fix(console): preserve chat messages when updateSession is called

[leoleils]

Problem

When switching pages (e.g. to MCP or Model settings) during an LLM streaming response or tool call, chat messages in the current session are lost and cannot be recovered even after refreshing.

Root Cause

SessionApi.updateSession (in console/src/pages/Chat/sessionApi/index.ts) had session.messages = [] on its first line, which forcefully cleared the messages array on every call. When the UI called updateSession to sync session metadata during streaming, the empty messages array overwrote the existing messages in sessionList via the spread operator { ...this.sessionList[index], ...session }.

Fix

• Removed session.messages = []
• Used destructuring const { messages, ...metadataUpdate } = session to exclude the messages field from the merge, so updateSession only touches metadata (name, realId resolution, etc.)
• All other logic (realId resolution, fallback refresh, return value) remains unchanged

Tests

Added property-based tests (vitest + fast-check):

• Bug condition test: confirms messages are preserved after updateSession
• Preservation tests: verifies metadata update, realId resolution, fallback refresh, and return value behavior remain unchanged

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical bug in the chat session management where chat messages were inadvertently cleared when updateSession was invoked. The fix ensures that message data is preserved during session metadata updates, preventing data loss in the UI. Additionally, comprehensive property-based tests have been introduced to validate the fix and maintain the integrity of other session management functionalities.

Highlights

• Bug Fix: Chat Message Preservation: Resolved an issue where chat messages were lost when updateSession was called, particularly during LLM streaming or tool calls, due to an erroneous session.messages = [] assignment.
• Refactored Session Update Logic: Modified the updateSession method to use object destructuring (const { messages, ...metadataUpdate } = session) to ensure only session metadata is updated, leaving the messages array untouched.
• Introduced Property-Based Testing: Added comprehensive property-based tests using vitest and fast-check to validate the bug fix and confirm that other expected behaviors of updateSession (metadata updates, realId resolution, fallback refresh, return value) remain unchanged.

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Changelog

• console/package-lock.json
  • Added fast-check and vitest dependencies, along with their transitive dependencies.
  • Removed some nested fdir, picomatch, and tinyglobby entries from node_modules/@typescript-eslint/typescript-estree/node_modules and node_modules/vite/node_modules.
  • Removed pathe and tinyexec from node_modules/mermaid/node_modules.
  • Added new top-level fdir, pathe, picomatch, tinyexec, tinyrainbow, obug, siginfo, stackback, std-env, why-is-node-running, expect-type, magic-string, pure-rand, chai, assertion-error, and @vitest/* packages.
• console/package.json
  • Added fast-check and vitest as dev dependencies.
• console/src/pages/Chat/sessionApi/index.ts
  • Refactored updateSession to prevent clearing chat messages by destructuring the session object and only merging metadata.
  • Updated the tempId assignment to use the destructured metadataUpdate.id.
• console/src/pages/Chat/sessionApi/sessionApi.test.ts
  • Added new test file containing property-based tests for SessionApi.updateSession to verify message preservation and other functionalities.
• console/vitest.config.ts
  • Added new Vitest configuration file for running tests, including path aliases and test environment settings.

Activity

• The pull request introduces a fix for a known bug where chat messages were lost during session updates.
• New testing infrastructure (vitest, fast-check) has been set up to ensure the robustness of the fix and prevent regressions.
• The changes include both bug resolution and the addition of comprehensive tests, indicating a thorough approach to quality assurance.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a bug that caused chat messages to be lost when updating a session. The approach of using object destructuring to separate metadata from messages is clean and effective. The addition of property-based tests using vitest and fast-check is a great improvement, ensuring the fix is robust and preventing future regressions. I have one suggestion to enhance type safety in the implementation.