numtide/treefmt compatibility

[yorickvP]

User report:

I set up treefmt for my editor and nixfmt fails formatting without any obvious sign.
Maybe the spec is incomplete, but I think it had to do with some sort of temp-file mutation. iirc.
Maybe treefmt and nixfmt are competing on the file-handling domain in incompatible ways?

[yorickvP]

@blaggacao

[SebTM]

I would like to hijack this as nixfmt was added by me to treefmt without seeing this - it works fine (from formatting output) but it changes mtime even file didn't had to be reformatted which was reported here and violates the idempotence requirement from treefmt.

Sadly I don't have any Haskell knowledge and currently no time to get into so I would appreciate if someone could help out here ✌️