fix(pi): capture isIdle before awaiting reportSession to avoid stale ctx throws

[ccharname]

Problem

The pi integration's session_start handler awaited reportSession() (up to ~2s of socket retries) before reading ctx.isIdle():

pi.on("session_start", async (event, ctx) => {
  ...
  await reportSession(event?.reason);
  agentActive = ctx?.isIdle?.() === false; // stale ctx if session replaced meanwhile
  publishState(true);
});

If the session is replaced/reloaded during that window (ctx.newSession() / ctx.fork() / ctx.switchSession() / ctx.reload()), pi invalidates the captured extension ctx and the post-await access throws This extension ctx is stale after session replacement or reload. Because the throw happens inside an async event handler, it surfaces as an unhandled promise rejection — which by default terminates the process on modern Node, killing the agent pane.

Fix

Read isIdle synchronously before the await; the value cannot change across the report since a replacement emits a fresh session_start on the new runtime anyway:

const wasActive = ctx?.isIdle?.() === false;
await reportSession(event?.reason);
agentActive = wasActive;

Verification

bun test src/integration/assets/herdr-agent-state.test.ts — 14/14 pass, including the reload-preserves-state and replacement-report tests.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 01ee9494-9196-4e58-bb89-cc0222ab0477

📥 Commits

Reviewing files that changed from the base of the PR and between 9a4ce5e and cc8fc70.

📒 Files selected for processing (1)

• src/integration/assets/pi/herdr-agent-state.ts

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📝 Walkthrough

Walkthrough

The session_start handler now captures the agent state before asynchronous reporting and reuses that state afterward. This avoids reading a potentially replaced session context after reportSession completes.

Changes

Session state capture

Layer / File(s)	Summary
Capture state before session reporting src/integration/assets/pi/herdr-agent-state.ts	session_start evaluates ctx.isIdle() before reportSession and assigns the captured active-state result after reporting.

Estimated code review effort: 2 (Simple) | ~5 minutes

Possibly related PRs

• herdrdev/herdr#2159: Modifies the same session_start session-state handling in herdr-agent-state.ts.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the fix for stale context errors by capturing isIdle before awaiting reportSession.
Description check	✅ Passed	The description explains the stale context problem, the synchronous state capture fix, and the test verification.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[greptile-apps]

Greptile Summary

The PR moves the pi integration's isIdle read before the asynchronous session report to avoid accessing an invalidated context.

• Captures the activity state synchronously during session_start.
• Applies and publishes the captured state after session reporting completes.
• Leaves an out-of-order completion path where a superseded handler can overwrite replacement-session state.

Confidence Score: 4/5

The PR should not merge until a superseded session_start handler is prevented from overwriting and publishing the replacement session's activity state.

Independent asynchronous session reports can complete out of order, and the older handler unconditionally commits its pre-await snapshot to shared state after it resumes.

Files Needing Attention: src/integration/assets/pi/herdr-agent-state.ts

Important Files Changed

Filename	Overview
src/integration/assets/pi/herdr-agent-state.ts	The synchronous context read avoids the stale-context exception, but the delayed unconditional assignment can publish superseded session state when reports complete out of order.

Sequence Diagram

sequenceDiagram
    participant O as Old session_start
    participant N as New session_start
    participant S as Shared agent state
    O->>O: Capture old isIdle
    O->>O: Await reportSession
    N->>N: Capture new isIdle
    N->>N: Await reportSession
    N->>S: Set and publish new state
    O->>S: Resume, overwrite and publish old state

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[greptile-apps]

Superseded handler overwrites current state

If replacement and original session_start handlers overlap, the original handler can resume after the replacement, assign its earlier wasActive snapshot to the shared agentActive, and force-publish an incorrect idle or working state.

[ogulcancelik]

i can't repro a case where session gets replaced between session_start and reportSession(). could you open an issue with exact repro case please?