Reproduction for sentry-javascript#18572

[andreiborza]

Summary

Reproduction for getsentry/sentry-javascript#18572

OpenTelemetry context not propagating correctly when using @sentry/nestjs with custom OTel setup (skipOpenTelemetrySetup: true) and SentryContextManager. Traces randomly break into multiple partial traces under load, especially with gRPC endpoints.

Reproduction result

100% of spans are orphaned — zero correctly-parented spans. The SentryContextManager completely loses context propagation under concurrent gRPC traffic across multiple microservices.

Setup (matches reporter's production config)

• NestJS hybrid app (HTTP + two gRPC microservices on separate ports)
• Sentry + custom OTel SDK with SentryContextManager, SentryPropagator, SentrySpanProcessor
• skipOpenTelemetrySetup: true with manual OTel configuration
• Custom sampler using wrapSamplingDecision (health-check filter)
• connectMicroservice() with inheritAppConfig: false
• Double exporter registration (top-level traceExporter + inside BatchSpanProcessor)
• loader: { defaults: true } in gRPC options
• ContextDebugSpanProcessor that logs ORPHAN vs PARENTED spans (capped at 10 each)
• Test client with ramping concurrent waves hitting all endpoints

How to run

cd sentry-javascript/18572
npm install
npx nest build
node dist/instrument.js
# In another terminal:
node dist/test-client.js

Check server logs for [CONTEXT-DEBUG] lines — you'll see only ORPHAN entries and zero PARENTED entries.

Key findings

• The bug reproduces locally with this setup (reporter could not reproduce locally before)
• Every single span ends up orphaned — not just some, all of them
• The /test-cross-service endpoint (concurrent calls to both hero and villain gRPC services) is the most realistic trigger
• Context is already lost at span creation time, not just at end time

Notes

• Regression introduced between v10.25.0 and v10.27.0
• Suspected related to #18178 / PR #18239
• Disabling Sentry entirely fixes the issue; removing tracesSampleRate/SentrySpanProcessor does not