In fact, reproducing artifacts will have more uncertain factors without a correctly designed tool chain. Accidentally introducing timestamps is just one common case, others include the order of multi-threaded builds, Haskell's GHC compiler has had this problem for a long time, and sometimes Rust seems to be affected as well. There are also some tricky situations, which are related to the features of the file system.
It is misleading to say that NixOS has complete reproducibility. However, NixOS is indeed more advanced in some aspects. You can reproduce a working development environment, you can easily test the build process you will deploy to CI locally, move your favorite configurations between computers, or share certain parts between them. This is the benefits of declarative package management (or package build system).
Unreproducible situations do occur during the building process of packages (derivation), but these situations usually have nothing to do with functionality, and it is easy to see where the problem is with diffscope. We have specifically tracked and dealt with these issues. At present, they are still within a relatively controllable range.
I would also thank @anthk for introducing people to Guix. As a late sibling to Nix (the ecosystem), Guix is cleaner in handling the basic toolchain and does a better job in full source bootstrapping, which we are working hard to learn and improve. However, Guix and Nix have the same constraints, they can only reproduce the way the system is built and composed, not the artifact itself. We both track reproducibility problems, and there are interested maintainers actively addressing these issues.
When it comes to whether you should choose NixOS (or Guix), I think you should weigh your workflow, usage habits, and learning costs. Given the significant difference in the way of thinking, we can't make it painless for people to migrate from distributions like Debian/Arch or Ubuntu to NixOS. But if you really need it, I believe you will still come one day
It is misleading to say that NixOS has complete reproducibility. However, NixOS is indeed more advanced in some aspects. You can reproduce a working development environment, you can easily test the build process you will deploy to CI locally, move your favorite configurations between computers, or share certain parts between them. This is the benefits of declarative package management (or package build system).
Unreproducible situations do occur during the building process of packages (derivation), but these situations usually have nothing to do with functionality, and it is easy to see where the problem is with diffscope. We have specifically tracked and dealt with these issues. At present, they are still within a relatively controllable range.
See
https://reproducible.nixos.org/
https://github.com/NixOS/nixpkgs/issues?q=sort%3Aupdated-des...
I would also thank @anthk for introducing people to Guix. As a late sibling to Nix (the ecosystem), Guix is cleaner in handling the basic toolchain and does a better job in full source bootstrapping, which we are working hard to learn and improve. However, Guix and Nix have the same constraints, they can only reproduce the way the system is built and composed, not the artifact itself. We both track reproducibility problems, and there are interested maintainers actively addressing these issues.
See
https://issues.guix.gnu.org/search?query=reproducible
When it comes to whether you should choose NixOS (or Guix), I think you should weigh your workflow, usage habits, and learning costs. Given the significant difference in the way of thinking, we can't make it painless for people to migrate from distributions like Debian/Arch or Ubuntu to NixOS. But if you really need it, I believe you will still come one day