I'm not sure there, I see what you mean now. Thanks for the clarification. I'm not familiar with that case, maybe someone else here on HN would know. Usually most people just don't have to worry about that when contributing to open source. Also depending on the software license, it might trump the supposed claimed copyright of your employer, e.g. GPL code once GPL'd there's no going around it. Or other licenses which revoke your use of their code the second you try to sue. Software licenses are kind of smart in their own regard.
Sidenote: I personally would refuse to work for anybody who tries to own code I write outside of work with my own hardware / tools. Thankfully where I work we're very open source friendly, not only do we use open source tooling / OS' but in some cases we contribute back directly where appropriate.
Every place that I’ve worked at with a clause like that in the contract doesn’t get to employ me until it’s removed. Usually they can’t understand my objections, and has just been put in there by their lawyers, but it’s always come out eventually.
Sidenote: I personally would refuse to work for anybody who tries to own code I write outside of work with my own hardware / tools. Thankfully where I work we're very open source friendly, not only do we use open source tooling / OS' but in some cases we contribute back directly where appropriate.