nix profile subcommands rely on index identifier #7961
Description
The main identifier for package entries in Nix profiles is the index. The index is quite bad as an identifier. Consider the following scenario:
$ nix profile list
....
3 flake:nixpkgs#legacyPackages.x86_64-linux.vim github:NixOS/nixpkgs/9952d6bc395f5841262b006fbace8dd7e143b634#legacyPackages.x86_64-linux.vim /nix/store/9hcby08vmd6k3zl3clwvlw5y5vkmc3z6-vim-9.0.0609
4 flake:nixpkgs#legacyPackages.x86_64-linux.cowsay github:NixOS/nixpkgs/9952d6bc395f5841262b006fbace8dd7e143b634#legacyPackages.x86_64-linux.cowsay /nix/store/azn0g0m6yg6m9vmdp3wq6wjbsd1znv44-cowsay-3.7.0 /nix/store/qgsl9bd6vvnpjaxhdnzg0xmycg3652c0-cowsay-3.7.0-man
5 flake:nixpkgs#legacyPackages.x86_64-linux.nano github:NixOS/nixpkgs/9952d6bc395f5841262b006fbace8dd7e143b634#legacyPackages.x86_64-linux.nano /nix/store/hhr8ijr2p5qf3lyklzyw8cndhsmpklsv-nano-7.2
$ nix profile remove 3
removing 'flake:nixpkgs#legacyPackages.x86_64-linux.vim'
$ nix profile remove 4
removing 'flake:nixpkgs#legacyPackages.x86_64-linux.nano'In this case the numeric identifier in nix profile shifts with every change of the profile. In this case the user intended to remove vim and cowsay, but instead removed vim and nano. Very confusing.
The identifier in nix profile should be stable. It is probably up for debate what that should be.