fix: disconnect old session on Telegram /attach switch

[saucam]

Summary

• Root cause: #handleAttach never called disconnectClient before attaching to a new session. Since every Telegram user has a fixed clientId (telegram:<userId>), switching sessions left the old session's client registration intact — causing it to keep streaming into the same chat. With 7 sessions cycled through, multiple old sessions accumulated as registered clients simultaneously.
• #handleAttach: Calls disconnectClient, clears the streaming buffer, and deletes the dangling ⏹ Stop button before attaching to a different session (the Stop button normally gets deleted by the old session's idle status_change, which won't arrive after we disconnect).
• #handleDetach: Consistently clears streaming buffer and stop-button state (previously only nulled attachedSessionId/attachedSessionName).

Test plan

• src/tests/session-client-tracking.test.ts — 14 tests using real Session objects (no SDK); covers the regression shape (both sessions hold the client without detach), the fix (detach-then-attach routes only to new session), scrollback replay going to the correct send function, and the disconnectClient sweep across N sessions
• src/tests/telegram-session-switch.test.ts — 17 tests mirroring the UserState state machine offline (no Grammy); covers first-attach, same-session re-attach, cross-session switch, streaming buffer isolation, stop-button deletion, and cycling through 7 sessions
• Full suite: bun test src/tests src/daemon — 494 pass, 0 fail

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved Telegram session switching and detaching so chat state is cleaned up correctly.
  • Old session connections are now disconnected when switching sessions, and leftover streaming content is cleared.
  • The “⏹ Stop” control message is removed when no longer needed, preventing stale controls from staying in chat.

[coderabbitai]

📝 Walkthrough

Walkthrough

Extends Telegram attach and detach handlers to clean up streaming buffer content and delete any active stop-control message when switching or leaving sessions. Two new test files are added: one for Session client-tracking invariants and one for the Telegram-specific attach/detach/switch state logic using offline helpers.

Changes

Telegram session attach/detach cleanup

Layer / File(s)	Summary
Attach/detach cleanup in Telegram frontend src/frontends/telegram/index.ts	On /attach to a different session, disconnects the prior client, clears session ids, empties the streaming buffer, and deletes any active stop-control message. On /detach, also clears the streaming buffer and deletes the stop-control message in addition to existing disconnect logic.
Session client-tracking unit tests src/tests/session-client-tracking.test.ts	Tests Session.attach/detach count invariants, same-clientId replacement, scrollback replay delivery, and the detach-then-attach session-switch regression with cross-session sweep behavior.
Telegram session-switch and detach logic tests src/tests/telegram-session-switch.test.ts	Offline UserState types and performSwitch/performDetach helpers drive test cases for first-time attach, same-session reattach, stop-message deletion, multi-session cycling, and streaming buffer isolation across switches.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly reflects the main change: disconnecting the old Telegram session when /attach switches sessions.
Docstring Coverage	✅ Passed	Docstring coverage is 85.71% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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• Create stacked PR
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• Create PR with unit tests
• Commit unit tests in branch fix/telegram-session-switch-leak

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.34%. Comparing base (f5f46e9) to head (7471ee7).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #29       +/-   ##
===========================================
- Coverage   80.61%   58.34%   -22.27%     
===========================================
  Files          45       46        +1     
  Lines        4782     6943     +2161     
===========================================
+ Hits         3855     4051      +196     
- Misses        927     2892     +1965     

Flag	Coverage Δ
daemon	58.34% <ø> (-22.27%)	⬇️

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see 2 files with indirect coverage changes

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[coderabbitai]

🧹 Nitpick comments (1)

src/tests/telegram-session-switch.test.ts (1)

24-112: 📐 Maintainability & Code Quality | 🔵 Trivial | 🏗️ Heavy lift

Avoid testing a duplicated state machine copy.

performSwitch/performDetach mirror production behavior, so tests can still pass when real handler logic drifts. Extract the cleanup/switch logic into shared pure helpers and import them here to test the real contract.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/tests/telegram-session-switch.test.ts` around lines 24 - 112, The tests
are exercising a duplicated copy of the session switch/detach state machine
instead of the real contract, so drift in `#handleAttach` and `#handleDetach` can go
unnoticed. Extract the cleanup/switch behavior into shared pure helpers used by
TelegramFrontend, then update the test to import and verify those helpers
directly rather than maintaining local mirrors like performSwitch and
performDetach.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@src/tests/telegram-session-switch.test.ts`:
- Around line 24-112: The tests are exercising a duplicated copy of the session
switch/detach state machine instead of the real contract, so drift in
`#handleAttach` and `#handleDetach` can go unnoticed. Extract the cleanup/switch
behavior into shared pure helpers used by TelegramFrontend, then update the test
to import and verify those helpers directly rather than maintaining local
mirrors like performSwitch and performDetach.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: a5a8c6da-0788-4ef8-9344-a703e66bf236

📥 Commits

Reviewing files that changed from the base of the PR and between 721bc09 and 7471ee7.

📒 Files selected for processing (3)

• src/frontends/telegram/index.ts
• src/tests/session-client-tracking.test.ts
• src/tests/telegram-session-switch.test.ts