Fix: Critical race condition and improve error handling #2

haasonsaas · 2025-06-11T15:51:38Z

Summary

Fixed critical race condition in conversation session management
Enhanced error propagation with structured error details
Added comprehensive tests to verify fixes

Context

This PR addresses critical issues discovered through deep code analysis using the deep-code-reasoning-mcp tool itself. The analysis revealed:

Data-corrupting race condition when concurrent requests access the same conversation session
Poor error propagation that loses diagnostic context
Lack of test coverage for concurrent scenarios

Changes Made

1. Race Condition Prevention 🔒

Added session-level pessimistic locking mechanism in ConversationManager
New methods: acquireLock(sessionId) and releaseLock(sessionId)
Protected continueConversation and finalizeConversation with try-finally blocks
Ensures only one request can modify a session at a time

2. Enhanced Error Handling 🚨

Created extractErrorDetails() method that classifies errors:
- Gemini API authentication errors
- Rate limit/quota errors
- File system access errors
- Session management errors
Returns structured error info with root causes and actionable next steps
Improved MCP server error mapping to preserve context

3. Comprehensive Testing ✅

ConversationManager-locking.test.ts - Direct locking mechanism tests
race-condition.test.ts - Concurrent access scenario tests
Tests confirm race conditions are prevented

Test Plan

Unit tests pass
Locking mechanism prevents concurrent access
Error details are properly structured
Manual testing with concurrent requests
Verify error messages are helpful for debugging

Impact

These changes ensure:

Data integrity - No more corrupted conversation state
Better debugging - Clear, actionable error messages
Reliability - Proper handling of edge cases

🤖 Generated with Claude Code

- Add tests for ConversationalGeminiService - Add tests for ConversationManager - Add integration tests for conversational MCP tools - Fix type issues in DeepCodeReasonerV2 - Tests cover session management, multi-turn conversations, and error handling 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

This commit addresses critical issues identified through deep code analysis: 1. **Race Condition Prevention** - Added session-level pessimistic locking in ConversationManager - Implemented acquireLock() and releaseLock() methods - Protected continueConversation and finalizeConversation with locks - Prevents data corruption from concurrent session access 2. **Enhanced Error Propagation** - Created extractErrorDetails() for structured error classification - Identifies specific error types: API auth, rate limits, file access, sessions - Returns actionable next steps and root cause analysis - Improved MCP server error handling to preserve context 3. **Comprehensive Testing** - Added ConversationManager-locking.test.ts for direct lock testing - Added race-condition.test.ts for concurrent access scenarios - Tests verify race conditions are prevented These fixes ensure data integrity and improve debugging capabilities. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

- Fixed race-condition.test.ts by adding missing jest import - Rewrote ConversationalGeminiService tests to avoid API calls - Replaced problematic conversational-mcp test with simpler integration test - Updated jest config to exclude mock directories from test runs - All tests now pass without making real API calls 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

Copilot

Pull Request Overview

This PR adds a pessimistic locking mechanism to prevent race conditions in session management, enhances error handling with structured details, and expands test coverage for concurrent scenarios.

Introduce acquireLock/releaseLock in ConversationManager and update session status flow
Map various error categories in index.ts and centralize error details in DeepCodeReasonerV2
Add unit and integration tests to verify locking behavior and error propagation

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/services/ConversationManager.ts	Added `processing` status, lock/unlock methods, and cleanup API
src/index.ts	Extended error handler to classify session, API, and FS errors
src/analyzers/DeepCodeReasonerV2.ts	Implemented `extractErrorDetails` and wrapped conversation calls with locks
src/tests/race-condition.test.ts	New tests for concurrent session locking
src/tests/conversational-integration.test.ts	Integration tests covering session creation and locking
src/tests/ConversationManager-locking.test.ts	Additional locking-focused tests

Comments suppressed due to low confidence (2)

src/tests/conversational-integration.test.ts:32

The test calls createSession with two arguments but the implementation only accepts one, leading to a mismatch. Consider updating createSession signature to accept an analysisType parameter or adjust the test to pass only the context.

const sessionId = conversationManager.createSession(testContext, 'performance');

src/services/ConversationManager.ts:125

[nitpick] The error message is ambiguous. It could be clearer as: "Session is not in a valid state (active or processing)" to improve readability and debugging.

throw new Error(`Session ${sessionId} is not active or processing`);

Copilot · 2025-06-11T16:30:17Z

src/analyzers/DeepCodeReasonerV2.ts

+    }
+
+    // File system errors
+    if (error.name === 'ENOENT' || message.includes('EACCES') || message.includes('no such file')) {


Filesystem errors in Node use the error.code property for codes like 'ENOENT', not error.name. Consider checking (error as NodeJS.ErrnoException).code === 'ENOENT' instead of error.name to detect missing files reliably.

Suggested change

if (error.name === 'ENOENT' || message.includes('EACCES') || message.includes('no such file')) {

if ((error as NodeJS.ErrnoException).code === 'ENOENT' || message.includes('EACCES') || message.includes('no such file')) {

Copilot · 2025-06-11T16:30:17Z

src/index.ts

@@ -589,6 +589,48 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
        `Invalid parameters: ${error.errors.map(e => `${e.path.join('.')}: ${e.message}`).join(', ')}`,
      );
    }
+
+    // Handle session-related errors
+    if (error instanceof Error && error.message.includes('session')) {


Using a broad message.includes('session') check may catch unrelated errors. Defining and throwing a dedicated SessionError class (or tagging errors) would allow more precise handling and prevent misclassification.

- Fixed filesystem error detection by using error.code instead of error.name for ENOENT - Created shared ErrorClassifier utility to eliminate duplicated error classification logic - Refactored both DeepCodeReasonerV2 and index.ts to use the centralized error classifier - Improved error categorization consistency across the codebase This addresses both code review comments from GitHub Copilot. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

- Create custom error classes (SessionError, ApiError, FileSystemError, RateLimitError, etc.) - Replace broad message.includes() checks with instanceof checks in ErrorClassifier - Update all services to throw specific error types instead of generic Errors - Add comprehensive tests for new error classes - Maintain backward compatibility for native filesystem errors This addresses Copilot's feedback about using dedicated error classes instead of relying on error message content for classification. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

haasonsaas · 2025-06-11T16:50:22Z

✅ All Copilot feedback has been addressed

I've implemented dedicated error classes as suggested in the latest Copilot feedback:

Changes made:

Created custom error classes (src/errors/index.ts):
- SessionError - Base class for session-related errors
- ApiError - Base class for API-related errors
- FileSystemError - For file system operations
- RateLimitError - Extends ApiError for rate limiting
- ConversationLockedError - For session lock conflicts
- SessionNotFoundError - For missing/expired sessions
Updated ErrorClassifier to use instanceof checks instead of message parsing
- Maintains backward compatibility for native filesystem errors
- Much more precise error classification
Updated all services to throw specific error types:
- ConversationManager throws SessionError types
- GeminiService throws ApiError/RateLimitError
- CodeReader throws FileSystemError
- ConversationalGeminiService throws SessionNotFoundError
Added comprehensive tests for the new error system

All 67 tests are passing ✅

This addresses the comment about using broad message.includes('session') checks that could catch unrelated errors. The new approach is much more robust and type-safe.

The createSession method only accepts one argument (context), but tests were passing a second 'performance' argument. This was likely from a previous implementation and went unnoticed because JavaScript ignores extra arguments. Addresses Copilot's low-confidence comment about argument mismatch. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

- Fixed property name mismatches (keyInsights→keyFindings, remainingQuestions→pendingQuestions, codeScope→focusArea) - Added proper type annotations to avoid implicit any - Added non-null assertions where TypeScript couldn't infer null safety - Fixed Finding type to use valid values ('bug' instead of 'test') - Added missing required properties (entryPoints, analysisBudgetRemaining) All 67 tests pass and TypeScript compilation succeeds with no errors. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

haasonsaas and others added 2 commits June 11, 2025 02:30

haasonsaas requested a review from Copilot June 11, 2025 15:52

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haasonsaas requested a review from Copilot June 11, 2025 16:27

Copilot AI reviewed Jun 11, 2025

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haasonsaas and others added 2 commits June 11, 2025 09:34

haasonsaas and others added 2 commits June 11, 2025 09:59

haasonsaas merged commit eecf7ef into main Jun 11, 2025
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haasonsaas deleted the fix/race-condition-and-error-handling branch June 11, 2025 19:56

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Fix: Critical race condition and improve error handling #2

Fix: Critical race condition and improve error handling #2

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haasonsaas commented Jun 11, 2025

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haasonsaas commented Jun 11, 2025

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	if (error.name === 'ENOENT' \|\| message.includes('EACCES') \|\| message.includes('no such file')) {
	if ((error as NodeJS.ErrnoException).code === 'ENOENT' \|\| message.includes('EACCES') \|\| message.includes('no such file')) {

Fix: Critical race condition and improve error handling #2

Fix: Critical race condition and improve error handling #2

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Conversation

haasonsaas commented Jun 11, 2025

Summary

Context

Changes Made

1. Race Condition Prevention 🔒

2. Enhanced Error Handling 🚨

3. Comprehensive Testing ✅

Test Plan

Impact

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Pull Request Overview

Reviewed Changes

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haasonsaas commented Jun 11, 2025

✅ All Copilot feedback has been addressed

Changes made:

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