Omitting `input.<name>.flake` from the written flake.nix

[mightyiam]

I've just encountered a scenario:

1. Using flake-file, write a flake with an input with flake=false.
2. Modify that input to have flake=true and write the flake.

Expected behavior: the input in the lockfile now has flake=true (or at least not flake=false, whatever).

Actual behavior: after step two, the lockfile remains the same as it was before step two.

Turns out we shouldn't omit the flake attribute when it's true 🤷

[mightyiam]

This might not be a flake-file issue. It seems that even setting flake = true is not enough to trigger a change in an existing locked input... which sounds like a bug in Nix to me.

[theutz]

Oh interesting! Yeah, that is very surprising behavior indeed.