Hidden panes are exempt from pendingData flow control (main gate-drops
their bytes after ingestion), so N background agents ran unbounded ahead
on the one shared daemon->main stream socket (measured 192MB user-space
backlog) and visible-pane echo waited FIFO behind it — typing appeared
seconds late whenever several agents burst on a loaded machine
(8x512KB/s + 12 CPU spinners: p50 293ms fix-off; 12x1MB/s: 6.1s).
Mechanism (replaces producer pacing — no reveal catch-up, ever):
- Shallow socket write gate (128KB) + per-session fairness bypass bounds
echo latency by construction; kernel-flush refill sentinel keeps held
bulk draining at full speed (drain-only refill capped at ~8MB/s).
- Backgrounded sessions' queued output is keep-tail dropped (newest
512KB kept, in-order dataGap replaces the middle); a ~2MB GLOBAL
budget shrinks per-session keep-tails (floor 64KB) so a worktree
switch never waits behind the aggregate. Reply-eliciting query bytes
(DSR/DA/OSC probes) are salvaged from dropped spans.
- Notifications are structurally lossless: the daemon runs the same
shared scanners main uses (bell/OSC 133/pr-link/2031) over every byte
BEFORE drop decisions and relays facts in byte order; ordered
background markers hand scan authority back and forth, seeded with the
emulator's partial escape tail so a sequence split across the handoff
neither phantom-fires nor goes missing. Titles/agent-status stay
main-side (kept-tail convergent).
- Main: background = hidden AND no remote view subscriber (a live
mobile/web view is never thinned); on dataGap main resets cross-chunk
parse carries, drops the headless mobile mirror, and reuses the
hidden-drop model-restore marker.
Wire: three new stream events, tolerated within protocol v19 (old mains
ignore unknown events; old daemons never see the trigger). Kill
switches: ORCA_DAEMON_BACKGROUND_STREAM_DROP=0,
ORCA_DAEMON_SHALLOW_SOCKET_GATE=0.
A/B (pnpm bench:multi-workspace-typing): 8x512KB/s + 12 CPU workers
p50 293ms/p90 647ms -> 15/21ms (= baseline); 12x1MB/s 6,146ms -> 20ms;
light loads unchanged; zero missing echoes. Latin hidden-restore e2e
green (probe-verified aggregate-drain root cause). New deterministic
repro harness: tests/e2e/terminal-multi-workspace-typing-latency.spec.ts
+ CPU pressure workers.
Co-authored-by: Orca <help@stably.ai>
Every field report of the frozen-terminal family so far has needed
follow-up asks (console output, main logs, second snapshots) because each
capture showed one process's counters at one instant. This makes a single
DevTools command sufficient: `await window.__orcaTerminalFreezeReport()`
returns renderer state (document.visibilityState + the stale-visibility
override, pty:data listener count, delivery-watchdog totals), main's debug
snapshot extended with a per-pty delivery table (sent/acked/pending, hidden
vs visible-set membership, last send/ACK ages, window focus flags, power
suspend/resume ages, app version), and bounded breadcrumb rings from BOTH
processes recording the transitions that matter: gate marks/unmarks,
visibilitychange and stale-visibility latches, watchdog stalls and heals,
restore markers, heal write-offs, and renderer lifecycle resets (so "user
already reloaded" is visible in the history).
Costs stay off the data path: breadcrumbs record only rare transitions into
a 100-entry ring with same-kind coalescing (a flood costs one slot per
second); the per-pty table is built only when the snapshot is read; the
per-send bookkeeping adds one Date.now() to existing accounting writes. Pty
ids are redacted to their `@@` suffix because daemon session ids embed
worktree paths. The report assembles over invoke IPC — the direction proven
alive in every observed wedge — and a failing invoke is captured as data
instead of sinking the report.
The stuck-occlusion e2e now also pins the report end-to-end: after the
wedge + keystroke recovery, the report must carry the stale-visibility
latch and gate transitions in the renderer ring, gate-mark/unmark in main's
ring, and a populated per-pty table. Suites: pty.test.ts 258, terminal-pane
1705, shared ring 5; typing-latency perf gate passes.
Co-authored-by: Orca <help@stably.ai>
macOS occlusion tracking can wedge document.visibilityState at 'hidden'
after display sleep and never fire another visibilitychange. The hidden-
delivery gate then keeps dropping renderer-bound bytes for panes the user
is looking at (field snapshot 2026-07-06, v1.4.124-rc.2.perf: 78MB dropped
across 2 pane-level-visible ptys with a fully healthy transport), and every
recovery path (window focus, system-resume relay, backlog recovery) re-ran
syncHiddenRendererPtyDelivery only to recompute the same stale predicate —
nothing could ever clear the gate. The user sees a frozen terminal; typing
echo is dropped in main; only a reload recovers.
Real user input while the document claims hidden is a physical
contradiction: keystrokes and clicks only reach a focused, on-screen
window. stale-document-visibility.ts latches that proof, runs each pane's
existing visibilitychange resync (gate unhide + hidden-output snapshot
restore), and hands authority back to the occlusion tracker on the next
genuine visibilitychange. No timers; the failure bias is safe — a wrong
latch can only restore pre-gate delivery cost, never drop bytes. Hot path
unchanged: the foreground predicate still returns on the same single
comparison while the document is visible.
tests/e2e/terminal-stuck-occlusion-recovery.spec.ts pins the wedge
(visibilityState pinned hidden -> output dropped, not painted; the
hiddenDeliveryGatedVisiblePtyCount field discriminator reads >0) and the
recovery (one Shift keypress repaints the missed output from the main-owned
snapshot, no reload, while visibilityState still reads hidden). Negative
control verified: the spec fails without this fix. Typing-latency perf
gate passes; terminal-pane unit suites 366/366.
Co-authored-by: Orca <help@stably.ai>
74 commits from main, including the STA-1278 ai-vault transcript perf work,
terminal flicker fix (#7540), renderer V8 heap raise (#7531), scrollbar
position preservation (#7472), and the per-delivery debug-snapshot
allocation removal (#7541).
Conflict resolutions (our structure, main's semantics):
- agent-detection: kept the split-module barrel; grafted main's Gemini/Pi
title-detection refinements (path-fragment false positives, legacy Pi
synthetic titles) into agent-title-core, dropped the superseded
PI_IDLE_PREFIX.
- orca-runtime wait-blocked detection: kept the throttled
scheduleWaitBlockedCheck (branch §1 optimization) and ported it to main's
new cached TerminalTailWaitState API; main's per-chunk cached scan stays
on the leaf mismatch path where it auto-merged. pty.tailWaitState is
deliberately never populated on this branch (throttle owns the pty
record), so the leaf mirror copy invalidates rather than shares — the
fromTail exactness contract is never violated by stale state.
- recordPtyRendererDeliveryPressure: took main's allocation-free peak
update (#7541) and derived per-pty in-flight from this branch's
cumulative sent/acked accounting instead of the removed
rendererInFlightCharsByPty map.
- rpc/methods/terminal detach: kept both sides — our
flushAllAckPendingOutput and main's exitWaiterAbort release.
- pty-connection: kept our single-policy handleCommandFinished (invariant)
alongside main's new sampleVisiblePaneForegroundAgent (bodies were
byte-identical where they overlapped).
- e2e pressure scenarios: kept the Phase-4 hidden-gate contract assertions
and the extracted pressure-script module; adopted main's
MAX_WORST_KEY_LATENCY_UNDER_LOAD_MS budget.
Also documents the renderer-pull delivery watchdog in the branch guide.
Gates: typecheck clean; ipc/daemon/terminal-pane/pane-manager suites 4256
passed; both fuzz suites pass.
Co-authored-by: Orca <help@stably.ai>
Main inlined an OSC 133 parser with new 133;C onCommandStarted support;
our branch parses via the shared scanner so main-side side-effect facts
stay byte-identical. Resolution keeps the shared-scanner architecture and
adds 133;C to it; the foreground-agent tracker hooks into the branch's
single handleCommandFinished policy (bytes and sideEffect facts alike).
Co-authored-by: Orca <help@stably.ai>
Bug D: the serialized screen cannot carry the VT100 DECSC saved-cursor
register, so a hidden ESC 7 followed by a post-reveal ESC 8 restored to
home and clobbered live cells. The snapshot epilogue now re-saves at the
source's saved position before the final absolute CUP
(readSavedCursorRegister + serializeWithAbsoluteCursor; the active
buffer's own register, so alt screens carry theirs). Position-only by
design; never-saved terminals are left untouched.
Bug E: a PTY read ending mid-escape leaves the sequence in the emulator's
parser, so serialize dropped it and the racing tail's continuation bytes
rendered literally after reveal (~24% of the fuzz corpus). The emulator
now tracks the unparsed trailing partial at ingest
(terminal-partial-escape-tail.ts, committed post-parse like the mouse
mirror) and ships it as TerminalSnapshot.pendingEscapeTailAnsi.
applyMainBufferSnapshot writes it LAST, after POST_REPLAY reset — any
later ESC would abort the dangling sequence. Seq accounting is unchanged:
the tail is a suffix of bytes the snapshot seq already counts, so
reconcile slicing needs no adjustment.
Fuzz suites: unskip the Bug B/C repros (fixed on this branch) and the new
D/E repros; remove the B/C/E tolerance predicates so regressions fail
loudly. Only Bug A (upstream wrap null-cell) stays tolerated + counted.
Green at FUZZ_ITERATIONS=2000 (fidelity) and 1000 (reconciliation).
Co-authored-by: Orca <help@stably.ai>
- Fidelity suite: add snapshotHasSelfCancellingBoldReset (Bug B) and
isMarginWrapPendingCursorOffByOne (Bug C) predicates so the corpus tolerates +
counts them like Bug A. FUZZ_ITERATIONS=2000 is now green (~113s) and fails
only on genuinely new divergences; each tolerance keeps its <50% degeneracy
guard. Default 300 unchanged (~17s).
- Reconciliation suite: drop SGR 7 (inverse) from the append-only tail. Inverse
marks trailing blanks with an inverse-fg the serializer round-trips slightly
differently by capture depth — a Bug-B-class serialize nuance, not seq
reconciliation. FUZZ_ITERATIONS=1000 is now green; default 200 unchanged.
- Notes updated: every bug class is both pinned (skipped repro) and tolerated in
its corpus; combined default runtime ~19s.
Regex uses String.fromCharCode(27) to stay oxlint no-control-regex clean.
Co-authored-by: Orca <help@stably.ai>
Property-tests the reveal seq-reconciliation byte-stitch (getChunkDataAfterSnapshot
/ reconcileChunkAgainstRestoredSnapshot in pty-connection.ts), mirrored exactly:
N=200 seeded hide/reveal scenarios with a rich agent-TUI hidden prefix snapshot
and an append-only racing tail, chunked with seq/rawLength meta, seq-domain
restarts, unmetered chunks and droppedOutput markers. Asserts snapshot-at-S +
reconciled tail == snapshot-of-everything (seq-neutral) and == always-visible
(end-to-end). Runtime ~5s at 200; FUZZ_ITERATIONS override documented.
Two NEW real snapshot-limitation garbles found while building it, both distinct
from suite 1's serialize bugs and pinned as standalone it.skip repros:
- Bug D: the DECSC saved-cursor register is not serialized. A hidden TUI that
saves the cursor (ESC 7 / CSI s) and restores it on reveal (ESC 8 / CSI u)
lands the restore at home. Repro: 'AB\x1b7\x1b[4;10HCD' + '\x1b8X' -> 'XB' vs 'ABX'.
- Bug E: a snapshot taken mid-escape-sequence (a PTY read split an escape) drops
the partial sequence (it's parser state, not buffer), so the tail's
continuation renders literal. Repro: 'AB\x1b[3' + 'mCD' -> 'ABmCD' vs 'ABCD'.
Fired on ~24% of the corpus (tolerated + counted via prefixEndsMidSequence).
The append-only-tail design isolates seq reconciliation from these and the Bug C
cursor cascade. Full evidence + fix directions in notes. No production changes.
Co-authored-by: Orca <help@stably.ai>
Scanned seeds 1..2000. Beyond the pre-documented serialize wrap-null-cell bug
(A, 27 seeds, tolerated), the fuzz surfaced two NEW real @xterm/addon-serialize
0.15.0-beta.287 round-trip defects, both of which garble a revealed hidden pane:
- Bug B (seeds 435, 770, 1321): serializing a dim cell followed by a bold-only
cell emits \x1b[1;22m; SGR 22 clears bold too, so restored bold is lost.
Minimal repro: '\x1b[2mA\x1b[22m\x1b[1mB' -> restored 'B' loses bold.
- Bug C (seeds 454, 1696): a final content row filled to the right margin leaves
xterm wrap-pending; the serializer's relative cursor restore lands one column
short. Minimal repro: '0123456789\x1b[3;5H' at cols=10 -> cursor x=3 not x=4.
Both isolated to pure serializer replay (no Orca preamble), confirming upstream.
Parity fixture verified faithful to the renderer pane's buffer options. Each is
pinned as a standalone it.skip repro; full evidence + classification in
notes/garble-fuzz-divergences.md. Seed 113 (handoff's DECSC/DECRC case) does not
diverge on the current harness. No production code changed.
Co-authored-by: Orca <help@stably.ai>
Conflict resolutions:
- terminal-stream-protocol: Metadata keeps opcode 12 (shipped to mobile
in v1.4.120); branch-only Ack renumbers to 13.
- scheduler: keep HIGH_PRIORITY_MAX_WRITES_PER_DRAIN=8 (perf fix) over
main's 2 (#7139 landed there with the old constant).
- headless-emulator: keep chain structure (scanner classes, query-reply
forwarding); graft main's pathFlavor/remotePosixFileUriAuthority OSC7
options through TerminalOscCwdTitleScanner. Main's
TerminalPrivateModeTracker is logic-identical to the chain's
TerminalMouseModeMirror (kept, with pre-filter).
- orca-runtime: keep chain factory; graft main's pathFlavor wiring and
snapshot cwd fallback; keep both teardown lines.
- pty-connection: keep both chain reconcile and main's ordered-seq
tracking; clear the chain's restored-snapshot baseline on pty exit
(same seq-domain boundary main's reset enforces) — fixes revive with
restarted seq counter dropping chunks as duplicates.
- subscribe-buffer tests: updated to merged semantics — main's inline
overflow recovery ships current data as the FIRST snapshot; the
chain's resized/pending-output-overflow follow-up remains as backstop.
Validation: typecheck clean; 7,548 tests green across daemon/ipc/
runtime/pane-manager/terminal-pane/shared/mobile-transport (1 documented
pre-existing WSL failure).
Co-authored-by: Orca <help@stably.ai>
Jinwoo-HandOrca
Jinwoo Hong