In Nixpkgs we have on several places autogenerated data. This issue is a placeholder for discussions on autogenerated data in Nixpkgs.

• Python: Python: autogenerate PyPI source data (2) #15007 , @FRidh
• Ruby: Python: autogenerate PyPI source data (2) #15007 (comment) , @zimbatm
• ELPA/MELPA , @ttuegel
• KDE Generate Hackage/LTS nix expressions on the fly rather than have them in the repo #16130 (comment) , @ttuegel
• Haskell (Generate Hackage/LTS nix expressions on the fly rather than have them in the repo #16130)
• Node
• Go
• Xorg
• luarocks packages

Discussion on importing from derivation and how Hydra handles it: NixOS/nix#954