Unhelpful error message output

[abea]

Describe the bug

Running npx @redocly/cli build-docs on an openapi JSON file, I receive TypeError: u?.match is not a function. No stack trace. Presumably somewhere the CLI expects a string and isn't getting one, but I have no idea where to look to fix that.

I previously got the error Error: Invalid reference token: FundingCode. Again, no stack trace. That I could at least figure out eventually when I realized there wasn't a schema for FundingCode in the JSON, but this u?.match() isn't giving me anything to work with.

To Reproduce

Really no idea. I can't provide my full API spec and don't know how to narrow it down to reproduce. I attempted to reduce my set of paths to find the problem, but that was inconclusive. At the moment the issue is not having enough error information to go on.

Expected behavior

Logs

Prerendering docs
TypeError: u?.match is not a function

OpenAPI description

Redocly version(s)

2.47.0

Node.js version(s)

24.19.0

OS, environment

Alpine linux

Additional context

[AlbinaBlazhko17]

Thanks for the report, @abea. The build-docs command currently drops the stack trace so you can't see where. We'll fix the missing stack trace.
To find the problem now, run:
npx @redocly/cli lint your-api.json --extends=spec
That reports only specification errors, so the output stays short. I assume that the issue is in non-string refs.
One note: if your redocly.yaml sets struct or no-unresolved-refs to off in its rules section, that setting still applies and hides the error - check it first.