Add a git worktree (or checkout) in ./nixpkgs:
git worktree add /path/to/by-name-migrate/nixpkgs
The script will create /tmp/by-name-migrate, and copy some files (about 10000 nix files) inside to test evaluation. Edit temp_path in script if you don't want this.
Run script:
nix develop
python migrate.py
It takes about 4 minutes. No multi-threading optimization here.
Stage and commit all files:
cd nixpkgs
git stage .
git commit -m "test"
Review (in nixpkgs root):
nixpkgs-review rev HEAD
nixpkgs-vet --base . .
Also you can run ofborg eval checks, see Running meta checks locally.
If anything goes wrong, remove:
git reset --hard HEAD~1