FR: git commit --verbose equivalent for jj describe

[sullyj3]

Often when writing a commit message, it's useful to be able to see the diff at a glance. Git has git commit --verbose, which displays the diff inline in your editor while you're writing the message. This saves having to try to remember what changes you made.
I personally use this all the time. I have

alias gca='git commit --all --verbose'

which I use for committing almost exclusively.

It would be cool if jj supported this as well! I'm not wedded to the name --verbose, which I think could be clearer (and in fact looking at the help it conflicts with an existing flag with different functionality). Maybe --show-diff?

[ilyagr]

This could apply to quite a few commands (describe, split, squash, etc)

[martinvonz]

Maybe we can have a configurable template for producing that. We currently include something like this:

JJ: This commit contains the following changes:
JJ:     M lib/src/working_copy.rs
JJ:     M lib/tests/test_working_copy.rs

Maybe that could be replaced by a template like "This commit contains the following changes:\n" ++ indent(" ", diffsummary), and you could replace the diffsummary by diff (or gitdiff, perhaps) to get the full diff.

We don't yet have support for including a diff in templates, so we'd need to implement that first.

#1354 is slightly related.

[9999years]

I went looking for this feature, remembered jj has templates, and was a little surprised that jj describe didn't have a --template option for this yet, so I think templates would be a natural place to implement this. (Although I suspect this is a common enough use-case that a dedicated flag might be worthwhile, even if it's just an alias for --template=commit-with-diff or something.)

[Cretezy]

Looking for consensus before implementing this:

1. Should we use --show-diff for diff/squash/split?
2. Should we instead use a template feature for this?
3. If using template, how will this be used? Will jj ship with a built-in template for this?

[yuja]

1. Should we use --show-diff for diff/squash/split?

I think config knob is better. It was discussed previously in
#3470 (comment)

2. Should we instead use a template feature for this?

Template is preferred because it can solve other problems (such as #1354 and #3385), but it's not easy. I think adding a diff formatting option is also good as a short-term workaround.

3. If using template, how will this be used? Will jj ship with a built-in template for this?

Yeah. Perhaps, the default ui.default-description will be a template like

concat(
  description,
  "\n",
  "JJ: This commit contains the following changes:\n",
  indent("JJ:     ", format_diff_in_commit_description(diff)),
)

and format_diff_in_commit_description() will be customized by user.

[yuja]

Template is preferred because it can solve other problems (such as #1354 and #3385), but it's not easy.

FWIW, I'm working on commit.diff([paths]) template function, and I think a basic version can be added soon.

[lukerandall]

For those who stumble upon this; the nearest equivalent (since #4153) is to add something like this to your config file:

[templates]
draft_commit_description = '''
concat(
  description,
  surround(
    "\nJJ: This commit contains the following changes:\n", "",
    indent("JJ:     ", diff.stat(72)),
  ),
  surround(
    "\nJJ: Diff:\n", "",
    indent("JJ:     ", diff.git(3)),
  ),
)
'''

or if you don't want it all the time add an alias using --config-toml (in this example I use a template-alias to make the alias easier to read):

[aliases]
diffscribe = [
  "describe",
  "--config-toml=templates.draft_commit_description=\"commit_description_with_diff\"",
]

[template-aliases]
commit_description_with_diff = '''
concat(
  description,
  surround(
    "\nJJ: This commit contains the following changes:\n", "",
    indent("JJ:     ", diff.stat(72)),
  ),
  surround(
    "\nJJ: Diff:\n", "",
    indent("JJ:     ", diff.git()),
  ),
)
'''

The most notable deficiency is that you don't get diff highlighting in your text editor like you would with a git commit diff because of the prefixed JJ:.

Edited to fix git(72) → git() as noted by @tbodt below.

[tbodt]

 surround(
   "\nJJ: Diff:\n", "",
   indent("JJ:     ", diff.git(72)),
 ),

Important note - you almost certainly don't want diff.git(72), because the 72 becomes the number of lines of diff context! diff.git() appears to default to 3 lines of context which is fine.

[bryceberger]

Since #5155, you can now do something like:

[template-aliases]
commit_description_verbose = '''
concat(
  description,
  "\n",
  "JJ: This commit contains the following changes:\n",
  indent("JJ:    ", diff.stat(72)),
  "JJ: ignore-rest\n",
  diff.git(),
)
'''

[aliases]
dv = ["--config=templates.draft_commit_description=commit_description_verbose", "describe"]

[yuja]

Thanks. I think we can now close this issue?

[oyarsa]

This doesn't highlight changes in Vim like git commit --verbose does (additions are green, and removals are red). Is it possible to do that?

[Samasaur1]

I got that working in Neovim with a jjdescription tree-sitter plugin, so it's definitely possible

[oyarsa]

I got that working in Neovim with a jjdescription tree-sitter plugin, so it's definitely possible

Could you give more details?

[pylbrecht]

This is just based on a few minutes of research, but you might be able to add this jj-description grammar by following treesitter's instuctions on adding parsers.

[pylbrecht]

Here is a quick and dirty solution for lazy.nvim.

1. Add the jjdescription parser to nvim-treesitter.

   Add this to your lazy plugin spec (using lazy.nvim's structured setup):

   {
    'nvim-treesitter/nvim-treesitter',
     config = function()
       local parser_config = require "nvim-treesitter.parsers".get_parser_configs()
       parser_config.jjdescription = {
         install_info = {
           url = "https://github.com/kareigu/tree-sitter-jjdescription",
           files = { "src/parser.c" },
           branch = "dev",
         },
         filetype = "jj",
       }
       vim.treesitter.language.register('jjdescription', 'jj')
     end,
   }

   (See https://github.com/nvim-treesitter/nvim-treesitter?tab=readme-ov-file#adding-parsers for reference.)

2. Manually add query files to your local nvim-treesitter installation.

   I did this by manually copying tree-sitter-jjdescription’s query files to ~/.local/share/nvim/lazy/nvim-treesitter/queries/jjdescription/.

   (See https://github.com/nvim-treesitter/nvim-treesitter?tab=readme-ov-file#adding-queries for reference.)

3. Start nvim and :TSInstall jjdescription

Using the config from #1946 (comment) you should see a colorful diff (assuming you have changes in your working copy) when running

$ jj dv

---

There is still room for improvement (e.g. automating the manual copying of query files), but I hope this serves as a good starting point anyway.

[Samasaur1]

Sorry, was out and about. @pylbrecht got it exactly right. My config is with Nix, so it's probably harder to apply, but I can post the diff of my config if you'd like

[Samasaur1]

One other thing I did was setting:

[templates]
draft_commit_description = '''
concat(
  description,
  surround(
    "\nJJ: This commit contains the following changes:\n", "",
    indent("JJ:     ", diff.summary()),
  ),
  surround(
    "\nJJ: This commit contains the following changes:\n", "",
    indent("JJ:     ", diff.stat(72)),
  ),
  "\n",
  "JJ: ignore-rest\n",
  diff.git(),
)
'''

so that normal jj commit and jj describe use the verbose form. That's obviously personal preference though.

Also worth noting that if you use diff.summary() instead of diff.stat(72), the tree-sitter plugin will highlight that as well

[stacyharper]

For those using Kakoune, here the simplest but working filetype:

https://git.sr.ht/~stacyharper/dotfiles/tree/master/item/.config/kak/autoload/user/jj.kak

[gpanders]

FYI both Vim and Neovim support jj description syntax highlighting, including the diff syntax now vim/vim#16364 No tree-sitter or plugins required.

[Samasaur1]

FYI both Vim and Neovim support jj description syntax highlighting, including the diff syntax now vim/vim#16364 No tree-sitter or plugins required.

Am I correct that this needs latest Neovim master/the upcoming v0.10.4?

[gpanders]

Am I correct that this needs latest Neovim master/the upcoming v0.10.4?

Yes