fix(mongodb): prevent webhook response stream close race

[dustintownsend]

Summary

• fix a race in MongoDB streamer readFromStream() where a close signal could arrive during initial load and close the reader before buffered chunks were delivered
• defer close until initial-load buffered chunks are flushed
• guard against duplicate/late close handling with explicit closed state
• add a regression test that repeatedly exercises read-before-write with immediate close (the webhook response pattern)

Why

The MongoDB E2E webhookWorkflow failure (expected '' to be 'Hello from webhook!') is consistent with a dropped stream chunk when close and first chunk occur back-to-back.

Validation

• pnpm --filter @workflow-worlds/mongodb test:only
  • result: 55 passed, 0 failed

[github-actions]

Benchmark Comparison

Cross-comparison of workflow performance across World implementations.

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

workflow with no steps

World	Workflow Time	Wall Time	Overhead	vs Fastest
🥇 💾 Starter (in-memory)	0.008s (-43.4% 🟢)	1.006s (~)	0.997s	1.00x
🔴 Redis	0.020s (~)	1.010s (~)	0.990s	2.51x
💻 Local	0.028s (+0.7%)	1.007s (~)	0.979s	3.40x
🍃 MongoDB	0.049s (+5.0%)	1.010s (~)	0.961s	5.99x
🗄️ Turso	0.092s (+152.5% 🔺)	1.010s (~)	0.917s	11.41x

workflow with 1 step

World	Workflow Time	Wall Time	Overhead	vs Fastest
🥇 💾 Starter (in-memory)	0.023s (-44.0% 🟢)	1.004s (~)	0.980s	1.00x
🔴 Redis	0.057s (+2.9%)	1.007s (~)	0.949s	2.44x
💻 Local	0.080s (-17.3% 🟢)	1.006s (~)	0.925s	3.43x
🍃 MongoDB	0.253s (-8.5% 🟢)	1.009s (~)	0.756s	10.82x
🗄️ Turso	0.294s (+21.4% 🔺)	1.008s (-1.4%)	0.714s	12.57x

workflow with 10 sequential steps

World	Workflow Time	Wall Time	Overhead	vs Fastest
🥇 💾 Starter (in-memory)	0.199s (-40.6% 🟢)	1.003s (~)	0.804s	1.00x
🔴 Redis	0.422s (~)	1.006s (~)	0.584s	2.12x
💻 Local	0.640s (-1.4%)	1.005s (~)	0.365s	3.21x
🍃 MongoDB	2.102s (-1.4%)	3.011s (~)	0.909s	10.55x
🗄️ Turso	2.111s (~)	3.008s (~)	0.897s	10.60x

workflow with 10 parallel steps

World	Workflow Time	Wall Time	Overhead	vs Fastest
🥇 💾 Starter (in-memory)	0.094s (-27.3% 🟢)	1.004s (~)	0.910s	1.00x
🔴 Redis	0.162s (-0.6%)	1.006s (~)	0.844s	1.71x
💻 Local	0.273s (-1.5%)	1.006s (~)	0.732s	2.89x
🗄️ Turso	1.525s (-3.2%)	2.008s (~)	0.483s	16.16x
🍃 MongoDB	1.570s (~)	2.009s (~)	0.439s	16.63x

---

Stream Benchmarks

Stream benchmarks include Time to First Byte (TTFB) metrics.

workflow with stream

World	Workflow Time	TTFB	Wall Time	Overhead	vs Fastest
🥇 💾 Starter (in-memory)	0.037s (-47.3% 🟢)	1.003s (~)	1.005s (~)	0.968s	1.00x
🔴 Redis	0.090s (~)	1.002s (~)	1.007s (~)	0.917s	2.40x
💻 Local	0.137s (-1.9%)	0.992s (~)	1.008s (~)	0.871s	3.65x
🗄️ Turso	0.472s (+6.0% 🔺)	0.960s (-2.6%)	1.008s (~)	0.537s	12.58x
🍃 MongoDB	0.480s (-3.2%)	0.951s (+1.7%)	1.009s (~)	0.528s	12.81x

---

Summary: Average Performance by World

World	Avg Workflow Time	Benchmarks
💾 Starter (in-memory)	0.073s	5
🔴 Redis	0.150s	5
💻 Local	0.232s	5
🍃 MongoDB	0.891s	5
🗄️ Turso	0.899s	5

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)
• Wall Time: Total testbench time (trigger workflow + poll for result)
• Overhead: Testbench overhead (Wall Time - Workflow Time)
• vs Fastest: How much slower compared to the fastest World for this benchmark

Worlds:

• 💻 Local: Built-in workflow world
• 🐘 Postgres: PostgreSQL database world
• ▲ Vercel: Vercel production world
• 💾 Starter: In-memory reference implementation
• 🍃 MongoDB: MongoDB database world
• 🔴 Redis: Redis/BullMQ backend

[github-actions]

❌ E2E Test Results

World	Passed	Failed	Skipped	Total
Turso	26	19	3	48	❌
MongoDB	45	0	3	48	✅
Redis	45	0	3	48	✅
Total	116	19	9	144

Failed Tests

Turso — 19 failed

• e2e concurrent hook token conflict - two workflows cannot use the same hook token simultaneously

  LibsqlError: SQLITE_BUSY: database is locked

• e2e stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)

  Error: STACK_TRACE_ERROR

• e2e stepFunctionWithClosureWorkflow - step function with closure variables passed as argument

  Error: STACK_TRACE_ERROR

• e2e closureVariableWorkflow - nested step functions with closure variables

  Error: STACK_TRACE_ERROR

• e2e spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step

  Error: STACK_TRACE_ERROR

• e2e health check (queue-based) - workflow and step endpoints respond to health check messages

  AssertionError: expected false to be true // Object.is equality

• e2e health check (CLI) - workflow health command reports healthy endpoints

  AssertionError: expected false to be true // Object.is equality

• e2e pathsAliasWorkflow - TypeScript path aliases resolve correctly

  Error: STACK_TRACE_ERROR

• e2e Calculator.calculate - static workflow method using static step methods from another class

  Error: STACK_TRACE_ERROR

• e2e AllInOneService.processNumber - static workflow method using sibling static step methods

  Error: STACK_TRACE_ERROR

• e2e ChainableService.processWithThis - static step methods using this to reference the class

  Error: STACK_TRACE_ERROR

• e2e thisSerializationWorkflow - step function invoked with .call() and .apply()

  Error: STACK_TRACE_ERROR

• e2e customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE

  Error: STACK_TRACE_ERROR

• e2e instanceMethodStepWorkflow - instance methods with "use step" directive

  Error: STACK_TRACE_ERROR

• e2e crossContextSerdeWorkflow - classes defined in step code are deserializable in workflow context

  Error: STACK_TRACE_ERROR

• e2e stepFunctionAsStartArgWorkflow - step function reference passed as start() argument

  Error: STACK_TRACE_ERROR

• e2e pages router addTenWorkflow via pages router

  Error: Failed to trigger workflow: http://localhost:3000/api/trigger-pages?workflowFile=workflows%2F99_e2e.ts&workflowFn

• e2e pages router promiseAllWorkflow via pages router

  Error: Failed to trigger workflow: http://localhost:3000/api/trigger-pages?workflowFile=workflows%2F99_e2e.ts&workflowFn

• e2e pages router sleepingWorkflow via pages router

  Error: Failed to trigger workflow: http://localhost:3000/api/trigger-pages?workflowFile=workflows%2F99_e2e.ts&workflowFn

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