multiStreamAppend fails with "dd-trace": "^5.87.0" and "@kurrent/kurrentdb-client": "^1.1.2"

[Kunamatata]

🐛 Current behavior

We use dd-trace package which also uses the grpc package as a dependency as well as the kurrent package which also uses the grpc package. It seems like dd-trace does sometimes mess with other libs that use grpc and we are seeing this when we turn dd-tracing on.

We really need tracing when we fully release to all customers in prod and trying to figure out what is interfering.

2026-04-24T17:31:25.693Z server �[31merror�[39m:      {
2026-04-24T17:31:25.693Z server �[31merror�[39m:        meta: {
2026-04-24T17:31:25.693Z server �[31merror�[39m:          error: {
2026-04-24T17:31:25.693Z server �[31merror�[39m:            name: �[32m'TypeError'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            message: �[32m"Cannot read properties of undefined (reading 'on')"�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            stack: �[32m"TypeError: Cannot read properties of undefined (reading 'on')\n"�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at <anonymous> (/Users/maxime/work/backend/node_modules/.pnpm/@kurrent+kurrentdb-client@1.1.2/node_modules/@kurrent/kurrentdb-client/src/streams/appendToStream/multiStreamAppend.ts:68:14)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at new Promise (<anonymous>)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at <anonymous> (/Users/maxime/work/backend/node_modules/.pnpm/@kurrent+kurrentdb-client@1.1.2/node_modules/@kurrent/kurrentdb-client/src/streams/appendToStream/multiStreamAppend.ts:43:7)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at Client.execute (/Users/maxime/work/backend/node_modules/.pnpm/@kurrent+kurrentdb-client@1.1.2/node_modules/@kurrent/kurrentdb-client/src/Client/index.ts:474:20)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at async Object.save (/Users/maxime/work/backend/apps/work-management/server/src/infrastructure/repository.ts:101:27)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at async <anonymous> (/Users/maxime/work/backend/apps/work-management/server/src/service/task-service.ts:148:36)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at async taskCreateFromPhoneChannel (/Users/maxime/work/backend/apps/work-management/server/src/graphql/task/task-mutations.ts:57:36)\n'�[39m +
2026-04-24T17:31:25.693Z server �[31merror�[39m:              �[32m'    at async <anonymous> (/Users/maxime/work/backend/libs/graphql/src/graphql/graphql-express-router.ts:78:9)'�[39m
2026-04-24T17:31:25.693Z server �[31merror�[39m:          },
2026-04-24T17:31:25.693Z server �[31merror�[39m:          dd: {
2026-04-24T17:31:25.693Z server �[31merror�[39m:            trace_id: �[32m'b28c44e134929f15086aba814b36a630'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            span_id: �[32m'3976701658965909850'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            service: �[32m'backend'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            version: �[32m'0.0.16'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:            env: �[32m'local'�[39m
2026-04-24T17:31:25.693Z server �[31merror�[39m:          }
2026-04-24T17:31:25.693Z server �[31merror�[39m:        },
2026-04-24T17:31:25.693Z server �[31merror�[39m:        dd: {
2026-04-24T17:31:25.693Z server �[31merror�[39m:          trace_id: �[32m'b28c44e134929f15086aba814b36a630'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          span_id: �[32m'3976701658965909850'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          service: �[32m'backend'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          version: �[32m'0.0.16'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          env: �[32m'local'�[39m
2026-04-24T17:31:25.693Z server �[31merror�[39m:        },
2026-04-24T17:31:25.693Z server �[31merror�[39m:        context: {
2026-04-24T17:31:25.693Z server �[31merror�[39m:          userId: �[1mnull�[22m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          correlationId: �[32m'2205e12b-b2e5-40f6-929e-0497778cc127'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          impersonatingUserId: �[90mundefined�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          application: �[32m'workmanagement-server'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          orgId: �[32m'ORGjowips9'�[39m,
2026-04-24T17:31:25.693Z server �[31merror�[39m:          phoneChannelId: �[32m'PNsLC8GsIR'�[39m
2026-04-24T17:31:25.693Z server �[31merror�[39m:        }
2026-04-24T17:31:25.693Z server �[31merror�[39m:      }```

### 🔍 Steps to reproduce

1. Enable dd-trace which is called via the `init()` function inside the pacakge (`DD_TRACE_ENABLED`)
2. Attempt a multiStreamAppend call

### Reproducible link

N/A

### 💭 Expected behavior

1. DD_TRACE_ENABLED: true and multiStreamAppend does not fail

### Package version

1.1.2

### KurrentDB Version

latest cloud instance

### Connection string

N/A

### ☁️ Deployment Environment

Multi-node cluster (Cloud)

### Other Deployment Details

_No response_

### Operating system

_No response_

[linear]

DEV-1593

[w1am]

Hi Maxime,

Thanks for the detailed report. I reproduced it end to end, and the root cause is in dd-trace-js's automatic @grpc/grpc-js instrumentation rather than in @kurrent/kurrentdb-client, which is why it only shows up when DD_TRACE_ENABLED=true. Under the hood, dd-trace doesn't handle streaming grpc calls cleanly under certain shapes, so the call silently returns undefined instead of a stream, which is what cascades into the TypeError you saw. Same call works fine with dd-trace disabled.

I filed an upstream issue with Datadog along with a minimal repro, and I'll update this thread as soon as they ship a fix.

[Kunamatata]

@w1am wonderful thank you so much!

[Kunamatata]

@w1am @alexeyzimarev Any updates from dd-trace upstream fix?

[w1am]

I followed up today, and their customer support mentioned the engineering team is still investigating and they’ll share findings as soon as possible.