Ideally, this would use something similar to the linux minimal-bootstrap path to bootstrap fully from source without using the bootstrap-files mechanism, for reproducibility and auditability reasons. Is there any way to do that with Cygwin?

I'm sure it's possible, but I think it's premature when the only stdenv currently doing it is x86 linux. I suspect we'd want to refactor and share a lot of linux/minimal-bootstrap. I don't think cygwin is the platform we want to use to build that abstraction. Darwin or freebsd would probably be better.

Ideally, this would use something similar to the linux minimal-bootstrap path to bootstrap fully from source without using the bootstrap-files mechanism, for reproducibility and auditability reasons. Is there any way to do that with Cygwin?

I'm sure it's possible, but I think it's premature when the only stdenv currently doing it is x86 linux. I suspect we'd want to refactor and share a lot of linux/minimal-bootstrap. I don't think cygwin is the platform we want to use to build that abstraction. Darwin or freebsd would probably be better.

Very fair, then feel free to discard my comments. The work here looks good!

I've marked this ready because all the original dependencies are merged, and I think the change is still good.

Unfortunately it doesn't build at the moment due to regressions, which I'll fix and link in the top comment.

Can we just cross compile from a pure bootstrap platform and say, well, you need multiple types of builders if it isn't cached?

I don't see why not.

Can we just cross compile from a pure bootstrap platform and say, well, you need multiple types of builders if it isn't cached?

I did have a stdenv based on stdenv/cross before this one. It would be very frustrating for an end user IMO.

This is quite similar to what freebsd and darwin do. This change doesn't even have the stdenv yet. I really just want all the things required by stdenv to be in hydra, so we can keep them building while we do the rest of the work.

I think long-term, minimal-bootstrap would be a great way to go, but it's very linux-centric at the moment.

#123095 (comment) to be clear, something like this is what I am thinking.

We can make a "make bootstrap tools" of sorts, but rather than using it to produce something we fetch in a separate eval, we would just directly use it in the native bootstrap. We'd rely on regular substitution rather than fetching a fixed output.

#123095 (comment) to be clear, something like this is what I am thinking.

Like with minimal-bootstrap, I'm not against this idea, but I'd rather start off with a conventional stdenv (like darwin/freebsd) until the concept has been proven.