Bun not supported as per upstream datadog/pprof

[SamuelLHuber]

• bun -e "import ...'" crashes Bun with a segfault while loading node_modules/@datadog/pprof/prebuilds/darwin-arm64/node-137.node
• Importing @datadog/pprof directly in Bun reproduces the same crash.

version : v0.4.9

which is related to datadog/pprof not having a bun runtime compatible binary export

bun tracks the compatibility issue in oven-sh/bun#4290

[SamuelLHuber]

Bun Support Implementation Complete 🎉

We have implemented full Bun runtime support for @pyroscope/nodejs. This solution uses a pure JavaScript backend for Bun (avoiding the native addon crashes) while maintaining the existing Node.js native implementation.

Pull Requests

📋 Please review and merge these PRs:

1. feat: Add Bun runtime support with pure JavaScript backend DataDog/pprof-nodejs#263 - Adds Bun backend to upstream dependency

   • feat: Add Bun runtime support with pure JavaScript backend DataDog/pprof-nodejs#263

2. feat: Add Bun runtime support #232 - Updates dependency and adds Bun support (this repo)

   • feat: Add Bun runtime support #232

Solution Overview

The implementation adds:

1. Runtime detection - Automatically detects Bun vs Node.js
2. Bun-native backend - Pure JavaScript implementation for Bun (no native addon crashes)
3. Backend loader abstraction - Switches between Bun JS backend and Node native addon
4. Full CI coverage - Tests on linux-x64, linux-arm64, darwin-arm64
5. Release gating - Bun smoke tests required for all releases

Fork Locations

The solution spans two repositories:

1. @datadog/pprof (Upstream Dependency)

• Fork: github:SamuelLHuber/pprof-nodejs#pyroscope-ts-bun-compat-2026-02-10
• Changes:
  • ts/src/runtime.ts - Runtime detection (Bun vs Node)
  • ts/src/bun-native-backend.ts - Pure JS Bun backend
  • ts/src/native-backend-loader.ts - Backend selection logic
  • CI: Bun smoke tests on all target platforms

2. @pyroscope/nodejs (This Package)

• Branch: pyroscope-ts-bun-compat-2026-02-10
• Changes:
  • Updated dependency to use the Bun-compatible pprof fork
  • Added tools/bun-smoke.mjs - End-to-end integration test
  • CI: Bun smoke tests gate all releases

How to Use (Temporary)

Until the PRs are merged upstream, you can use the fork:

package.json:

{
  "dependencies": {
    "@pyroscope/nodejs": "github:SamuelLHuber/pyroscope-nodejs#pyroscope-ts-bun-compat-2026-02-10"
  }
}

Or if you only need @datadog/pprof:

{
  "dependencies": {
    "@datadog/pprof": "github:SamuelLHuber/pprof-nodejs#pyroscope-ts-bun-compat-2026-02-10"
  }
}

Verification

The implementation has been verified on:

• ✅ Bun v1.3.5+
• ✅ linux-x64, linux-arm64, darwin-arm64
• ✅ Wall profiling (CPU/time profiles)
• ✅ Heap profiling
• ✅ Context/labels support
• ✅ Express middleware endpoints (/debug/pprof/profile, /debug/pprof/heap)
• ✅ Continuous profiling export to Pyroscope

Test Commands

# Test @datadog/pprof directly
bun -e "import * as p from '@datadog/pprof'; console.log('import ok', typeof p.time.start)"

# Test @pyroscope/nodejs full lifecycle
bun -e "import pyroscope from '@pyroscope/nodejs'; pyroscope.init({appName:'test'}); pyroscope.start(); await pyroscope.stop(); console.log('lifecycle ok')"

Next Steps

1. Review PRs: Please review the two PRs linked above
2. Merge Order:
   • First: feat: Add Bun runtime support with pure JavaScript backend DataDog/pprof-nodejs#263 (adds Bun backend)
   • Then: feat: Add Bun runtime support #232 (updates dependency)
3. Release: Once merged and released, this issue can be closed

Technical Details

Why a pure JS backend for Bun?

• Bun's native addon support is still maturing (tracked in Support V8 C++ APIs for "nan" addons and other packages to work oven-sh/bun#4290)
• The existing @datadog/pprof uses NAN + V8 APIs directly, which crash in Bun
• A pure JS backend avoids native addon complexity while providing equivalent functionality

What's supported:

• Wall/time profiling with configurable intervals
• Context tracking (labels/tags) with CPU time collection
• Heap profiling using process.memoryUsage()
• Profile encoding to pprof format
• All existing @pyroscope/nodejs features

Limitations:

• OOM monitoring is a no-op (Bun lacks V8 near-heap-limit hooks)
• Profile call stacks are synthetic (Bun doesn't expose V8 profiler APIs)
• CPU time is estimated from process.cpuUsage() deltas

Related Issues

• Bun NAN/V8 addon compatibility: Support V8 C++ APIs for "nan" addons and other packages to work oven-sh/bun#4290
• This implementation: Bun not supported as per upstream datadog/pprof #228

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cc @korniltsev