Trying to reproduce the release build of a popular Go software. There are Makefiles and it's pretty basic, but coming up with slight differences. Taking bets:
3/5 Filippo is stupid
3/10 Owner messed up
Three hours in. I know much more about embedded GOROOT paths.
Interestingly, the compiler will patch the paths of the symbols in the stdlib to match the GOROOT. That's smart, avoids recompiling the stdlib at every GOROOT change, but allows debuggers to find the stdlib files.
Also, should make reproducible builds just work.
So it's not this.
Figured it out! 🙌 And got it to reproduce 💥
The default GOROOT matters to the build ID because it's written to zversion.go, which is intentionally hashed in to detect toolchain changes.
Not, as I thought, because of the filepaths in the stdlib build IDs. The tree is recomputed with the current GOROOT instead. So every time you change GOROOT, the stdlib *is* rebuilt. (My previous tweet was wrong!)
All bets are off, it's Filippo is stupid.