Feature Request: Preview output

[Dynge]

I would love to be able to preview the output and maybe even edit the output arbitrarily.

Is this something that can be achieved? Kind of like the meld-3 merge tool.

[julienvincent]

Yea I would like this too actually. Not sure if I'll ever get around to this anytime soon, but agreed it would be nice.

If you or anyone else have thoughts on how to make this UX nice please feel free to comment it here.

[Dynge]

I would love to help making it. Can you guide me in the direction of the code that would need to be updated?

As i understand it jj supplies two directories, would we need to make a third copy of that or what?

[julienvincent]

Sure I'd love to accept some contributions to this effect!

One thing I want to note up front, just to set expectations: This feature would make up a pretty critical part of the overall UX of this plugin and so it will be worth discussing here and coming to agreement on the overall approach and user experience first.

But of course if you just want to get your hands dirty with it first that makes a lot of sense -
I just can't promise I will be accepting any PR's if I'm not happy with the actual UX of the feature.

But sometimes it's easier to play with the code before good ideas come flowing.

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So in terms of code, the most relevant part to familiarize yourself with right now is probably this section:

hunk.nvim/lua/hunk/api/changeset.lua

Line 102 in c21f15d

function M.write_changeset(changeset, output_dir)

It's responsible for taking a Changeset (a group of in-memory changes to files) and writing them to the output directory.

The changeset contains the diff hunks and all the individual line and file selections the user made. The function which writes these first performs an in-memory merge of any partially selected files before writing the output.

This all gets called from here

We would want to rework this in a way that the merge can go through some state where the user can modify the output before writing it to disk.

Not sure when exactly we want to do this.

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Another consideration - there is probably quite a lot of overlap between this feature request and #6 - which is all about merge conflict resolution.

It's worth considering this and how we can possibly make this feature be usable for solving that feature request as well. The problem for #6 is kind of the same:

• Select some lines from left and right
• Fix the result

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Perhaps unachievable, but what would be really sick is if we can build something like what Intellij Idea does for conflict resolution. They present a three-way diff, the ancestor in the middle, and allow merging left and right into the ancestor. You can also edit the middle buffer as you go. No idea how they do this, sounds like a nightmare. But maybe with some thought it can be possible.

I guess the easiest way to do this is to do a two part flow where you first select lines, then accept, then get presented with the result which you can modify. Easy to do (relatively) but probably not the nicest UX.

[Dynge]

I agree with the ux of a 3 way diff/merge is the way to go.

I wonder if you can't do some implementation leveraging the diffget and diffput vim commands.

I am not entirely sure how they function but I think it is what the diffview.nvim plugin is doing with git merges.