Address review feedback on idempotency docs and stores

[KSemenenko]

Summary

• block the Orleans idempotency grain from restarting commands that already completed while still resetting failed attempts before retrying
• ensure the memory cache idempotency store reclaims per-command semaphores with key-based removal and refresh the README guidance to avoid mid-word line breaks

Testing

• ~/.dotnet/dotnet test ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj (fails: ObjectDisposedException in ServiceCollectionExtensionsTests when resolving CommunicationLogger from a disposed service provider)

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https://chatgpt.com/codex/tasks/task_e_68e9fbc7ad5c83268e969223e18fcead

[Copilot]

Pull Request Overview

This PR improves the Orleans idempotency grain to properly handle command restarts and enhances the memory cache idempotency store's concurrency management while adding comprehensive documentation.

• Enhanced Orleans grain logic to block restarting already completed commands while allowing failed command retries
• Replaced global locking with per-command semaphores in the memory cache store for better concurrency
• Added detailed documentation covering command correlation/tracing identifiers and idempotency architecture

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
README.md	Added extensive documentation on command correlation/tracing identifiers and idempotency architecture
MemoryCacheCommandIdempotencyStore.cs	Replaced global semaphore with per-command locking system using reference counting
CommandIdempotencyExtensions.cs	Refactored execution flow and improved null result handling
CommandTests.cs	Added tests for timestamp validation and GUID version verification
CommandIdempotencyTests.cs	Added comprehensive concurrency and edge case tests
OrleansCommandIdempotencyStore.cs	Enhanced result retrieval logic with proper type checking
CommandIdempotencyGrain.cs	Improved command restart logic to block completed commands while allowing failed retries
CommandIdempotencyExtensions.cs (AspNetCore)	Applied same execution flow improvements as core extensions

[Copilot]

Race condition vulnerability: between TryRemove and TryAdd, another thread could add a different lock for the same commandId, causing the wrong lock to be restored. Consider using CompareExchange or a more atomic approach to handle concurrent modifications safely.

Suggested change

	if (_commandLocks.TryRemove(commandId, out var existingLock) && !ReferenceEquals(existingLock, commandLock))
	{
	_commandLocks.TryAdd(commandId, existingLock);
	}
	_commandLocks.TryRemove(commandId, commandLock);

[Copilot]

Complex negated pattern matching reduces readability. Consider using positive matching with an explicit list of allowed statuses or restructure the conditional logic for better clarity.

Suggested change

	else if (state.State.Status is not CommandExecutionStatus.NotFound and not CommandExecutionStatus.NotStarted)
	else if (!(state.State.Status is CommandExecutionStatus.NotFound || state.State.Status is CommandExecutionStatus.NotStarted))

[chatgpt-codex-connector]

💡 Codex Review

Communication/ManagedCode.Communication.Orleans/Stores/OrleansCommandIdempotencyStore.cs

Lines 87 to 99 in 3fe4476

	// New atomic operations
	public async Task<bool> TrySetCommandStatusAsync(string commandId, CommandExecutionStatus expectedStatus, CommandExecutionStatus newStatus, CancellationToken cancellationToken = default)
	{
	var grain = _grainFactory.GetGrain<ICommandIdempotencyGrain>(commandId);
	var currentStatus = await grain.GetStatusAsync();
	if (currentStatus == expectedStatus)
	{
	await SetCommandStatusAsync(commandId, newStatus, cancellationToken);
	return true;
	}
	return false;

TrySetCommandStatusAsync reports success without owning Orleans lock

The Orleans implementation of TrySetCommandStatusAsync checks the grain’s current status and returns true whenever it matches the expected value, but it does not verify that SetCommandStatusAsync actually transitioned the grain to InProgress. Two concurrent callers can both read NotFound before either call persists the new state; each then invokes SetCommandStatusAsync, where the first succeeds and the second is rejected by TryStartProcessingAsync. Because this method still returns true for the second caller, both ExecuteIdempotentAsync invocations proceed as if they have exclusive ownership and the command body runs twice. TrySetCommandStatusAsync must only return true when the underlying grain really acquired the processing state (e.g., by wiring the boolean result from TryStartProcessingAsync).

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[chatgpt-codex-connector]

💡 Codex Review

Communication/ManagedCode.Communication.Orleans/Stores/OrleansCommandIdempotencyStore.cs

Lines 87 to 99 in 3fe4476

	// New atomic operations
	public async Task<bool> TrySetCommandStatusAsync(string commandId, CommandExecutionStatus expectedStatus, CommandExecutionStatus newStatus, CancellationToken cancellationToken = default)
	{
	var grain = _grainFactory.GetGrain<ICommandIdempotencyGrain>(commandId);
	var currentStatus = await grain.GetStatusAsync();
	if (currentStatus == expectedStatus)
	{
	await SetCommandStatusAsync(commandId, newStatus, cancellationToken);
	return true;
	}
	return false;

TrySetCommandStatusAsync reports success without owning Orleans lock

The Orleans implementation of TrySetCommandStatusAsync checks the grain’s current status and returns true whenever it matches the expected value, but it does not verify that SetCommandStatusAsync actually transitioned the grain to InProgress. Two concurrent callers can both read NotFound before either call persists the new state; each then invokes SetCommandStatusAsync, where the first succeeds and the second is rejected by TryStartProcessingAsync. Because this method still returns true for the second caller, both ExecuteIdempotentAsync invocations proceed as if they have exclusive ownership and the command body runs twice. TrySetCommandStatusAsync must only return true when the underlying grain really acquired the processing state (e.g., by wiring the boolean result from TryStartProcessingAsync).

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting

• @codex fix this CI failure
• @codex address that feedback

[KSemenenko]

@codex fix all comments

[chatgpt-codex-connector]

Summary

• Ensured per-command semaphores are only removed when the stored lock instance matches, eliminating the race between TryRemove and TryAdd. ManagedCode.Communication/Commands/Stores/MemoryCacheCommandIdempotencyStore.csL106-L115
• Rewrote the Orleans grain’s start-logic to use a status switch that clearly distinguishes allowed restart cases from completed or concurrent executions. ManagedCode.Communication.Orleans/Grains/CommandIdempotencyGrain.csL30-L57
• Updated the Orleans store so TrySetCommandStatusAsync succeeds only when the grain actually acquires processing ownership. ManagedCode.Communication.Orleans/Stores/OrleansCommandIdempotencyStore.csL88-L104

Testing

• ⚠️ dotnet test ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj (fails: dotnet CLI is unavailable in the execution environment)

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