Why is patdiff instructed to show unrefined diffs?

[hakuch]

Desired Behavior

When it's installed, Dune uses the patdiff utility to show diffs as part of, for example, expectation tests.

My understanding is that the value proposition of patdiff is that it shows more refined diffs than whole-line changes.

For example, a diff produced by patdiff could identify clearly a single integer being different on a line that's otherwise the same.

Current behavior

While there's an explicit check for patdiff being present here, the -unrefined flag is being passed to patdiff, which is counter-intuitive to me.

Is the reason for this performance? If so, I'd personally prefer that the default was to omit -unrefined and to make its inclusion an option exposed somehow in Dune.

[ghost]

That's a good question... I dig into the history and this argument was passed since the beginning. Seems like I just copy&pasted at the beginning from the way we were calling patdiff in ppx_expect. We should probably remove it.

[hakuch]

It's always a pleasure to know I asked a helpful question! 😃

Could I take a stab at fixing this with a PR? It might be a nice way to learn a little more about Dune development.

[ghost]

Definitely, thanks for asking and making a PR :)