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[ai] Fix WorkflowChatTransport blocking browser paint during stream reconnect#1529

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[ai] Fix WorkflowChatTransport blocking browser paint during stream reconnect#1529
VaguelySerious merged 2 commits into
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peter/issue-1465

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@VaguelySerious VaguelySerious commented Mar 26, 2026

Summary

Closes #1465

  • iteratorToStream's pull() method now yields to the macrotask queue (setTimeout(0)) after each enqueue, giving the browser a chance to paint between chunks
  • This fixes the 7-8 second blank screen on page reload when WorkflowChatTransport replays buffered stream data on reconnect
  • Adds test coverage for iteratorToStream and streamToIterator

Test plan

  • New unit tests for iteratorToStream (macrotask yield, abort signal, error propagation)
  • New unit tests for streamToIterator
  • Existing WorkflowChatTransport tests pass
  • Typecheck passes
  • Manual: clone vercel/workflow-examples → flight-booking-app, send a message, wait for response, reload — messages should render progressively instead of all at once after ~7-8s

🤖 Generated with Claude Code

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Latest commit: 0a58e81

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📊 Benchmark Results

📈 Comparing against baseline from main branch. Green 🟢 = faster, Red 🔺 = slower.

workflow with no steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 0.043s (-8.7% 🟢) 1.005s (~) 0.962s 10 1.00x
💻 Local Nitro 0.048s (+10.2% 🔺) 1.006s (~) 0.958s 10 1.11x
🐘 Postgres Nitro 0.067s (-7.5% 🟢) 1.012s (-0.9%) 0.945s 10 1.56x
🐘 Postgres Express 0.073s (+20.9% 🔺) 1.022s (+1.1%) 0.949s 10 1.70x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 0.777s (+51.3% 🔺) 2.705s (-0.7%) 1.928s 10 1.00x
▲ Vercel Nitro 0.787s (+41.5% 🔺) 2.759s (+16.5% 🔺) 1.972s 10 1.01x

🔍 Observability: Express | Nitro

workflow with 1 step

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 1.129s (~) 2.006s (~) 0.877s 10 1.00x
💻 Local Nitro 1.133s (+0.6%) 2.006s (~) 0.872s 10 1.00x
🐘 Postgres Nitro 1.147s (~) 2.011s (~) 0.864s 10 1.02x
🐘 Postgres Express 1.156s (+1.5%) 2.013s (~) 0.857s 10 1.02x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.030s (-1.6%) 3.954s (+6.5% 🔺) 1.923s 10 1.00x
▲ Vercel Express 2.261s (+6.8% 🔺) 3.982s (+3.3%) 1.721s 10 1.11x

🔍 Observability: Nitro | Express

workflow with 10 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 10.894s (~) 11.025s (~) 0.131s 3 1.00x
🐘 Postgres Express 10.898s (~) 11.031s (~) 0.133s 3 1.00x
💻 Local Express 10.921s (~) 11.023s (~) 0.102s 3 1.00x
💻 Local Nitro 10.941s (~) 11.023s (~) 0.082s 3 1.00x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 16.883s (-5.5% 🟢) 18.441s (-3.5%) 1.558s 2 1.00x
▲ Vercel Express 17.052s (-2.3%) 18.773s (~) 1.720s 2 1.01x

🔍 Observability: Nitro | Express

workflow with 25 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 14.595s (+0.6%) 15.026s (~) 0.430s 4 1.00x
🐘 Postgres Express 14.648s (+1.0%) 15.031s (~) 0.383s 4 1.00x
💻 Local Express 14.897s (-0.6%) 15.028s (~) 0.131s 4 1.02x
💻 Local Nitro 14.972s (+0.6%) 15.030s (~) 0.058s 4 1.03x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 34.294s (+8.1% 🔺) 37.312s (+13.3% 🔺) 3.018s 2 1.00x
▲ Vercel Express 34.517s (+10.5% 🔺) 37.453s (+14.2% 🔺) 2.936s 2 1.01x

🔍 Observability: Nitro | Express

workflow with 50 sequential steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 13.976s (+1.3%) 14.165s (+1.0%) 0.190s 7 1.00x
🐘 Postgres Express 14.355s (+3.1%) 15.029s (+6.1% 🔺) 0.673s 6 1.03x
💻 Local Express 16.396s (-1.3%) 17.028s (~) 0.633s 6 1.17x
💻 Local Nitro 16.675s (+2.2%) 17.031s (~) 0.356s 6 1.19x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 57.067s (-2.9%) 59.350s (-2.0%) 2.283s 2 1.00x
▲ Vercel Nitro 58.897s (-4.4%) 61.925s (-2.5%) 3.028s 2 1.03x

🔍 Observability: Express | Nitro

Promise.all with 10 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.276s (+1.6%) 2.011s (~) 0.735s 15 1.00x
🐘 Postgres Nitro 1.279s (+1.1%) 2.012s (~) 0.733s 15 1.00x
💻 Local Express 1.515s (+2.7%) 2.005s (~) 0.490s 15 1.19x
💻 Local Nitro 1.521s (+1.4%) 2.006s (~) 0.484s 15 1.19x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 2.622s (+6.8% 🔺) 4.426s (+10.2% 🔺) 1.803s 7 1.00x
▲ Vercel Nitro 3.386s (+43.0% 🔺) 5.128s (+32.0% 🔺) 1.741s 6 1.29x

🔍 Observability: Express | Nitro

Promise.all with 25 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 2.338s (~) 3.011s (~) 0.673s 10 1.00x
🐘 Postgres Express 2.350s (+1.2%) 3.010s (~) 0.659s 10 1.01x
💻 Local Express 2.832s (-5.5% 🟢) 3.007s (-10.0% 🟢) 0.175s 10 1.21x
💻 Local Nitro 2.940s (+1.4%) 3.341s (+7.5% 🔺) 0.401s 9 1.26x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 3.539s (+36.9% 🔺) 4.973s (+22.5% 🔺) 1.434s 8 1.00x
▲ Vercel Nitro 4.120s (+58.6% 🔺) 5.808s (+51.1% 🔺) 1.687s 7 1.16x

🔍 Observability: Express | Nitro

Promise.all with 50 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 3.468s (~) 4.013s (~) 0.545s 8 1.00x
🐘 Postgres Express 3.478s (~) 4.014s (~) 0.536s 8 1.00x
💻 Local Express 7.814s (-3.1%) 8.019s (-8.6% 🟢) 0.204s 4 2.25x
💻 Local Nitro 8.101s (~) 9.024s (+2.9%) 0.923s 4 2.34x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 3.246s (+15.2% 🔺) 4.727s (+16.5% 🔺) 1.481s 7 1.00x
▲ Vercel Express 3.286s (+11.7% 🔺) 4.751s (~) 1.465s 7 1.01x

🔍 Observability: Nitro | Express

Promise.race with 10 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.256s (~) 2.009s (~) 0.754s 15 1.00x
🐘 Postgres Nitro 1.271s (+1.4%) 2.009s (~) 0.738s 15 1.01x
💻 Local Nitro 1.533s (+1.2%) 2.006s (~) 0.473s 15 1.22x
💻 Local Express 1.596s (+3.8%) 2.072s (+3.3%) 0.476s 15 1.27x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.408s (+18.0% 🔺) 4.408s (+21.3% 🔺) 2.000s 7 1.00x
▲ Vercel Express 2.482s (+16.4% 🔺) 4.452s (+11.5% 🔺) 1.970s 7 1.03x

🔍 Observability: Nitro | Express

Promise.race with 25 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 2.331s (~) 3.011s (~) 0.680s 10 1.00x
🐘 Postgres Express 2.347s (+1.3%) 3.012s (~) 0.665s 10 1.01x
💻 Local Nitro 3.061s (~) 3.886s (+3.4%) 0.825s 8 1.31x
💻 Local Express 3.064s (+2.0%) 3.564s (+3.2%) 0.501s 9 1.31x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.757s (+20.5% 🔺) 4.344s (+26.3% 🔺) 1.587s 7 1.00x
▲ Vercel Express 2.992s (+30.1% 🔺) 4.509s (+16.1% 🔺) 1.517s 7 1.09x

🔍 Observability: Nitro | Express

Promise.race with 50 concurrent steps

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 3.478s (~) 4.012s (~) 0.534s 8 1.00x
🐘 Postgres Express 3.482s (+0.6%) 4.011s (~) 0.529s 8 1.00x
💻 Local Nitro 8.676s (+2.8%) 9.026s (~) 0.350s 4 2.49x
💻 Local Express 8.940s (+2.2%) 9.522s (+5.5% 🔺) 0.582s 4 2.57x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 2.981s (+7.2% 🔺) 4.607s (+3.2%) 1.626s 7 1.00x
▲ Vercel Nitro 3.232s (+13.9% 🔺) 5.091s (+21.5% 🔺) 1.859s 6 1.08x

🔍 Observability: Express | Nitro

workflow with 10 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.831s (+1.1%) 1.024s (~) 0.194s 59 1.00x
🐘 Postgres Express 0.839s (+3.7%) 1.007s (~) 0.169s 60 1.01x
💻 Local Express 0.969s (-2.1%) 1.057s (-8.5% 🟢) 0.088s 57 1.17x
💻 Local Nitro 0.999s (+4.5%) 1.338s (+28.8% 🔺) 0.339s 45 1.20x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 9.278s (-5.4% 🟢) 11.672s (-0.6%) 2.393s 6 1.00x
▲ Vercel Express 9.354s (-3.0%) 11.031s (-4.4%) 1.677s 6 1.01x

🔍 Observability: Nitro | Express

workflow with 25 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.933s (+2.7%) 2.152s (+6.0% 🔺) 0.219s 42 1.00x
🐘 Postgres Nitro 1.982s (+5.8% 🔺) 2.378s (+15.8% 🔺) 0.396s 38 1.03x
💻 Local Express 2.966s (-0.9%) 3.257s (-3.6%) 0.291s 28 1.53x
💻 Local Nitro 3.064s (+4.1%) 4.011s (+30.5% 🔺) 0.947s 23 1.58x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 28.784s (-11.7% 🟢) 31.038s (-9.0% 🟢) 2.254s 3 1.00x
▲ Vercel Express 29.249s (-3.5%) 31.849s (-1.2%) 2.600s 3 1.02x

🔍 Observability: Nitro | Express

workflow with 50 sequential data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 4.003s (+4.1%) 4.405s (+9.0% 🔺) 0.402s 28 1.00x
🐘 Postgres Nitro 4.060s (+5.7% 🔺) 4.781s (+19.2% 🔺) 0.722s 26 1.01x
💻 Local Express 9.008s (-0.8%) 9.478s (-0.8%) 0.470s 13 2.25x
💻 Local Nitro 9.137s (+2.4%) 9.710s (+5.0% 🔺) 0.573s 13 2.28x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 79.993s (-87.4% 🟢) 81.877s (-87.2% 🟢) 1.884s 2 1.00x
▲ Vercel Express 84.856s (+5.0% 🔺) 86.671s (+4.6%) 1.815s 2 1.06x

🔍 Observability: Nitro | Express

workflow with 10 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 0.287s (+5.2% 🔺) 1.008s (~) 0.722s 60 1.00x
🐘 Postgres Nitro 0.298s (+7.0% 🔺) 1.008s (~) 0.710s 60 1.04x
💻 Local Express 0.596s (-0.7%) 1.004s (~) 0.409s 60 2.08x
💻 Local Nitro 0.618s (+5.2% 🔺) 1.022s (+1.7%) 0.404s 59 2.15x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 1.694s (-5.3% 🟢) 3.184s (-10.7% 🟢) 1.490s 20 1.00x
▲ Vercel Express 1.695s (+0.6%) 3.399s (+2.2%) 1.704s 18 1.00x

🔍 Observability: Nitro | Express

workflow with 25 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 0.506s (+3.0%) 1.008s (~) 0.502s 90 1.00x
🐘 Postgres Nitro 0.517s (+3.9%) 1.008s (~) 0.491s 90 1.02x
💻 Local Express 2.526s (+1.2%) 3.009s (~) 0.483s 30 4.99x
💻 Local Nitro 2.560s (+4.5%) 3.009s (~) 0.448s 30 5.06x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 2.654s (-7.0% 🟢) 4.437s (+2.9%) 1.783s 21 1.00x
▲ Vercel Express 2.897s (+4.1%) 4.536s (-2.4%) 1.638s 20 1.09x

🔍 Observability: Nitro | Express

workflow with 50 concurrent data payload steps (10KB)

💻 Local Development

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.779s (+0.9%) 1.016s (+0.8%) 0.238s 119 1.00x
🐘 Postgres Express 0.788s (+2.7%) 1.009s (~) 0.220s 119 1.01x
💻 Local Nitro 11.004s (+1.2%) 11.760s (+2.4%) 0.756s 11 14.13x
💻 Local Express 11.189s (+1.4%) 11.758s (+0.8%) 0.570s 11 14.37x

▲ Production (Vercel)

World Framework Workflow Time Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 6.377s (-21.7% 🟢) 8.015s (-16.2% 🟢) 1.639s 16 1.00x
▲ Vercel Express 6.652s (-8.7% 🟢) 8.170s (-8.7% 🟢) 1.518s 15 1.04x

🔍 Observability: Nitro | Express

Stream Benchmarks (includes TTFB metrics)
workflow with stream

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
💻 Local 🥇 Express 0.199s (-4.8%) 1.003s (~) 0.011s (-1.7%) 1.017s (~) 0.818s 10 1.00x
🐘 Postgres Nitro 0.202s (-1.6%) 0.995s (~) 0.001s (+7.7% 🔺) 1.011s (~) 0.809s 10 1.02x
💻 Local Nitro 0.210s (+5.0% 🔺) 1.004s (~) 0.011s (+7.5% 🔺) 1.018s (~) 0.808s 10 1.06x
🐘 Postgres Express 0.218s (+9.6% 🔺) 0.996s (+0.6%) 0.002s (+7.1% 🔺) 1.011s (~) 0.793s 10 1.10x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 1.630s (+4.1%) 2.453s (-5.3% 🟢) 0.739s (+40.5% 🔺) 3.819s (+4.9%) 2.189s 10 1.00x
▲ Vercel Express 1.660s (+3.4%) 2.627s (-1.3%) 0.708s (+25.1% 🔺) 3.937s (~) 2.277s 10 1.02x

🔍 Observability: Nitro | Express

stream pipeline with 5 transform steps (1MB)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Nitro 0.607s (+3.0%) 1.002s (~) 0.004s (-5.7% 🟢) 1.023s (~) 0.416s 59 1.00x
🐘 Postgres Express 0.615s (+3.2%) 1.003s (~) 0.004s (~) 1.024s (~) 0.409s 59 1.01x
💻 Local Nitro 0.732s (+2.8%) 1.010s (~) 0.010s (+6.4% 🔺) 1.024s (~) 0.291s 59 1.21x
💻 Local Express 0.748s (+3.0%) 1.009s (~) 0.009s (-2.4%) 1.024s (~) 0.276s 59 1.23x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 4.029s (-5.9% 🟢) 5.061s (-7.1% 🟢) 0.394s (+76.4% 🔺) 6.233s (-2.2%) 2.204s 10 1.00x
▲ Vercel Express 4.104s (+3.5%) 5.096s (-4.5%) 0.473s (+118.1% 🔺) 6.212s (-0.7%) 2.108s 10 1.02x

🔍 Observability: Nitro | Express

10 parallel streams (1MB each)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 0.975s (+4.0%) 1.163s (-6.3% 🟢) 0.000s (+223.1% 🔺) 1.203s (-4.5%) 0.227s 52 1.00x
🐘 Postgres Nitro 0.981s (+1.7%) 1.218s (-1.9%) 0.000s (-34.7% 🟢) 1.234s (-2.1%) 0.252s 49 1.01x
💻 Local Nitro 1.257s (+3.8%) 2.022s (~) 0.000s (-46.2% 🟢) 2.025s (~) 0.768s 30 1.29x
💻 Local Express 1.296s (+3.0%) 2.021s (~) 0.000s (~) 2.024s (~) 0.728s 30 1.33x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Express 2.613s (-4.6%) 3.516s (-3.0%) 0.000s (NaN%) 4.343s (+1.0%) 1.730s 14 1.00x
▲ Vercel Nitro 2.752s (-6.0% 🟢) 3.794s (+3.2%) 0.000s (~) 4.449s (+0.9%) 1.697s 14 1.05x

🔍 Observability: Express | Nitro

fan-out fan-in 10 streams (1MB each)

💻 Local Development

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
🐘 Postgres 🥇 Express 1.773s (+3.5%) 2.099s (~) 0.000s (~) 2.124s (~) 0.351s 29 1.00x
🐘 Postgres Nitro 1.781s (+2.6%) 2.138s (-1.3%) 0.000s (+3.6%) 2.152s (-1.4%) 0.371s 28 1.00x
💻 Local Nitro 3.539s (~) 4.031s (~) 0.001s (+57.1% 🔺) 4.036s (~) 0.496s 15 2.00x
💻 Local Express 3.589s (~) 4.098s (~) 0.001s (~) 4.103s (~) 0.515s 15 2.02x

▲ Production (Vercel)

World Framework Workflow Time TTFB Slurp Wall Time Overhead Samples vs Fastest
▲ Vercel 🥇 Nitro 3.578s (-4.0%) 4.874s (-0.6%) 0.000s (-100.0% 🟢) 5.518s (~) 1.940s 12 1.00x
▲ Vercel Express 3.580s (-77.3% 🟢) 4.612s (-72.9% 🟢) 0.001s (+Infinity% 🔺) 5.334s (-69.9% 🟢) 1.754s 12 1.00x

🔍 Observability: Nitro | Express

Summary

Fastest Framework by World

Winner determined by most benchmark wins

World 🥇 Fastest Framework Wins
💻 Local Express 14/21
🐘 Postgres Nitro 13/21
▲ Vercel Nitro 15/21
Fastest World by Framework

Winner determined by most benchmark wins

Framework 🥇 Fastest World Wins
Express 🐘 Postgres 16/21
Nitro 🐘 Postgres 17/21
Column Definitions
  • Workflow Time: Runtime reported by workflow (completedAt - createdAt) - primary metric
  • TTFB: Time to First Byte - time from workflow start until first stream byte received (stream benchmarks only)
  • Slurp: Time from first byte to complete stream consumption (stream benchmarks only)
  • Wall Time: Total testbench time (trigger workflow + poll for result)
  • Overhead: Testbench overhead (Wall Time - Workflow Time)
  • Samples: Number of benchmark iterations run
  • vs Fastest: How much slower compared to the fastest configuration for this benchmark

Worlds:

  • 💻 Local: In-memory filesystem world (local development)
  • 🐘 Postgres: PostgreSQL database world (local development)
  • ▲ Vercel: Vercel production/preview deployment
  • 🌐 Turso: Community world (local development)
  • 🌐 MongoDB: Community world (local development)
  • 🌐 Redis: Community world (local development)
  • 🌐 Jazz: Community world (local development)

📋 View full workflow run

❌ Some benchmark jobs failed:

  • Local: success
  • Postgres: success
  • Vercel: failure

Check the workflow run for details.

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🧪 E2E Test Results

❌ Some tests failed

Summary

Passed Failed Skipped Total
✅ ▲ Vercel Production 846 0 67 913
✅ 💻 Local Development 818 0 178 996
✅ 📦 Local Production 818 0 178 996
✅ 🐘 Local Postgres 818 0 178 996
✅ 🪟 Windows 75 0 8 83
❌ 🌍 Community Worlds 131 58 24 213
✅ 📋 Other 207 0 42 249
Total 3713 58 675 4446

❌ Failed Tests

🌍 Community Worlds (58 failed)

mongodb (2 failed):

  • hookWorkflow is not resumable via public webhook endpoint | wrun_01KMPTQ7B8ZXKAXGC1669DYWB5
  • concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KMPTZSSWMHQ0YM018475YE4A

redis (2 failed):

  • hookWorkflow is not resumable via public webhook endpoint | wrun_01KMPTQ7B8ZXKAXGC1669DYWB5
  • concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KMPTZSSWMHQ0YM018475YE4A

turso (54 failed):

  • addTenWorkflow | wrun_01KMPTNXGSXDSGT8V4KY1RM828
  • addTenWorkflow | wrun_01KMPTNXGSXDSGT8V4KY1RM828
  • wellKnownAgentWorkflow (.well-known/agent) | wrun_01KMPTQDTA4MTK696A11C9S86G
  • should work with react rendering in step
  • promiseAllWorkflow | wrun_01KMPTP5K20BCPY0X3D73SNAMP
  • promiseRaceWorkflow | wrun_01KMPTPA778D9A80E203J9FYEE
  • promiseAnyWorkflow | wrun_01KMPTPCPXZB6JN2ZA7FX7CKHZ
  • importedStepOnlyWorkflow | wrun_01KMPTQSX081VJMX0JCM1QVBZJ
  • hookWorkflow | wrun_01KMPTPVXNVFZ169DC8EK5304A
  • hookWorkflow is not resumable via public webhook endpoint | wrun_01KMPTQ7B8ZXKAXGC1669DYWB5
  • webhookWorkflow | wrun_01KMPTQGGT8GXZXB95K8E5TAE8
  • sleepingWorkflow | wrun_01KMPTQNYV33N38S706QRWX5H8
  • parallelSleepWorkflow | wrun_01KMPTR1WJECFM3AGMWWQS4RW2
  • nullByteWorkflow | wrun_01KMPTR59GTX0NPCND1ZAV9NJ5
  • workflowAndStepMetadataWorkflow | wrun_01KMPTR7NB4M37BH5Q0M0V0916
  • fetchWorkflow | wrun_01KMPTV3Z3NRHE7KPBZJ07GRDC
  • promiseRaceStressTestWorkflow | wrun_01KMPTV7GQY7TJTQ75DDRCVXCD
  • error handling error propagation workflow errors nested function calls preserve message and stack trace
  • error handling error propagation workflow errors cross-file imports preserve message and stack trace
  • error handling error propagation step errors basic step error preserves message and stack trace
  • error handling error propagation step errors cross-file step error preserves message and function names in stack
  • error handling retry behavior regular Error retries until success
  • error handling retry behavior FatalError fails immediately without retries
  • error handling retry behavior RetryableError respects custom retryAfter delay
  • error handling retry behavior maxRetries=0 disables retries
  • error handling catchability FatalError can be caught and detected with FatalError.is()
  • error handling not registered WorkflowNotRegisteredError fails the run when workflow does not exist
  • error handling not registered StepNotRegisteredError fails the step but workflow can catch it
  • error handling not registered StepNotRegisteredError fails the run when not caught in workflow
  • hookCleanupTestWorkflow - hook token reuse after workflow completion | wrun_01KMPTZ5R7AFC4M79G4HEAXCT6
  • concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KMPTZSSWMHQ0YM018475YE4A
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running | wrun_01KMPV0J4VSRVKXX57XWKBR1GR
  • stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars) | wrun_01KMPV16ATD728YT4M8WYQA06W
  • stepFunctionWithClosureWorkflow - step function with closure variables passed as argument | wrun_01KMPV1FJDB5R9PNGFPX0G8325
  • closureVariableWorkflow - nested step functions with closure variables | wrun_01KMPV1PE9QHE2YRNV4FQ5FVM9
  • spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step | wrun_01KMPV1RR9EZEDZ27V16YNGWSJ
  • health check (queue-based) - workflow and step endpoints respond to health check messages
  • pathsAliasWorkflow - TypeScript path aliases resolve correctly | wrun_01KMPV28FVGDYNJ82T1RBMSPV2
  • Calculator.calculate - static workflow method using static step methods from another class | wrun_01KMPV2FBXA0Y45KK2R6VH2JA9
  • AllInOneService.processNumber - static workflow method using sibling static step methods | wrun_01KMPV2N3BCBF51K6XKJA3XKN5
  • ChainableService.processWithThis - static step methods using this to reference the class | wrun_01KMPV2VYM8YN96W4F0QEK45P8
  • thisSerializationWorkflow - step function invoked with .call() and .apply() | wrun_01KMPV342JTEECR81NVBFQNFX9
  • customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE | wrun_01KMPV3CXDE12CF40C39043S7M
  • instanceMethodStepWorkflow - instance methods with "use step" directive | wrun_01KMPV3KWH7VKN1HY1PXAXCSQ8
  • crossContextSerdeWorkflow - classes defined in step code are deserializable in workflow context | wrun_01KMPV3Z8Q25CRZ7Y7SBQ6KZ6P
  • stepFunctionAsStartArgWorkflow - step function reference passed as start() argument | wrun_01KMPV47FGGX6PPX80GS5QT5TT
  • cancelRun - cancelling a running workflow | wrun_01KMPV4EE3RT19MPFCJ9K6EB8V
  • cancelRun via CLI - cancelling a running workflow | wrun_01KMPV4QTQJSJM1MN4T62HVG6K
  • pages router addTenWorkflow via pages router
  • pages router promiseAllWorkflow via pages router
  • pages router sleepingWorkflow via pages router
  • hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep | wrun_01KMPV5430EH2PBP4XGSQJC0J7
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_01KMPV5RT23WCYHPC5S5KJ4KVF
  • sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) | wrun_01KMPV64P6ZJGXETE7YK94ZPKD

Details by Category

✅ ▲ Vercel Production
App Passed Failed Skipped
✅ astro 76 0 7
✅ example 76 0 7
✅ express 76 0 7
✅ fastify 76 0 7
✅ hono 76 0 7
✅ nextjs-turbopack 81 0 2
✅ nextjs-webpack 81 0 2
✅ nitro 76 0 7
✅ nuxt 76 0 7
✅ sveltekit 76 0 7
✅ vite 76 0 7
✅ 💻 Local Development
App Passed Failed Skipped
✅ astro-stable 69 0 14
✅ express-stable 69 0 14
✅ fastify-stable 69 0 14
✅ hono-stable 69 0 14
✅ nextjs-turbopack-canary 58 0 25
✅ nextjs-turbopack-stable 75 0 8
✅ nextjs-webpack-canary 58 0 25
✅ nextjs-webpack-stable 75 0 8
✅ nitro-stable 69 0 14
✅ nuxt-stable 69 0 14
✅ sveltekit-stable 69 0 14
✅ vite-stable 69 0 14
✅ 📦 Local Production
App Passed Failed Skipped
✅ astro-stable 69 0 14
✅ express-stable 69 0 14
✅ fastify-stable 69 0 14
✅ hono-stable 69 0 14
✅ nextjs-turbopack-canary 58 0 25
✅ nextjs-turbopack-stable 75 0 8
✅ nextjs-webpack-canary 58 0 25
✅ nextjs-webpack-stable 75 0 8
✅ nitro-stable 69 0 14
✅ nuxt-stable 69 0 14
✅ sveltekit-stable 69 0 14
✅ vite-stable 69 0 14
✅ 🐘 Local Postgres
App Passed Failed Skipped
✅ astro-stable 69 0 14
✅ express-stable 69 0 14
✅ fastify-stable 69 0 14
✅ hono-stable 69 0 14
✅ nextjs-turbopack-canary 58 0 25
✅ nextjs-turbopack-stable 75 0 8
✅ nextjs-webpack-canary 58 0 25
✅ nextjs-webpack-stable 75 0 8
✅ nitro-stable 69 0 14
✅ nuxt-stable 69 0 14
✅ sveltekit-stable 69 0 14
✅ vite-stable 69 0 14
✅ 🪟 Windows
App Passed Failed Skipped
✅ nextjs-turbopack 75 0 8
❌ 🌍 Community Worlds
App Passed Failed Skipped
✅ mongodb-dev 5 0 0
❌ mongodb 56 2 8
✅ redis-dev 5 0 0
❌ redis 56 2 8
✅ turso-dev 5 0 0
❌ turso 4 54 8
✅ 📋 Other
App Passed Failed Skipped
✅ e2e-local-dev-nest-stable 69 0 14
✅ e2e-local-postgres-nest-stable 69 0 14
✅ e2e-local-prod-nest-stable 69 0 14

📋 View full workflow run

@VaguelySerious @claude
[ai] Fix WorkflowChatTransport blocking browser paint during stream r…
a96c546 
…econnect

Add macrotask yield (setTimeout(0)) in iteratorToStream's pull() method
so the browser can paint between chunks when replaying buffered data on
reconnect, instead of starving the main thread until the stream ends.

Closes #1465

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Peter Wielander <mittgfu@gmail.com>
@VaguelySerious @claude
Guard macrotask yield to browser-only environments
0a58e81 
The setTimeout(0) yield in iteratorToStream now only runs when
typeof window !== 'undefined', avoiding unnecessary per-chunk
latency on server-side consumers where there is no paint to unblock.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Peter Wielander <mittgfu@gmail.com>
@VaguelySerious VaguelySerious merged commit a0a7195 into main Mar 30, 2026
104 of 105 checks passed
@VaguelySerious VaguelySerious deleted the peter/issue-1465 branch March 30, 2026 17:44
@ghost ghost mentioned this pull request Mar 30, 2026
Merged
@shtefcs shtefcs mentioned this pull request May 12, 2026
Open
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@karthikscale3 karthikscale3 karthikscale3 approved these changes

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WorkflowChatTransport blocks browser paint during stream reconnect/resume

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@VaguelySerious @karthikscale3