After a hidden interval that added persisted messages (post-turn bg-review
writes, sibling-tab writes, the just-finished main turn flushing), switching
the tab back caused refreshActiveSessionIfExternallyUpdated('visible'|'focus')
to hit remoteCount !== localCount and call loadSession(sid, {force:true}),
which synchronously did S.messages = [] before awaiting the metadata +
messages fetches. The visible result was the entire conversation transcript
blanking for the round-trip and reappearing — '对话突然消失，重刷才回来'.
sessions.js itself warns about this 'disappear and reappear' tradeoff at the
top of the remoteCount/remoteLast guard, but only short-circuits the
metadata-only branch (#5061). #5122's 4-probe staged reconnect covers a
different path (SSE error with ready_state=2 on a visible tab) and does not
apply when the SSE error arrives while visibility_state='hidden' — that
bottoms out through _deferStreamErrorIfPageHidden before the reconnect block
ever runs.
Fix:
- refreshActiveSessionIfExternallyUpdated maps the visibility/focus recovery
reasons ({visible, focus}) to a new keepStaleUntilLoaded option, forwarded
to loadSession. The post-stream idle reconcile and the poll/external paths
keep their existing behaviour.
- loadSession ANDs opts.keepStaleUntilLoaded with sameSessionForceReload (so
cross-session switches still clear synchronously — leaving a prior
session's transcript on screen during a navigation is the original bug
the clear was written for) and, on that path, skips the synchronous
S.messages/S.toolCalls/_messagesTruncated/_oldestIdx clear. The new
transcript is SWAPPED into S.messages by _ensureMessagesLoaded(sid,
{force:true}), so the user sees old DOM directly replaced by new DOM in a
single render frame.
- _ensureMessagesLoaded grows an opts.force escape hatch so its 'messages
already populated' early-return cannot skip the swap when stale messages
are still in place.
Verified live on a source 8701 build:
- before: minHtmlObserved 65874, minKidsObserved 11 — 372 samples at 16ms,
DOM html length NEVER dipped below the pre-call value during the reload.
- loadSession was called with force:true keepStale:true reason:'visible',
outcome 'reloaded', sMsgs 21 → 1037, after kids 11 → 134 (single-frame
swap).
Tests:
- tests/test_issue5177_hidden_tab_blank_gap.py (new, 7 cases): source-locks
the keep-stale guard shape, the recovery-reason map, the
_ensureMessagesLoaded opts.force escape hatch, and that the synchronous
clear is wrapped in if(!_keepStaleUntilLoaded).
- Updated the two existing source-lock tests whose anchor strings included
the loadSession call signature
(tests/test_webui_external_refresh_frontend.py +
tests/test_tars_scroll_reset_regressions.py) to match the new
loadSession(... keepStaleUntilLoaded:_keepStaleUntilLoaded) form. No
behavioural assertions changed.
Local: node --check static/sessions.js OK. 122 passed across
test_issue5177_hidden_tab_blank_gap.py + the full adjacent set
(external-refresh / journal-frontend / scroll-reset / reconnect-chronology /
inflight-stream-reuse / sse-error-multi-probe / issue4295 / issue4856).
"Reply with selection" no longer appends the selected text straight into
the composer. It now adds a named chip ("Context N") to a row above the
message box (composerSelectionChips). Chips can be renamed (double-click,
esc()-escaped) or removed (x); multiple stack. On send(),
_flushSelectionBlocksToComposer() materializes pending blocks into the
composer as **Name:** + markdown-quoted text, then the normal send path
runs unchanged on composer.value.
Regression-safety:
- _flushSelectionBlocksToComposer early-returns when no blocks are pending,
so send() is byte-identical for anyone who never uses the feature.
- loadSession() AND newSession() both clear pending blocks before replacing
S.session, so chips never leak across a sidebar switch OR a New Chat
(the New Chat clear + its regression test were added per Codex review).
- chip name/text rendered via esc(); XSS-safe.
Verified live (headless CDP drive): add/render/remove/rename, flush
produces correct markdown, empty-flush no-op, session-switch clears,
injected <img onerror=...> chip-name escaped (not executed).
Co-authored-by: Rod Boev <rod.boev@gmail.com>
test_issue3306 _load_session_clear_block (4000->6500) + test_issue_new_chat_draft_restore
body window (4000->6500): #3899's idle-reset + live-turn-snapshot blocks pushed the
carry-forward snapshot + destructive S.messages clear past the old fixed windows. Behavior
+ ordering unchanged; windows widened to contain them.
