fix(fetch): settle bounded post-load render work

[lanyue-llk]

A page can dispatch Load before an already queued first render turn mounts its visible application content. Native Markdown then snapshots the complete documentation shell but misses live tables or other content produced by that immediate render chain.

This change adds one bounded owner command after Load/Done. It consumes only the current document’s already queued animation frame and one-shot zero-delay timer work, including each task’s normal microtask checkpoint. It stops after 20 ms or 16 turns. Intervals, future business timers, idle callbacks, internal timers, and URL-specific rules remain outside the completion boundary.

The behavior test mounts a table through Load → requestAnimationFrame → setTimeout(0) → microtask. A five-second fallback and a repeating zero-delay interval verify that background work does not hold the result open. The tests run through the repository CI.

PR stack

GitHub dependency chain:

#1334 → #1335 → #1336 → #1337 → #1380 → #1428 → #1431 → #1432

This PR targets codex/risk011-navigation-handoff, the head branch of #1431. Its Files changed view therefore contains only this bounded post-load render fix. Merge the stack from left to right. #919 is a separate historical combination and is not a dependency. #1429 targets main independently because it only adds reusable comparison CI.

[github-actions]

Sequential Navigation Soak A/B

✅ HEAD completed the 200-navigation resilience and memory observation.

One browser process, one target, and one CDP session navigate CSDN → SegmentFault → Huaban → example.com repeatedly. This run issued 200 Page.navigate commands per binary.

Common ancestor ff4656e4db → HEAD 1d827c9408; benchmark order: head-first; workflow: success.

Session resilience

Metric	Base	HEAD
Attempted / planned	200 / 200	200 / 200
Direct observable pass	199 / 200	199 / 200
Failures / recovered	1 / 1	1 / 1
Recovery failures	0	0
Lifecycle order violations	0	0
Network order violations	0	0
Wall time	483.2 s	468.8 s

A public-page failure is reported separately from an unrecoverable session. The soak requires all navigation attempts, zero failed recovery, zero lifecycle/network ordering violations, and complete resource evidence.

Process-tree memory

Metric	Base	HEAD	Δ
Boundary samples	200	200	0
Boundary RSS samples	200	200	0
Boundary PSS samples	200	200	0
Periodic peak RSS	266.3 MiB	267.4 MiB	+1.1 MiB
Periodic peak PSS	263.6 MiB	263.7 MiB	+0.1 MiB
RSS · first 10 avg	180.9 MiB	185.1 MiB	+4.1 MiB
RSS · last 10 avg	194.2 MiB	188.9 MiB	-5.3 MiB
RSS · last − first window	+13.3 MiB	+3.8 MiB	-9.5 MiB
RSS · warm slope / 100 nav	+6.0 MiB	+3.7 MiB	-2.2 MiB
PSS · first 10 avg	177.3 MiB	181.5 MiB	+4.2 MiB
PSS · last 10 avg	191.1 MiB	185.3 MiB	-5.9 MiB
PSS · last − first window	+13.8 MiB	+3.8 MiB	-10.0 MiB
PSS · warm slope / 100 nav	+6.5 MiB	+3.8 MiB	-2.7 MiB
Peak file descriptors	63	62	-1
Peak threads	31	31	0

HEAD memory by 50-navigation quarter

HEAD range	Avg RSS	Final RSS	Peak RSS	Avg PSS	Final PSS	Peak FD
1–50	180.3 MiB	159.6 MiB	231.5 MiB	176.7 MiB	156.1 MiB	54
51–100	190.9 MiB	180.0 MiB	232.2 MiB	187.1 MiB	176.4 MiB	54
101–150	192.2 MiB	170.9 MiB	234.7 MiB	188.6 MiB	167.4 MiB	52
151–200	191.3 MiB	182.4 MiB	231.1 MiB	187.6 MiB	178.8 MiB	61

Raw reports and per-navigation boundary samples: workflow run and full sequential-navigation-soak-results artifact.

Public-site timing and memory are observational. Use the A/B deltas and trend shape as evidence, not as a deterministic performance threshold.

[github-actions]

CI Regression Report

Source CI run · source state at render: in_progress · artifacts: 6/6

Check	Status	Signal
Release regression	✅	HEAD/base failures 0/0; raw binary +0.003169%
Frontend differential	✅	1,020/1,020 cases matched; 0 issues
Agent episodes	✅	8/8 Moli episodes passed; 0 failures
Runtime/CDP contracts	✅	26 contract cases; 0 failures
CDP smoke	✅	52/52 groups passed; 621 scenarios
WebMainBench	✅	545/545 completed; 0 unexpected failures

Release regression — ✅ HEAD/base failures 0/0; raw binary +0.003169%

Package and image size

Metric	Base	HEAD	Delta	Delta %
Raw binary	149.02 MiB	149.03 MiB	+4.84 KiB	+0.003169%
Stripped binary	102.65 MiB	102.66 MiB	+4.00 KiB	+0.003805%
gzip binary	51.15 MiB	51.15 MiB	+1.50 KiB	+0.002860%
Rootfs	155.93 MiB	155.93 MiB	0 B	0.00%
gzip rootfs	60.04 MiB	60.05 MiB	+5.41 KiB	+0.008804%

Startup latency and PSS

Case	Base p50	HEAD p50	Delta	Base PSS	HEAD PSS	Delta
Serve ready	27.44 ms	16.14 ms	−11.29 ms	3.30 MiB	6.98 MiB	+3.68 MiB
CDP first page	49.99 ms	58.09 ms	+8.10 ms	3.69 MiB	7.67 MiB	+3.99 MiB
CDP warm page	12.10 ms	14.55 ms	+2.45 ms	49.86 MiB	49.22 MiB	−663.00 KiB
CLI about:blank	15.78 ms	20.43 ms	+4.65 ms	2.82 MiB	3.99 MiB	+1.17 MiB
CLI local JS	20.28 ms	23.31 ms	+3.02 ms	3.76 MiB	3.31 MiB	−453.00 KiB

Concurrency matrix

Concurrency	Base p50	HEAD p50	Delta	Base PSS	HEAD PSS	Delta	HEAD failures	Unstable B/H
1	23.54 ms	22.77 ms	−0.77 ms	466.00 KiB	455.00 KiB	−11.00 KiB	0	0/0
5	36.56 ms	32.69 ms	−3.87 ms	6.92 MiB	10.32 MiB	+3.41 MiB	0	0/0
10	30.09 ms	31.74 ms	+1.65 ms	11.90 MiB	11.58 MiB	−330.25 KiB	0	0/0
25	34.59 ms	32.91 ms	−1.69 ms	5.74 MiB	9.30 MiB	+3.56 MiB	0	0/0
100	31.95 ms	31.79 ms	−0.15 ms	10.03 MiB	11.49 MiB	+1.46 MiB	0	0/0

Frontend differential — ✅ 1,020/1,020 cases matched; 0 issues

Match	DOM mismatch	Diagnostic mismatch	Moli error	Reference error	Infrastructure error	Mismatched frames	Duration
1,020	0	0	0	0	0	0	6m 44.07s

Agent episodes · Moli vs Chromium — ✅ 8/8 Moli episodes passed; 0 failures

Fast contract	Episodes	Passed	Assertions	Ready p50	Episode p50
Moli	8	8	47/47	3.34 ms	25.96 ms
Chromium	8	8	47/47	271.83 ms	83.78 ms

Operation p50	Chromium	Moli	Delta	Delta %
navigate	42.65 ms	8.97 ms	−33.68 ms	−78.96%
observe	0.77 ms	0.87 ms	+0.10 ms	+13.20%
fill	3.76 ms	3.55 ms	−0.22 ms	−5.78%
click	4.83 ms	4.15 ms	−0.68 ms	−14.14%

Idle-resource episode	Peak RSS	Peak PSS	Average CPU	Peak CPU	Peak processes	Sampler
Moli	65.50 MiB	62.91 MiB	0.77%	9.99%	1	✅
Chromium	1279.96 MiB	409.79 MiB	2.04%	97.83%	13	⚠️ PSS partial

Runtime and CDP session contracts — ✅ 26 contract cases; 0 failures

Suite	Cases	Failures	Median case p50	Median case p95	Median peak PSS p50
Synthetic fetch	13	0	18.15 ms	18.56 ms	626.00 KiB
Long-lived CDP session	13	0	18.21 ms	18.80 ms	—

CDP smoke — ✅ 52/52 groups passed; 621 scenarios

Workers: 4 · cumulative group time: 192.27 s · failed groups: 0

Slowest group	Scenarios	Duration	Status
scrollbar-visibility	22	28.55 s	✅
target-lifecycle	24	16.98 s	✅
dom-input	27	13.47 s	✅
multi-page	45	11.23 s	✅
chromium-cdp	56	11.10 s	✅

WebMainBench · 545 pages — ✅ 545/545 completed; 0 unexpected failures

Completed	Successful	Expected DNS failure	Unexpected failures	Panics	Crashes	Timeouts	Empty output
545/545	544	1	0	0	0	0	0

Frozen HTML · Linux · --wait done · 45 seconds per page · no retries. Content quality is evaluated separately.

Diagnostics: webmainbench-results — every page's Markdown, stderr, and exit status. Source run and artifacts

All artifact fields are parsed by the trusted default-branch renderer; missing or invalid inputs remain visible as unavailable.

[github-actions]

Spider Bench A/B

✅ All benchmark browser service runs completed; results are informational.

Public HEAD: 184 / 240 rows; 38 / 48 sites produced rows; 10 unexpected empty sites.

✅ Deterministic fixture contract is clean.

Common ancestor ff4656e4db09 → HEAD 1d827c940866; benchmark order: head-first; workflow: success.

Public 48-site run · informational

Metric	Base	HEAD	Δ
Run status	success	success	—
Extracted rows / contract	184 / 240	184 / 240	0 (0.00%)
Contract fill	76.67%	76.67%	0.00 pp (0.00%)
Sites with rows	38 / 48	38 / 48	0 (0.00%)
Sites meeting row contract	36 / 48	36 / 48	0 (0.00%)
Unexpected empty sites	10	10	0 (0.00%)
Partial-row sites	2	2	0 (0.00%)
Site outcomes	extracted: 37; HTTP error + rows: 1; empty: 7; HTTP error + empty: 1; snapshot error + empty: 2	extracted: 36; HTTP error + rows: 2; empty: 7; HTTP error + empty: 1; snapshot error + empty: 2	—
Observed duration	52.19 s	56.53 s	+4.34 s (+8.32%)
Estimated CPU	54.10 s	51.26 s	-2.85 s (-5.26%)
Peak PSS	272.04 MiB	280.62 MiB	+8.57 MiB (+3.15%)
Peak RSS	274.98 MiB	284.89 MiB	+9.91 MiB (+3.60%)
Peak threads	26	27	+1 (+3.85%)
Mismatched sites	0	0	0
Timeout with items	0	0	0

Category rows	Base	HEAD	Δ
news	35 / 40	35 / 40	0
stocks	20 / 40	20 / 40	0
tech	35 / 40	35 / 40	0
sports	27 / 40	27 / 40	0
games	37 / 40	37 / 40	0
life	30 / 40	30 / 40	0

Public-site content, timing, and memory are noisy. This single A/B run reports evidence only; site outcome counts explain missing rows without treating them as a deterministic regression.

CPU and memory timelines

These are bounded 40-point views of the same complete process-tree samples used by the HTML report. CPU uses 100% per occupied logical core; memory lines are RSS first and PSS second when complete PSS samples are available.

Base

xychart-beta
    title "Base CPU"
    x-axis "Elapsed seconds" [1.585, 3.086, 4.587, 6.09, 7.593, 9.094, 10.095, 11.597, 13.099, 14.602, 16.104, 17.605, 18.605, 19.106, 20.607, 22.108, 23.611, 25.114, 26.616, 27.617, 28.617, 29.117, 30.62, 32.122, 33.625, 35.127, 36.629, 38.131, 39.633, 41.134, 42.637, 44.139, 45.14, 46.642, 48.144, 49.646, 51.149, 51.65]
    y-axis "CPU percent" 0 --> 500
    line [117.85, 42.01, 123.95, 153.66, 165.62, 82.01, 171.82, 95.77, 69.92, 143.8, 127.65, 4, 0, 5.99, 124.06, 21.98, 173.77, 127.62, 153.88, 139.85, 108.03, 105.96, 137.79, 161.59, 111.78, 6, 145.94, 107.91, 95.98, 143.84, 141.63, 15.98, 11.99, 55.92, 111.86, 47.95, 123.79, 197.52]

Loading

xychart-beta
    title "Base memory: RSS then PSS"
    x-axis "Elapsed seconds" [0.083, 1.585, 3.086, 4.587, 6.09, 7.593, 9.094, 10.095, 11.597, 13.099, 14.602, 16.104, 17.605, 18.605, 19.106, 20.607, 22.108, 23.611, 25.114, 26.616, 27.617, 28.617, 29.117, 30.62, 32.122, 33.625, 35.127, 36.629, 38.131, 39.633, 41.134, 42.637, 44.139, 45.14, 46.642, 48.144, 49.646, 51.149, 51.65, 52.186]
    y-axis "Memory MiB" 0 --> 500
    line [12.46, 114.11, 130.24, 137.53, 165.19, 161.28, 176.05, 181.28, 167.02, 164.95, 182.46, 162.1, 149.45, 147.92, 148.13, 175.43, 142.68, 168.46, 199.8, 190.26, 159.82, 274.98, 219.25, 205, 231.55, 159.71, 163, 176.56, 158.57, 165.77, 197.35, 251.57, 184.39, 169.21, 170.22, 183.92, 158.03, 180.57, 203.51, 0]
    line [9.26, 110.51, 126.65, 133.91, 162.15, 157.62, 172.37, 176.15, 163.35, 161.27, 178.82, 158.43, 145.78, 144.25, 144.46, 171.77, 139.01, 164.91, 196.15, 186.6, 156.15, 272.04, 215.21, 201.4, 227.87, 155.9, 159.33, 172.9, 154.89, 162.07, 193.34, 247.91, 180.69, 165.51, 166.51, 180.22, 154.3, 176.97, 199.86, 0]

Loading

HEAD

xychart-beta
    title "HEAD CPU"
    x-axis "Elapsed seconds" [1.541, 3.044, 4.545, 5.545, 6.046, 8.047, 9.548, 11.051, 12.553, 14.056, 15.56, 17.062, 19.174, 20.676, 22.677, 24.179, 25.682, 27.183, 27.684, 28.684, 30.185, 31.688, 33.189, 34.69, 36.693, 38.195, 39.696, 41.199, 42.7, 44.201, 45.702, 47.205, 48.705, 50.708, 52.211, 53.714, 55.216, 56.217]
    y-axis "CPU percent" 0 --> 500
    line [63.84, 125.78, 113.96, 183.77, 153.9, 163.99, 155.7, 155.55, 131.62, 141.8, 107.88, 109.91, 57.89, 15.99, 0, 43.95, 129.87, 103.87, 105.75, 114.05, 129.88, 11.98, 0, 123.85, 129.82, 103.9, 65.95, 113.74, 141.84, 100.01, 15.98, 0, 4, 4, 127.79, 59.88, 107.85, 202]

Loading

xychart-beta
    title "HEAD memory: RSS then PSS"
    x-axis "Elapsed seconds" [0.039, 1.541, 3.044, 4.545, 5.545, 6.046, 8.047, 9.548, 11.051, 12.553, 14.056, 15.56, 17.062, 19.174, 20.676, 22.677, 24.179, 25.682, 27.183, 27.684, 28.684, 30.185, 31.688, 33.189, 34.69, 36.693, 38.195, 39.696, 41.199, 42.7, 44.201, 45.702, 47.205, 48.705, 50.708, 52.211, 53.714, 55.216, 56.217, 56.527]
    y-axis "Memory MiB" 0 --> 500
    line [12.57, 94.12, 137.13, 133.62, 148.96, 167.92, 169.77, 178, 174.16, 185.75, 182.65, 169.55, 153.64, 160.3, 146.16, 146.58, 157.97, 161.06, 231.44, 284.89, 197.27, 186.11, 167.31, 165.13, 158.91, 171.25, 154.25, 149.39, 190.23, 247.02, 192.95, 165.18, 163.82, 163.82, 163.82, 190.25, 152.29, 175.71, 205.51, 0]
    line [9.24, 90.4, 133.51, 129.93, 145.22, 165.2, 165.84, 174.36, 170.58, 181.87, 178.82, 165.62, 149.74, 156.42, 142.31, 142.77, 154.21, 157.35, 227.72, 280.62, 193.58, 182.47, 163.58, 161.39, 155.17, 167.59, 150.52, 145.61, 186.68, 243.31, 189.21, 161.45, 160.09, 160.09, 160.09, 186.56, 148.57, 171.99, 201.83, 0]

Loading

Deterministic fixture · required contract

The fixture exercises 15 routes: 8 are expected to emit rows and 7 intentionally exercise empty, loading, or timeout behavior.

Metric	Base	HEAD	Δ
Run status	success	success	—
Extracted rows / contract	40 / 40	40 / 40	0 (0.00%)
Contract fill	100.00%	100.00%	0.00 pp (0.00%)
Sites with rows	8 / 15	8 / 15	0 (0.00%)
Sites meeting row contract	15 / 15	15 / 15	0 (0.00%)
Unexpected empty sites	0	0	0
Partial-row sites	0	0	0
Site outcomes	extracted: 7; HTTP error + rows: 1; empty: 3; timeout + empty: 4	extracted: 7; HTTP error + rows: 1; empty: 3; timeout + empty: 4	—
Observed duration	20.30 s	19.97 s	-0.33 s (-1.62%)
Estimated CPU	0.63 s	0.53 s	-0.10 s (-15.53%)
Peak PSS	66.63 MiB	66.55 MiB	-0.07 MiB (-0.11%)
Peak RSS	70.36 MiB	70.19 MiB	-0.17 MiB (-0.24%)
Peak threads	18	18	0 (0.00%)
Mismatched sites	0	0	0
Timeout with items	0	0	0

Full HTML, JSON, CSV, logs, and page snapshots: workflow run and full spider-bench-results artifact.

The public-web A/B is informational. The exact HEAD fixture contract runs as a separate required CI check; timing and public-site content deltas remain non-blocking.

[lanyue-llk]

Closing after the consolidation audit. A fixed 20 ms / 16-task post-load drain has no stable product completion meaning and is intentionally excluded from #1501.