Is using the `./.` directory in flakes still an antipattern?

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The linked page says it’s bad because the name given to the path in the nix store isn’t controlled, so the hash differs. This isn’t a problem in nix since it’s always named ...-source anyway. But using ./. is still likely to copy the directory an extra time into the nix store.

{
  outputs = { ... }: {
    foo = "${./.}";
  };
}

$ nix eval .#foo
"/nix/store/blrp8010cjvs8kv4jngvgj3fc6g5rvxc-dnpq4ndp6j41asnl6h5ylnl6hw7vyks3-source"

compared to:

{
  outputs = { self }: {
    foo = "${self}";
  };
}

$ nix eval .#foo
"/nix/store/xy6bd1cch2c36i8y3d4rqa1kqw4zpn6n-source"

Notice the double hash in the name in the first version. Nix copied the flake into the store and eval’d code from there. When it referenced ./., it copied the directory back into the store again.

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