[BUG]: Next plugin not loaded

[ganlhi]

Tracer Version(s)

5.42.0

Node.js Version(s)

22.14.0

Bug Report

I'm initialising dd-trace from the instrumentaion.ts file of my NextJS app. I noticed nothing happened within the next plugin. For instance the following code didn't log anything:

    tracer.use('next', {
      service: 'my-app',
      hooks: {
        request: (span, request, response) => {
          console.log({ span, request, response });
        },
      },
    });

So I tried to understand what was happening, and I added a log in node_modules/dd-trace/packages/dd-trace/src/plugin_manager.js:

  loadPlugin (name) {
    const Plugin = pluginClasses[name]
    console.log("LOADPLUGIN", name, Plugin);

This log indicates classes for other plugins, but not for the next plugin:

LOADPLUGIN dns [class DNSPlugin extends CompositePlugin]
LOADPLUGIN net [class NetPlugin extends Plugin]
LOADPLUGIN next undefined

I don't know why, but the result is that the plugin's hook is never called.

Reproduction Code

In instrumentation.ts of a NextJS 15.2.1 app:

import trace from 'dd-trace';

export async function register() {
  if (process.env.NEXT_RUNTIME === 'nodejs') {
    const tracer = trace.init({
      logInjection: true,
      startupLogs: true,
      hostname: process.env.STATSD_HOST,
      port: process.env.STATSD_PORT,
      runtimeMetrics: true,
      env: 'staging',
    });

    tracer.use('next', {
      service: 'my-app',
      hooks: {
        request: (span, request, response) => {
          console.log({ span, request, response });
        },
      },
    });
  }
}

Error Logs

No response

Tracer Config

{
  logInjection: true,
  startupLogs: true,
  hostname: process.env.STATSD_HOST,
  port: process.env.STATSD_PORT,
  runtimeMetrics: true,
  env: 'staging',
}

Operating System

Darwin Kernel Version 24.3.0

Bundling

Next.js