> You could clone an open source repo and use that if you're worried. The value isn't the code; it's the conversation.
Open Source code plagiarism is a major problem and doing random forks/clone of popular repos to up your github cred is a thing and in my opinion it is unethical. Even if the interviewee tells you it is an open source project you will have a hard time distinguishing their code and the code from the original repo.
I think the interviewer should show their own production code and ask the interviewee what they think and what suggestion they have to offer. If you are not comfortable showing your own production code ask the interviewee to explore an open source codebase.
The "Show me what you got" approach puts way too much unjust pressure on a candidate and might force them to chose unethical means just to impress you. Then again if you want be impressed and if it is working so far for you, ignore my whole argument.
Who said th ex interviewee must present 'own' code there?
The conversation can just as well be around a library, product or system that isn't authored or contributed to, by the interviewee.
'What architecture is used here, and what are the down and upsides in this implementation'. 'What would you do different'. 'Which part do you admire, and what don't you like'. Etc.
Also why would I voluntarily talk about codebases authored by anyone other than me while having in-depth knowledge about it? Nobody looks under the hood of things that interests them, let alone be critical of it’s design.
Talking about product and system design is something that is vastly different than stand-alone codebase. If you as an interviewer are interested about something you have the capacity of directing the conversation flow toward that. Ask them introductory questions about a product/system, gauge their interest in it then ask their opinion about it.
> Nobody looks under the hood of things that interests them, let alone be critical of it’s design.
Do you honestly believe this?
Many people do this. I do this. It's the best way to learn¹. There are repeating Ask-HN threads requesting for "high quality Open Source Software to learn from" for example.
¹Edit: on second thought: probably not the "best" way. Not for me, anyway. Just a good way.
You could clone an open source repo and use that if you're worried. The value isn't the code; it's the conversation.
"Bring your own code" is just meant to put the interviewee at ease because they are already prepared to talk about their own code.