fix(gateway): time-gate SSE reconnect history reload (#2404) by serrrfirat · Pull Request #2415 · nearai/ironclaw

serrrfirat · 2026-04-13T16:47:03Z

Summary

Fixes [QA] Page refreshes too often — tab switching triggers full chat refresh #2404 — tab switching triggers full chat refresh
Every SSE reconnection (browser tab switch, transient network error) unconditionally called loadHistory(), which clears the entire chat DOM and re-renders all messages — losing scroll position and causing visible flicker
Now tracks disconnect timestamp (_sseDisconnectedAt) and only reloads history if disconnected for >10 seconds
Brief reconnects preserve the existing DOM; the "Done without response" safety net (fix: web UI messages stuck until refresh — SSE event ordering bug #2079) handles the rare case of missed events during short disconnections

Changes

crates/ironclaw_gateway/static/app.js: Add _sseDisconnectedAt tracking, set it in visibilitychange and onerror handlers, replace unconditional loadHistory() in onopen with 10s time-gate
tests/e2e/scenarios/test_sse_reconnect.py: Set simulated long-disconnect timestamp before reconnect in the stale-event-ID test so it still exercises the history reload path

Test plan

E2E: pytest scenarios/test_sse_reconnect.py — all existing reconnect tests pass
Manual on staging: open chat, send a message, switch browser tabs, return — chat should not flash/reload
Manual on staging: disconnect for >10s (e.g., network toggle) — chat should reload to catch missed messages

🤖 Generated with Claude Code

…witch flicker (#2404) Every SSE reconnection unconditionally called loadHistory(), which clears the entire chat DOM and re-renders all messages — losing scroll position and causing visible flicker on every browser tab switch. Now tracks when the SSE connection was lost and only reloads history if disconnected for more than 10 seconds. Brief reconnects (tab visibility change, transient network blip) preserve the existing DOM and rely on the "Done without response" safety net for missed events. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gemini-code-assist

Code Review

This pull request optimizes the SSE reconnection process by only reloading chat history if the disconnection exceeds 10 seconds, reducing UI disruption for brief interruptions. The review feedback focuses on improving code maintainability by suggesting the use of a named constant for the 10-second threshold and consolidating the new _sseDisconnectedAt variable with the existing _connectionLostAt state to avoid redundancy and ensure consistent state management.

gemini-code-assist · 2026-04-13T16:52:07Z

 let _connectionLostAt = null;
 let _reconnectAttempts = 0;
 let _lastSseEventId = null;
+let _sseDisconnectedAt = null;


The introduction of _sseDisconnectedAt creates redundancy with the existing _connectionLostAt variable (line 224), which is also used to track disconnection timestamps in onerror.

Additionally, the 10-second threshold for history reload is a magic number that should be defined as a constant for better maintainability and consistency with other timeouts in this file (e.g., DONE_WITHOUT_RESPONSE_TIMEOUT_MS).

Suggested change

let _sseDisconnectedAt = null;

const SSE_RECONNECT_RELOAD_THRESHOLD_MS = 10000;

let _connectionLostAt = null;

gemini-code-assist · 2026-04-13T16:52:07Z

 // the 3rd tab exhausts the browser's per-origin limit.
 document.addEventListener('visibilitychange', () => {
  if (document.hidden) {
+    _sseDisconnectedAt = _sseDisconnectedAt || Date.now();


Consider reusing the existing _connectionLostAt variable instead of introducing _sseDisconnectedAt. Reusing the existing state tracker would simplify the logic and avoid having two variables tracking the same event (disconnection start).

Suggested change

_sseDisconnectedAt = _sseDisconnectedAt || Date.now();

_connectionLostAt = _connectionLostAt || Date.now();

gemini-code-assist · 2026-04-13T16:52:07Z

+      const disconnectMs = _sseDisconnectedAt ? Date.now() - _sseDisconnectedAt : 0;
+      if (disconnectMs > 10000) {
+        loadHistory();
+      }


Use the suggested constant SSE_RECONNECT_RELOAD_THRESHOLD_MS here to avoid magic numbers. Also, if you consolidate the variables as suggested, use _connectionLostAt here. Calculating the duration dynamically using Date.now() for the active disconnection period is consistent with the repository's approach to tracking durations of ongoing processes.

Suggested change

const disconnectMs = _sseDisconnectedAt ? Date.now() - _sseDisconnectedAt : 0;

if (disconnectMs > 10000) {

loadHistory();

}

const disconnectMs = _connectionLostAt ? Date.now() - _connectionLostAt : 0;

if (disconnectMs > SSE_RECONNECT_RELOAD_THRESHOLD_MS) {

loadHistory();

}

References

When calculating durations for ongoing tasks or states, calculate the duration dynamically using Date.now() for the part of the task that is still running.

gemini-code-assist · 2026-04-13T16:52:08Z

+        loadHistory();
+      }
    }
+    _sseDisconnectedAt = null;


If consolidating variables, ensure _connectionLostAt is reset here. Note that the existing reset at line 739 is wrapped in an if (lostBanner) block, which means it isn't always cleared on successful reconnection (e.g., for short disconnects where the banner timer never fired). Resetting it here ensures the state is always clean for the next disconnection.

Suggested change

_sseDisconnectedAt = null;

_connectionLostAt = null;

gemini-code-assist · 2026-04-13T16:52:08Z

  };

  eventSource.onerror = () => {
+    _sseDisconnectedAt = _sseDisconnectedAt || Date.now();


This assignment is redundant because _connectionLostAt is already being set with the same logic at line 783 (within the same onerror handler). Consolidating these into a single variable would improve clarity.

henrypark133

Review: SSE reconnect history reload time-gate (Risk: Low)

Clean fix. Tracks _sseDisconnectedAt to only reload full chat history when disconnected >10s. Brief reconnects (tab visibility change, transient blip) rely on SSE catch-up instead of full re-render — preserves scroll position and avoids disrupting the user.

Positives:

E2E tests updated to simulate the >10s disconnect condition
Both visibilitychange and onerror paths set the disconnect timestamp correctly
Reconnect banner logic simplified

LGTM.

henrypark133

No verified findings in the current head.

The reconnect path now only forces a full loadHistory() after a real disconnect window (>10s), which avoids the scroll-destructive reload on brief tab-hide and transient reconnects while still preserving the long-gap recovery path covered by the updated SSE tests.

henrypark133

Review: SSE reconnect history reload time-gate

No verified findings in the current diff.

The reconnect path now only forces a full loadHistory() after a real disconnect window, which preserves scroll position on brief tab-hide or transient reconnects while keeping the long-gap recovery path covered by the updated SSE test.

…itch regression test Address review feedback on #2415: - Remove the duplicate `_connectionLostAt` variable; `_sseDisconnectedAt` now tracks both tab-visibility and onerror disconnects, giving `onopen` a single source of truth and a single `loadHistory()` decision point. - Hoist the 10s threshold to a named `SSE_RELOAD_THRESHOLD_MS` constant. - Add `test_tab_switch_does_not_reload_chat_history` that drives the real `visibilitychange` handler and asserts no `/api/chat/history` call fires and the chat DOM survives — prevents silent reintroduction of #2404. - Pre-seed `_sseDisconnectedAt` in the server-restart test so it reliably exercises the history-reload path on hardware where the restart cycle completes inside the threshold window. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…h-chat-refresh # Conflicts: # crates/ironclaw_gateway/static/app.js

The new-thread helper only waited for `currentThreadId !== assistantThreadId`. When a prior test left the server's `active_thread` pointing at a user-created thread, the initial page load sets `currentThreadId` to that stale thread and the wait passes immediately — before `createNewThread()` resolves. The test then reads messages and sends a chat against the wrong thread, the new thread activates mid-flight and clears the DOM, and the `assistants.length > before` condition never fires. Factor the wait into `_create_new_user_thread`, capture the previous thread id, and require `currentThreadId` to change to a *new* non-assistant value. Apply to both refresh tests that had the pattern. Verified stable over 3 consecutive full-suite runs. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ilblackdragon · 2026-04-18T06:17:13Z

A number of flaky tests in Playwright - fixing them here as well, then approving.

test_refresh_skips_readonly_external_active_thread registers a `page.route("**/api/chat/threads", ...)` handler that fetches + rewrites the response. The frontend polls this endpoint periodically (especially on SSE reconnect), so a request is often in flight inside `patch_threads_response` when the `page` fixture closes the context. The cancelled `route.fetch()` surfaces on the *next* test's `Browser.new_context()` call as a TargetClosedError, flaking test_multiple_tabs_receive_same_response under full-suite load. Call `page.unroute_all(behavior="ignoreErrors")` at the end of the test so in-flight route callbacks are drained before teardown. Verified stable across 5 consecutive full-suite runs (was ~60% flake rate). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Tie the setup and teardown comments together so a future reader adding a similar route intercept understands the full context — why the fetch can be mid-flight at teardown, how the cancellation surfaces on an unrelated later test, and that pairing with unroute_all is mandatory. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…earai#2415) * fix(gateway): time-gate SSE reconnect history reload to prevent tab-switch flicker (nearai#2404) Every SSE reconnection unconditionally called loadHistory(), which clears the entire chat DOM and re-renders all messages — losing scroll position and causing visible flicker on every browser tab switch. Now tracks when the SSE connection was lost and only reloads history if disconnected for more than 10 seconds. Brief reconnects (tab visibility change, transient network blip) preserve the existing DOM and rely on the "Done without response" safety net for missed events. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: address review findings (iteration 1) Set _sseDisconnectedAt before server restart in E2E test to prevent flaky timeout when the restart completes in <10s. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

github-actions Bot added size: S 10-49 changed lines risk: low Changes to docs, tests, or low-risk modules contributor: core 20+ merged PRs labels Apr 13, 2026

gemini-code-assist Bot reviewed Apr 13, 2026

View reviewed changes

henrypark133 previously approved these changes Apr 14, 2026

View reviewed changes

serrrfirat dismissed henrypark133’s stale review via 647fe21 April 14, 2026 19:18

serrrfirat linked an issue Apr 15, 2026 that may be closed by this pull request

[QA] Dashboard keeps refreshing and wiping contents in a loop #2410

Closed

serrrfirat mentioned this pull request Apr 15, 2026

[QA] Dashboard keeps refreshing and wiping contents in a loop #2410

Closed

serrrfirat enabled auto-merge (squash) April 15, 2026 11:05

serrrfirat requested a review from henrypark133 April 15, 2026 11:15

henrypark133 previously approved these changes Apr 15, 2026

View reviewed changes

serrrfirat dismissed henrypark133’s stale review via 5b0b4a6 April 16, 2026 21:09

serrrfirat force-pushed the fix/2404-tab-switch-chat-refresh branch from fba8b59 to a00af6e Compare April 17, 2026 16:56

github-actions Bot added risk: low Changes to docs, tests, or low-risk modules and removed size: XS < 10 changed lines (excluding docs) risk: medium Business logic, config, or moderate-risk modules labels Apr 17, 2026

henrypark133 previously approved these changes Apr 17, 2026

View reviewed changes

ilblackdragon dismissed henrypark133’s stale review via 4e6da6e April 18, 2026 04:04

ilblackdragon and others added 2 commits April 18, 2026 04:18

Merge remote-tracking branch 'origin/staging' into fix/2404-tab-switc…

5ffa455

…h-chat-refresh # Conflicts: # crates/ironclaw_gateway/static/app.js

ilblackdragon approved these changes Apr 18, 2026

View reviewed changes

serrrfirat merged commit ab276eb into staging Apr 18, 2026
7 checks passed

serrrfirat deleted the fix/2404-tab-switch-chat-refresh branch April 18, 2026 06:45

github-actions Bot mentioned this pull request Apr 18, 2026

chore: promote staging to staging-promote/e3df3ec4-24598763826 (2026-04-18 07:25 UTC) #2627

Merged

henrypark133 mentioned this pull request Apr 21, 2026

chore: release #2606

Merged

Navigation Menu

fix(gateway): time-gate SSE reconnect history reload (#2404) - #2415

fix(gateway): time-gate SSE reconnect history reload (#2404)#2415
serrrfirat merged 6 commits into
stagingfrom
fix/2404-tab-switch-chat-refresh

serrrfirat commented Apr 13, 2026 •

edited

Loading

Uh oh!

gemini-code-assist Bot left a comment

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Uh oh!

henrypark133 left a comment

Uh oh!

henrypark133 left a comment

Uh oh!

henrypark133 left a comment

Uh oh!

ilblackdragon commented Apr 18, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

	let _sseDisconnectedAt = null;
	const SSE_RECONNECT_RELOAD_THRESHOLD_MS = 10000;
	let _connectionLostAt = null;

	_sseDisconnectedAt = _sseDisconnectedAt \|\| Date.now();
	_connectionLostAt = _connectionLostAt \|\| Date.now();

Conversation

serrrfirat commented Apr 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Changes

Test plan

Uh oh!

gemini-code-assist Bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Apr 13, 2026

Choose a reason for hiding this comment

Uh oh!

henrypark133 left a comment

Choose a reason for hiding this comment

Review: SSE reconnect history reload time-gate (Risk: Low)

Uh oh!

henrypark133 left a comment

Choose a reason for hiding this comment

Uh oh!

henrypark133 left a comment

Choose a reason for hiding this comment

Review: SSE reconnect history reload time-gate

Uh oh!

ilblackdragon commented Apr 18, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

serrrfirat commented Apr 13, 2026 •

edited

Loading