteArray()` / `byte[16]` | per value (also Guid NodeIds) | 40 B → 0 each | | `VariantHelper.TryCastTo<TEnum>` (`DataValue.GetValue<TEnum>`), `EventRecordFieldReaders.GetEnum` | `Enum.ToObject` box | per call / per event field | 24 B → 0 | | `NodeManagerServiceDispatcher.GetManagerHandleAsync` | interface enumerator per validated node | per node | Write-100: 151.8 → 148.5 KB/request | ### Cold paths (third commit) - `Server.Auditing` write handler: `Convert.ToBoolean(object)` got a boxed `Variant` (not `IConvertible`) and threw `InvalidCastException` on any in-process write; now takes the boolean, `BadTypeMismatch` otherwise (new test). - `UpdateServerServiceLevel`: `Convert.ToByte(byte, IFormatProvider)` bound to the object overload. - Client publish-state / recovery-policy `HasFlag` (boxes on net48) → `(x & F) == F`. - `SequenceReader` big-endian float on net48/netstandard2.0 used `Convert.ToSingle(int)` (numeric conversion) instead of reinterpreting the bits. - JSON enum strings: one `Enum.GetName` + `string.Concat` instead of `IsDefined` + boxing `CoreUtils.Format`; same output (new test for the `EnumValue` overload). Left as is: `SamplingGroup` start-up `Convert.ToInt32(double, provider)` (rewritten by #4707), `SecureChannelRenewed` formatting (transport files in flight on the client perf branch), `Utils.IsEqual<T>` object path for structs (cold callers; changing it would mix `CompareTo` and `Equals` semantics), Machinery `HasFlag` (startup config). ### Not changed here - `BinaryEncoder.GetNodeIdEncoding` `Convert.ToUInt32(object)` / `Convert.ToByte(enum)` (72 B per NodeId encode, largest single item) and `ChannelAsyncOperation.Complete` boxing the `int` result are handled on the client performance branch. - By design: `Variant` / `NodeId` store `ArrayOf<T>`, Guid, ByteString identifiers boxed (`Variant.Copy` re-boxes RolePermissions during permission checks). ## Tests - New `BinaryCodecAllocationTests`: round trips in buffer and stream decoder mode, truncation errors, allocation per call (< 1 B/call over 20k calls; the counter can be off by an allocation quantum when other tests GC). - `Enum.ToObject` equivalence for `TryCastTo` and `EventRecordFieldReaders.GetEnum` across all underlying types. - net10.0 (third commit): Types 11465, affected Server 87, Client subscription 642 passed; net48 Types 11458 passed, `UA.slnx` 0 warnings. - net10.0: Types 11464, Core.Encoders 2947, Server 8386 passed; Core 6197 passed, 1 unrelated (`ActivityTraceFlags_Metrics_ShouldRecordMetricsOnly`, passes alone). - net48: Types 11457, Core.Encoders 2947, EventRecordFieldReaders 25 passed; `UA.slnx` builds with 0 warnings. 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>