OK. This is a little odd, but what if a

fmt

tool adds a new file? Should that be reported in the list of changed files? Pants 2.12 shows the files that fmt changed, but the changed list only includes files that were present in both input and output digests. I dove into the code to figure out what does the diff. This is where the diff is displayed: https://github.com/pantsbuild/pants/blob/main/src/python/pants/core/goals/fmt.py#L116-L119 And this is where the actual diff happens, populating the list of

changed_files

: https://github.com/pantsbuild/pants/blob/main/src/rust/engine/fs/src/directory.rs#L599-L605 I believe that rust code only adds files to

changed_files

if the file is in both

ours

and

theirs

during diff... but I don't understand some of the syntax of rust, so I'm not sure.

Huh interesting! When would a formatter do this?

When codegen is masquerading as a formatter so that it is not restricted to

dist/codegen

and so that some schemas/specs (that get checked in) get auto-generated whenever their python deps change (without requiring manually running some command beyond the standard goals that people will be doing regularly).

@proud-dentist-22844 have you tested this with your changes? I'm wondering out the `Process`s output_files would work. Seems like it wouldn't capture it. Oh but you're making the process object. I see

fix

would make more sense. Using

fmt

for this feels wrong, but I don't want anyone to have to remember to extra commands if it can be avoided.

There's a proposal to rename

fmt

to

fix

, and then we'll add a

style-only

flag to it if you just want style. The gist is our tools do more than format (like your case), but semantic changes aren't always welcome (consider running

fix

on save, and it removes an import you just added, but havent used yet)

That makes sense. I'm cool with that. gofmt removing my imports is particularly irritating 😛 (or maybe it is Goland doing it, whatever), so the ability to do style-only could be useful.