Server crash in Next.js with invalid api route URI and dd-trace

[jakst]

Describe the bug

The crash happens under the following circumstances:

• There is a Next.js catch all page route, like pages/[...catchAll].js
• The Next.js server is started with dd-trace running, like this NODE_OPTIONS='--require ./datadog' next start and datadog.js has this content: require('dd-trace').init(). This applies to any version of dd-trace between 1.2.0 and the latest 2.3.1.
• There is a request to an api route with an invalid URI /api/%ff.

It produces the following stack trace from Next.js

./node_modules/next/dist/shared/lib/router/utils/route-matcher.js:18
                throw new _utils.DecodeError('failed to decode param');
                      ^
DecodeError: failed to decode param
    at decode (./node_modules/next/dist/shared/lib/router/utils/route-matcher.js:18:23)
    at ./node_modules/next/dist/shared/lib/router/utils/route-matcher.js:26:80
    at Array.map (<anonymous>)
    at ./node_modules/next/dist/shared/lib/router/utils/route-matcher.js:26:67
    at Array.forEach (<anonymous>)
    at Object.match (./node_modules/next/dist/shared/lib/router/utils/route-matcher.js:22:29)
    at NextNodeServer.handleApiRequest (./node_modules/next/dist/server/base-server.js:538:39)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
error Command failed with exit code 1.

I don't know whether the actual error is in next.js or in dd-trace, but they are both black boxes to me and I only get a stack trace containing next.js code. I have cross posted this in the Next.js repo: vercel/next.js#35132

Environment

• Operation system: MacOS v12.2.1
• Node version: v16.14
• Tracer version: v1.2.0 up to v2.3.1
• Agent version: Not relevant

To reproduce

• Clone this repo: https://github.com/jakst/nextjs-router-crash-reproduction
• Run yarn build
• Run yarn start
• Visit http://localhost:3000/api/%ff