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refactor: restructured audit logic and render boundary tracking

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- Removed complex snapshot caching and volatile/stable state tracking logic.
- Replaced multi-zone audit logic with streamlined tail-sample checks.
- Simplified render boundaries by deriving a single final boundary from the live region.
- Eliminated redundant audit state management and auxiliary safe-end interfaces.
This commit is contained in:
can1357
2026-07-04 09:50:20 +02:00
parent b258c790a5
commit d5e9084e65
5 changed files with 230 additions and 721 deletions
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packages/coding-agent/src/modes/components/transcript-container.ts
+67 -412
View File
@@ -7,45 +7,6 @@ import {
type ViewportTailProvider,
} from "@oh-my-pi/pi-tui";
const kSnapshot = Symbol("transcript.liveDiffSnapshot");
/**
* Per-block render cache: the block's previous stripped contribution plus the
* derived append-only state. Still-live blocks use it as input to
* {@link deriveLiveCommitState}; finalized blocks wholly inside already
* committed native scrollback can replay it without calling render().
*/
interface LiveDiffSnapshot {
width: number;
lines: readonly string[];
generation: number;
appendOnly: boolean;
/**
* Frames remaining until a block that rewrote an interior row may re-earn
* append-only status. `0` means the block is not under rewrite suspicion.
*/
volatileCooldown: number;
/**
* Stable-prefix ratchet (see {@link deriveLiveCommitState}): leading rows
* promoted as commit-safe because they stayed visibly identical for
* {@link STABLE_PREFIX_COMMIT_FRAMES} consecutive frames, plus the in-flight
* candidate run and its age.
*/
stablePrefixLength: number;
candidatePrefixLength: number;
candidatePrefixAge: number;
/**
* Topmost row index ever observed rewritten in place (see
* {@link deriveLiveCommitState}): the stable-prefix ratchet never promotes
* rows at/after it. `Infinity` until the first rewrite.
*/
rewriteFloor: number;
}
interface SnapshotCarrier {
[kSnapshot]?: LiveDiffSnapshot;
}
/**
* A transcript block that is still mutating (a foreground tool awaiting its
* result, an assistant message mid-stream) reports `false` so the container
@@ -65,18 +26,20 @@ interface FinalizableBlock {
*/
getTranscriptBlockVersion?(): number;
/**
* Whether a still-live block's visually settled leading rows are durable —
* guaranteed to survive the block's remaining transitions (finalize,
* displacement) byte-stable — and may therefore be promoted as commit-safe
* by {@link deriveLiveCommitState}. Blocks whose pending render is
* provisional (a tool call's tail-window streaming preview, replaced
* wholesale by the result render) return `false`: committing such rows
* strands a stale copy in immutable terminal history the moment the real
* content re-lays-out the block (the engine audit recommits below it —
* "duplication, never loss"). Absent = `true`, the default for blocks
* whose live rows persist (a streaming assistant message).
* Leading rows of the block's current render() output that are declared
* FINAL while the block is still live: byte-stable at the current width
* until the block finalizes, monotone non-decreasing under streaming
* growth, re-derived per render (the container reads it right after
* calling render()). The container extends the native-scrollback commit
* boundary through these rows so a long streaming reply's scrolled-off
* head reaches terminal history mid-stream. Declaring a row that later
* changes strands a stale copy in immutable history (the engine audit
* repairs by recommitting below — duplication, never loss), so
* implementers report only rows whose bytes provably cannot change (e.g.
* rendered output of markdown's frozen token prefix). Absent = 0: nothing
* commits until the block finalizes.
*/
isTranscriptBlockCommitStable?(): boolean;
getTranscriptBlockSettledRows?(): number;
}
function isBlockFinalized(child: Component): boolean {
@@ -89,9 +52,12 @@ function getBlockVersion(child: Component): number | undefined {
return fn ? fn.call(child) : undefined;
}
function isBlockCommitStable(child: Component): boolean {
const fn = (child as Component & FinalizableBlock).isTranscriptBlockCommitStable;
return fn ? fn.call(child) : true;
/** Clamped read of a block's declared settled rows (see {@link FinalizableBlock}). */
function getBlockSettledRows(child: Component): number {
const fn = (child as Component & FinalizableBlock).getTranscriptBlockSettledRows;
if (!fn) return 0;
const value = fn.call(child);
return Number.isFinite(value) ? Math.max(0, Math.trunc(value)) : 0;
}
// A "plain blank" row is empty or whitespace-only with no ANSI bytes. It marks
@@ -143,270 +109,24 @@ const EMPTY_SEGMENTS: BlockSegment[] = [];
/** Shared empty result for an empty viewport-tail render (no allocation). */
const EMPTY_TAIL: readonly string[] = [];
interface LiveCommitState {
appendOnly: boolean;
volatileCooldown: number;
stablePrefixLength: number;
candidatePrefixLength: number;
candidatePrefixAge: number;
rewriteFloor: number;
safeLength: number;
}
/**
* Render frames a block must stay clean (static or append-shaped) after an
* interior rewrite before its rows become committable again. A one-off
* re-layout (a codespan finalizing across a wrap boundary, a paragraph
* re-parsed as a heading) only suspends commits briefly — the pinned emitter
* appends from the stalled high-water mark, so the gap backfills contiguously
* once the block re-earns append-only. Periodic animations (a spinner rewrites
* its row every few frames) keep resetting the countdown and never re-earn it,
* so genuinely volatile blocks stay deferred. Frames arrive at most at the
* TUI's 30 Hz render cadence, so 30 frames ≈ 1s of clean streaming.
*/
const VOLATILE_REARM_FRAMES = 30;
/**
* Consecutive frames a leading row run must stay visibly identical before it
* is promoted as commit-safe even though the block's tail keeps rewriting.
* Append-only detection alone is all-or-nothing per block: one perpetually
* ticking row (a task tool's progress tree, per-agent cost/tool counters, a
* log line spinner) suspends commits for the WHOLE block forever, so once the
* block outgrows the viewport its static head — e.g. a task's prompt/context
* markdown — is neither committed to native scrollback nor on screen: the
* transcript reads as cut off for the entire (possibly minutes-long) run.
* The ratchet commits the settled head while only the genuinely volatile tail
* stays deferred. If a promoted row is later rewritten (a collapsing
* preview), the engine's committed-prefix audit re-anchors and recommits —
* duplication, never loss — and the ratchet retreats to the divergence.
*/
const STABLE_PREFIX_COMMIT_FRAMES = 30;
/**
* Rows at a live block's tail treated as the volatile streaming edge. Real
* streaming is not strictly append-only at the bottom: the in-flight markdown
* paragraph re-wraps as words arrive (rewriting its last 1-2 visual rows), an
* unclosed token (`**bold`, a half-streamed link) re-renders when its closer
* arrives, and a wrap-shrink moves the last word onto a new row. Divergence
* confined to this zone is clean growth, and the zone itself is held back
* from the offered commit boundary — so a tolerated rewrite can never touch a
* row the engine may have committed. Width 4 covers the observed shapes (≤2
* rows) with margin for wide glyphs and multi-row token spans; the cost is
* only that the last 4 rows of a live block commit at finalization instead of
* mid-stream, which is invisible (they are on screen — the viewport is always
* taller than the holdback).
*/
const TAIL_VOLATILITY_ROWS = 4;
/**
* Visible-content form of a row: SGR/OSC bytes and trailing pad spaces are
* write framing, not content. A styled line's closing escape moves when the
* line stops being the last of its span (a wrapped thinking paragraph growing
* by one row), and width-padded rows shift their trailing spaces as text
* grows; both leave the on-screen cells identical and must not count as a
* rewrite of a committed-candidate row. Committed scrollback rows are written
* with a full SGR/OSC reset terminator, so escape-placement drift between
* visually identical renders cannot bleed styles across rows.
*/
function normalizeRow(line: string): string {
return Bun.stripANSI(line).trimEnd();
}
function rowsVisiblyEqual(prev: string, cur: string): boolean {
return prev === cur || normalizeRow(prev) === normalizeRow(cur);
}
/**
* Whether `cur` is `prev` grown in place: the visible content of `prev` is a
* strict-or-equal prefix of `cur`'s (token streaming appending to the cursor
* row). Escape placement and pad drift are ignored, same as rowsVisiblyEqual.
*/
function rowVisiblyGrew(prev: string, cur: string): boolean {
return normalizeRow(cur).startsWith(normalizeRow(prev));
}
function hasValidSnapshot(
snapshot: LiveDiffSnapshot | undefined,
width: number,
generation: number,
): snapshot is LiveDiffSnapshot {
return snapshot !== undefined && snapshot.generation === generation && snapshot.width === width;
}
function commonPrefixLength(prev: readonly string[], cur: readonly string[]): number {
const limit = Math.min(prev.length, cur.length);
let i = 0;
while (i < limit && rowsVisiblyEqual(prev[i]!, cur[i]!)) i++;
return i;
}
function commonSuffixLength(prev: readonly string[], cur: readonly string[], prefixLength: number): number {
const limit = Math.min(prev.length - prefixLength, cur.length - prefixLength);
let i = 0;
while (i < limit && rowsVisiblyEqual(prev[prev.length - 1 - i]!, cur[cur.length - 1 - i]!)) i++;
return i;
}
function deriveLiveCommitState(
previous: LiveDiffSnapshot | undefined,
current: readonly string[],
width: number,
generation: number,
): LiveCommitState {
let appendOnly = false;
let volatileCooldown = 0;
let stablePrefixLength = 0;
let candidatePrefixLength = 0;
let candidatePrefixAge = 0;
let rewriteFloor = Number.POSITIVE_INFINITY;
let trailingRowGrowth = false;
if (hasValidSnapshot(previous, width, generation)) {
appendOnly = previous.appendOnly;
volatileCooldown = previous.volatileCooldown;
stablePrefixLength = previous.stablePrefixLength;
candidatePrefixLength = previous.candidatePrefixLength;
candidatePrefixAge = previous.candidatePrefixAge;
rewriteFloor = previous.rewriteFloor;
const prefixLength = commonPrefixLength(previous.lines, current);
const staticRender = prefixLength === previous.lines.length && prefixLength === current.length;
let cleanFrame = true;
if (!staticRender) {
const suffixLength = commonSuffixLength(previous.lines, current, prefixLength);
// Append-only growth never rewrites a row that may already have scrolled
// into native scrollback; it only grows the block at/near its tail. Two
// shapes qualify:
// - a pure insertion that preserves every previous row across a
// matching prefix + suffix (a bottom append, or an insertion above
// stable trailing chrome like a streaming tool's footer/border);
// - a rewrite whose divergence BEGINS inside the trailing
// TAIL_VOLATILITY_ROWS of the previous render — the streaming edge:
// the in-flight paragraph re-wrapping as words arrive (its last 1-2
// visual rows), an unclosed markdown token (`**bold`) re-rendering
// when its closer streams in, a wrap-shrink pushing the last word
// onto an appended row. That zone is held back from `safeLength`
// below, so a tolerated rewrite can never touch a row that was
// offered for commit.
// The anchor matters: the gap must START in the tail zone, not merely
// be small — a one-row ticker mid-block with stable rows beneath it
// would otherwise classify clean, get offered past, and rewrite
// committed rows on every tick. Any deeper divergent row means the
// block re-laid-out committed-candidate content — a rewrite, which
// suspends commits until the block re-earns append-only.
const preservedEveryRow = prefixLength + suffixLength >= previous.lines.length;
const tailConfined = preservedEveryRow || prefixLength >= previous.lines.length - TAIL_VOLATILITY_ROWS;
if (tailConfined && current.length >= previous.lines.length) {
// Strict trailing-row growth: every previous row except the last
// is visibly unchanged and the last grew in place as a visible
// prefix, with no rows appended — a line accumulating tokens.
// The sole divergent row is the block's physical last row, which
// the engine's window floor never commits while it stays last
// (chunkTo ≤ windowTop ≤ last row index), so the volatile-tail
// holdback below is unnecessary: the whole body is offerable and
// the block's scrolled-off head reaches native scrollback.
trailingRowGrowth =
current.length === previous.lines.length &&
prefixLength === previous.lines.length - 1 &&
rowVisiblyGrew(previous.lines[prefixLength]!, current[prefixLength]!);
if (volatileCooldown === 0) appendOnly = true;
// Clean growth inserts/rewrites rows at the divergence; a floor
// inside the preserved suffix travels down with it, a floor at or
// above the divergent zone stays put (conservative: a stale floor
// index can only point at an earlier row, never a later one).
const delta = current.length - previous.lines.length;
if (delta > 0 && Number.isFinite(rewriteFloor)) {
const suffixStart = Math.max(prefixLength, previous.lines.length - suffixLength);
if (rewriteFloor >= suffixStart) rewriteFloor += delta;
}
} else {
cleanFrame = false;
appendOnly = false;
volatileCooldown = VOLATILE_REARM_FRAMES;
}
}
if (cleanFrame && volatileCooldown > 0) volatileCooldown--;
// Stable-prefix ratchet, independent of append-only. `prefixLength` is
// this frame's visibly-unchanged leading run; the candidate accumulates
// the MINIMUM prefix across a STABLE_PREFIX_COMMIT_FRAMES window, so
// promotion means every promoted row stayed identical for the whole
// window (row r is inside frame i's common prefix iff r < p_i, so
// r < min(p) holds for every frame of the window). A row settling
// mid-window promotes at most two windows later. The engine audit owns
// any promoted rows that already committed (recommit, never loss).
if (prefixLength < stablePrefixLength) {
// A divergence inside the promoted run is the ratchet's proof of
// over-promotion: this row was visibly stable for a full window,
// got promoted (and likely committed), and then mutated anyway — a
// slow ticker (an agent row's tool/cost counter, a growing progress
// tree), not settling content. It will mutate again, and every
// promote→mutate cycle makes the engine audit recommit, spraying a
// stale snapshot of the block into native scrollback. Floor the
// ratchet at the divergence permanently: rows above it may still
// promote, rows at/below it never re-promote while the block lives.
// One-off re-layouts before any promotion (a call→result frame
// transition, a codespan finalizing) never hit this branch, and the
// append-only re-arm path commits the full block regardless of the
// floor.
rewriteFloor = Math.min(rewriteFloor, prefixLength);
stablePrefixLength = prefixLength;
candidatePrefixLength = prefixLength;
candidatePrefixAge = 0;
} else {
candidatePrefixLength =
candidatePrefixAge === 0 ? prefixLength : Math.min(candidatePrefixLength, prefixLength);
candidatePrefixAge++;
if (candidatePrefixAge >= STABLE_PREFIX_COMMIT_FRAMES) {
// Cap at the volatile-tail holdback: a long static stretch would
// otherwise promote the streaming edge itself (min prefix == full
// length), and the next chunk's tail re-wrap would then rewrite
// offered rows.
stablePrefixLength = Math.min(
candidatePrefixLength,
rewriteFloor,
Math.max(0, current.length - TAIL_VOLATILITY_ROWS),
);
candidatePrefixLength = prefixLength;
candidatePrefixAge = 0;
}
}
}
return {
appendOnly,
volatileCooldown,
stablePrefixLength,
candidatePrefixLength,
candidatePrefixAge,
rewriteFloor,
// A clean-streaming block's body is committable up to the volatile-tail
// holdback (the streaming edge is never offered, so its tolerated
// rewrites can never touch committed rows); otherwise the settled head
// still is — only the volatile tail stays deferred. Strict in-place
// growth of the trailing row skips the holdback: its only mutable row
// is the block's last, which cannot commit while it remains last.
safeLength: appendOnly
? trailingRowGrowth
? current.length
: Math.max(stablePrefixLength, current.length - TAIL_VOLATILITY_ROWS, 0)
: stablePrefixLength,
};
}
/**
* Transcript container that renders every block's current content each frame
* and reports the live-region seam (`NativeScrollbackLiveRegion`) that gates
* the engine's append-only scrollback commits.
* and reports the native-scrollback commit boundary
* (`NativeScrollbackLiveRegion`): the frame row below which every rendered
* row is final. The boundary covers the leading run of finalized blocks plus
* the first still-live block's declared settled rows
* ({@link FinalizableBlock.getTranscriptBlockSettledRows}); the engine
* commits rows to native scrollback only above it.
*
* The engine never rewrites committed history: rows above the seam that have
* entered the tape keep whatever bytes they were committed with ("let the
* history be"), while the visible window always repaints from each block's
* latest render — a late tool result, a post-finalize error pin, or an expand
* toggle is always reflected on screen. Blocks that are still mutating (an
* unfinalized tool, a streaming assistant message) stay below the seam so
* their rows do not enter history while they can still change; a streaming
* block whose render grows append-only deepens the seam through its settled
* head so a long reply's scrolled-off rows still reach scrollback mid-stream.
* The engine never rewrites committed history: rows above the boundary that
* have entered the tape keep whatever bytes they were committed with ("let
* the history be"), while the visible window always repaints from each
* block's latest render — a late tool result, a post-finalize error pin, or
* an expand toggle is always reflected on screen. Blocks that are still
* mutating (an unfinalized tool, a streaming assistant message) stay at/below
* the boundary so their rows do not enter history while they can still
* change; when the live region outgrows the viewport its undeclared rows
* scroll into a deferred gap and reach history, in order, once they settle.
*
* Assembly is incremental: the returned array is persistent and mutated in
* place. Each block's render is still called every frame, but a block whose
@@ -420,29 +140,13 @@ export class TranscriptContainer
extends Container
implements NativeScrollbackLiveRegion, NativeScrollbackCommittedRows, RenderStablePrefix, ViewportTailProvider
{
// Bumped to retire every block's diff snapshot at once (theme change /
// clear); a snapshot is only honored when its stored generation matches.
// Bumped to retire every block segment at once (theme change / clear); a
// segment is only reused when its stored generation matches.
#generation = 0;
// Local line index where the current live region begins in the most recent
// render. TUI commits rows to native scrollback only above this seam (or
// the deeper commit-safe end below).
// Local line index below which every row of the most recent render is
// final: the leading finalized blocks plus the first live block's declared
// settled rows. TUI commits rows to native scrollback only above it.
#nativeScrollbackLiveRegionStart: number | undefined;
// Local line index up to which the leading run of live blocks is safe to
// commit. Finalized blocks contribute their full body; still-live blocks
// contribute only while their render has been observed growing without
// visibly rewriting a previously rendered interior row (escape placement
// and pad drift are ignored). A rewrite suspends the block's contribution
// until it re-earns append-only via VOLATILE_REARM_FRAMES clean frames;
// the engine then backfills the stalled gap.
#nativeScrollbackCommitSafeEnd: number | undefined;
// Local line index up to which the leading run of live blocks is DURABLE: a
// commit-stable block's full body is permanent content even while its interior
// rows re-lay-out (a streaming markdown table re-aligning columns), so the
// engine must append their scroll-off snapshot rather than drop it. Reported
// separately from the byte-stable commit-safe end because these rows may still
// drift after commit; the engine commits them audit-exempt. Provisional
// (commit-unstable) blocks never extend it.
#nativeScrollbackSnapshotSafeEnd: number | undefined;
// Persistent assembled transcript rows. Rows before the stable floor are
// byte-identical to the previous render; rows at/after it were re-pushed.
#lines: string[] = [];
@@ -483,14 +187,6 @@ export class TranscriptContainer
return this.#nativeScrollbackLiveRegionStart;
}
getNativeScrollbackCommitSafeEnd(): number | undefined {
return this.#nativeScrollbackCommitSafeEnd;
}
getNativeScrollbackSnapshotSafeEnd(): number | undefined {
return this.#nativeScrollbackSnapshotSafeEnd;
}
/**
* Whether `component` sits below a still-mutating block — i.e. inside the
* live region, where its rows cannot have been committed to native
@@ -581,21 +277,21 @@ export class TranscriptContainer
override render(width: number): readonly string[] {
width = Math.max(1, width);
this.#nativeScrollbackLiveRegionStart = undefined;
this.#nativeScrollbackCommitSafeEnd = undefined;
this.#nativeScrollbackSnapshotSafeEnd = undefined;
const count = this.children.length;
// The live region spans from the earliest still-mutating block through the
// bottom. A block that has not finalized must stay below the seam: out-of-
// band inserts (TTSR/todo cards) can append a finalized block *below* a
// tool that is still awaiting its result, and committing the tool there
// would strand its history rows on the mid-stream preview the late result
// never reaches.
let liveStartIndex = count - 1;
// The commit boundary stops at the earliest still-mutating block. A
// block that has not finalized must gate it: out-of-band inserts
// (TTSR/todo cards) can append a finalized block *below* a tool that is
// still awaiting its result, and committing rows there would strand the
// tool's history rows on a mid-stream preview the late result never
// reaches.
let liveStartIndex = -1;
let hasLiveBlock = false;
for (let i = 0; i < count; i++) {
if (!isBlockFinalized(this.children[i]!)) {
liveStartIndex = i;
hasLiveBlock = true;
break;
}
}
@@ -621,19 +317,11 @@ export class TranscriptContainer
// invariant — otherwise re-pushed rows land after the stale frame.
if (!chainStable) lines.length = 0;
// Tracks whether we are still inside the leading run of commit-safe live
// blocks. The first still-live volatile block closes it, but rendering
// continues so lower blocks remain visible.
let commitSafeOpen = true;
// The live-region start is recorded at the first visible row at/after
// liveStartIndex; empty leading blocks (or a separator) must not claim it
// early.
let liveRecorded = false;
// Frame row cursor: rows emitted (reused or pushed) so far.
let row = 0;
let stableRows = 0;
for (let i = 0; i < count; i++) {
const child = this.children[i]! as Component & SnapshotCarrier;
const child = this.children[i]!;
// This child's contribution: its current render with plain-blank
// top/bottom edges stripped (the container owns inter-block gaps).
@@ -642,7 +330,6 @@ export class TranscriptContainer
// immutable terminal history for the current width/generation. Blocks
// outside committed history still render normally so late results,
// post-finalize re-layouts, and expand toggles remain visible.
const previousSnapshot = child[kSnapshot];
const previous = previousSegments[i];
const finalized = isBlockFinalized(child);
const version = getBlockVersion(child);
@@ -674,33 +361,15 @@ export class TranscriptContainer
previous.width === width &&
previous.generation === this.#generation);
const contribution = reusable ? previous.contribution : stripPlainBlankEdges(raw);
let liveCommitState: LiveCommitState | undefined;
// Provisional live renders (commit-unstable blocks) never feed the
// promotion machinery: their settled-looking rows are replaced
// wholesale on finalize, so offering them would commit a stale
// preview the result render can only duplicate, never erase.
if (i >= liveStartIndex && !finalized && isBlockCommitStable(child)) {
liveCommitState = deriveLiveCommitState(previousSnapshot, contribution, width, this.#generation);
}
// Cache the latest contribution as the next frame's diff input.
child[kSnapshot] = {
width,
lines: contribution,
generation: this.#generation,
appendOnly: liveCommitState?.appendOnly ?? false,
volatileCooldown: liveCommitState?.volatileCooldown ?? 0,
stablePrefixLength: liveCommitState?.stablePrefixLength ?? 0,
candidatePrefixLength: liveCommitState?.candidatePrefixLength ?? 0,
candidatePrefixAge: liveCommitState?.candidatePrefixAge ?? 0,
rewriteFloor: liveCommitState?.rewriteFloor ?? Number.POSITIVE_INFINITY,
};
// Empty (or stripped-to-nothing) children contribute nothing and never
// affect spacing or the live-region offsets. An empty still-live child
// still closes the commit-safe run: if it later gains rows, it pushes
// affect spacing. An empty still-live child still gates the commit
// boundary at its position: if it later gains rows, it pushes
// everything below it.
if (contribution.length === 0) {
if (i >= liveStartIndex && commitSafeOpen && !finalized) commitSafeOpen = false;
if (hasLiveBlock && i === liveStartIndex) {
this.#nativeScrollbackLiveRegionStart = row;
}
if (chainStable && !(reusable && previous.rowCount === 0 && previous.startRow === row)) {
chainStable = false;
lines.length = row;
@@ -729,11 +398,19 @@ export class TranscriptContainer
const sep = row > 0 && !isPlainBlank(lines[row - 1]!) ? 1 : 0;
// The separator before the first live block stays in the committed
// prefix (it is deterministic once the prior block's body is settled),
// so the live region begins at the block's first content row.
if (!liveRecorded && i >= liveStartIndex) {
this.#nativeScrollbackLiveRegionStart = row + sep;
liveRecorded = true;
// prefix (it is deterministic once the prior block's body is
// settled); the boundary then extends through the live block's
// declared settled rows, mapped from its raw render into the
// stripped contribution.
if (hasLiveBlock && i === liveStartIndex) {
let settled = 0;
const settledRaw = getBlockSettledRows(child);
if (settledRaw > 0) {
let lead = 0;
while (lead < raw.length && isPlainBlank(raw[lead]!)) lead++;
settled = Math.max(0, Math.min(contribution.length, settledRaw - lead));
}
this.#nativeScrollbackLiveRegionStart = row + sep + settled;
}
const rowCount = sep + contribution.length;
@@ -749,28 +426,6 @@ export class TranscriptContainer
for (let j = 0; j < contribution.length; j++) lines.push(contribution[j]!);
}
const blockStart = row + sep;
if (i >= liveStartIndex && commitSafeOpen) {
const safeLength = finalized ? contribution.length : (liveCommitState?.safeLength ?? 0);
if (safeLength > 0) {
this.#nativeScrollbackCommitSafeEnd = blockStart + safeLength;
}
// Durable snapshot end: a commit-stable block's whole body is durable
// content — its scrolled-off rows are permanent even while interior
// rows re-lay-out (a streaming table re-aligning columns), so the
// engine must commit their snapshot on scroll-off rather than drop it.
// Finalized blocks are wholly durable; provisional (commit-unstable)
// blocks offer nothing beyond their byte-stable safe length.
const snapshotLength = finalized || isBlockCommitStable(child) ? contribution.length : safeLength;
if (snapshotLength > 0) {
this.#nativeScrollbackSnapshotSafeEnd = blockStart + snapshotLength;
}
// A finalized, fully safe block may let the contiguous safe run extend
// into blocks rendered below it. A still-live block keeps pushing lower
// rows around as it grows, so the run closes there.
if (!(finalized && safeLength >= contribution.length)) commitSafeOpen = false;
}
segments[i] = {
component: child,
rawRef: raw,