Error message less-than-optimal when instrumentation cannot be loaded #78457
Description
Link to the code that reproduces this issue
https://codesandbox.io/p/devbox/pensive-feynman-lfsfss?file=%2Finstrumentation.ts
To Reproduce
- Start the application (npm run dev)
- Watch the console output.
Current vs. Expected behavior
Console output says:
$ next dev
▲ Next.js 15.4.0-canary.5
- Local: http://localhost:3000
- Network: http://172.17.0.2:3000
✓ Starting...
✓ Compiled /instrumentation in 573ms (22 modules)
[TypeError: Cannot set property message of [object Object] which has only a getter]
It is correct behaviour that an error occurs since the file instrumentation.ts results in an error when loaded.
Problem is that the actual error (in our case a zod error that occurs when the environment is parsed) is discarded, and a TypeError with no hint towards the actual error is thrown instead.
Reason is line 479 in next-dev-server.js:
async loadInstrumentationModule() {
let instrumentationModule;
if (this.actualInstrumentationHookFile && await this.ensurePage({
page: this.actualInstrumentationHookFile,
clientOnly: false,
definition: undefined
}).then(()=>true).catch(()=>false)) {
try {
instrumentationModule = await require((0, _path.join)(this.distDir, 'server', _constants.INSTRUMENTATION_HOOK_FILENAME));
} catch (err) {
// Here is the error:
err.message = `An error occurred while loading instrumentation hook: ${err.message}`;
throw err;
}
}
This line assumes hat the message property of the received error is writable, which may not be the case.
Provide environment information
Operating System:
Platform: win32
Arch: x64
Version: Windows 11 Pro
Available memory (MB): 28381
Available CPU cores: 16
Binaries:
Node: 22.10.0
npm: 10.9.0
Yarn: N/A
pnpm: N/A
Relevant Packages:
next: 15.3.0 // There is a newer version (15.3.1) available, upgrade recommended!
eslint-config-next: 15.3.0
react: 19.1.0
react-dom: 19.1.0
typescript: 5.8.3
Next.js Config:
output: standalone
⚠ There is a newer version (15.3.1) available, upgrade recommended!
Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue.
Read more - https://nextjs.org/docs/messages/opening-an-issueWhich area(s) are affected? (Select all that apply)
Instrumentation, Runtime
Which stage(s) are affected? (Select all that apply)
next dev (local)
Additional context
No response