Help with custom command, opening file from branch using fugitive `Gvsplit`

[ibhagwan]

Context: https://www.reddit.com/r/neovim/comments/vu7v92/custom_complete_for_nvim_create_user_command/

@pure-bliss, let me know if you need more help with this.

Notes:

• For file type entries I prefer using files to fzf_exec, you get the benefit of multiprocessing (running the command in an external process) as wel as automatic entry processing (icons, relative paths, shortening paths, etc) so you can also skip calling fn_transform and make_entry.file since these will be done automatically for you
• With files we also get the automatic previewer and action configurations, that's why I disabled both default and ctrl-s actions, assuming OP doesn't need/want those
• When using file icons (either through files or fn_transform) the selected array will now contain entries with icons which must be stripped with path.entry_to_file before being sent to to the fugitive command
• During development, I highly recommend using vim.pretty_print at strategic locations so you can inspect the contents of ceratain objects, use ':messages' to inspect the output of objects containing more than one line

vim.api.nvim_create_user_command(
  'ListFilesFromBranch',
  function(opts)
    require 'fzf-lua'.files({
      cmd = "git ls-tree -r --name-only " .. opts.args,
      prompt = opts.args .. "> ",
      actions = {
        ['default'] = false,
        ['ctrl-s'] = false,
        ['ctrl-v'] = function(selected, o)
          -- use vim.pretty_print to see what's inside objects:
          -- vim.pretty_print(selected)
          local file = require'fzf-lua'.path.entry_to_file(selected[1], o)
          local cmd = string.format("Gvsplit %s:%s", opts.args, file.path)
          print("running:", cmd)
          vim.cmd(cmd)
          vim.cmd("windo diffthis")
        end
      },
    })
  end,
  {
    nargs = 1,
    force = true,
    complete = function()
      local branches = vim.fn.systemlist("git branch --all --sort=-committerdate")
      if vim.v.shell_error == 0 then
        return vim.tbl_map(function(x)
          return x:match("[^%s%*]+"):gsub("^remotes/", "")
        end, branches)
      end
    end,
  })

[pure-bliss]

Many thanks for the help :) This is just what I was trying to achieve. Will only have time on Monday to put it to a use, but was able to play it with a bit.

The only minor issue I found is that I think the preview window doesn't show the correct content of the file on the branch given, it shows the version which is on the current branch. Furthermore preview won't load for files that only exists on the inspected branch. I think I'll have to further investigate the wiki (https://github.com/ibhagwan/fzf-lua/wiki/Advanced#preview-overview) in attempt to make it work, but in my use case I'm sure I won't need the preview window, so its not a problem at all, and will probably disable it.

Thanks again for the help, and the awesome plugin!

[ibhagwan]

The only minor issue I found is that I think the preview window doesn't show the correct content of the file on the branch given, it shows the version which is on the current branch. Furthermore preview won't load for files that only exists on the inspected branch. I think I'll have to further investigate the wiki (https://github.com/ibhagwan/fzf-lua/wiki/Advanced#preview-overview) in attempt to make it work, but in my use case I'm sure I won't need the preview window, so its not a problem at all, and will probably disable it.

You're absolutely correct, the file previewer shows content directly from the file-system this will require a different approach by using git show instead:

vim.api.nvim_create_user_command(
  'ListFilesFromBranch',
  function(opts)
    require 'fzf-lua'.files({
      cmd = "git ls-tree -r --name-only " .. opts.args,
      prompt = opts.args .. "> ",
      actions = {
        ['default'] = false,
        ['ctrl-s'] = false,
        ['ctrl-v'] = function(selected, o)
          -- use vim.pretty_print to see what's inside objects:
          -- vim.pretty_print(selected)
          local file = require'fzf-lua'.path.entry_to_file(selected[1], o)
          local cmd = string.format("Gvsplit %s:%s", opts.args, file.path)
          print("running:", cmd)
          vim.cmd(cmd)
          vim.cmd("windo diffthis")
        end,
      },
      -- disable the file previewer so we can use fzf's previewer instead
      previewer = false,
      preview = require'fzf-lua'.shell.raw_preview_action_cmd(function(items)
        local file = require'fzf-lua'.path.entry_to_file(items[1])
        return string.format("git show %s:%s | bat", opts.args, file.path)
      end)
    })
  end,
  {
    nargs = 1,
    force = true,
    complete = function()
      local branches = vim.fn.systemlist("git branch --all --sort=-committerdate")
      if vim.v.shell_error == 0 then
        return vim.tbl_map(function(x)
          return x:match("[^%s%*]+"):gsub("^remotes/", "")
        end, branches)
      end
    end,
  })

[pure-bliss]

Yes, this is perfect! I over complicated, and thought about making it work with with the built in previewer, so treesitter and everything works, but this is just as good :) Thanks again :)

[ibhagwan]

Yes, this is perfect! I over complicated, and thought about making it work with with the built in previewer, so treesitter and everything works, but this is just as good :) Thanks again :)

It’s possible, but as you mentioned would complicate things a bit, especially since the builtin previewer API wasn’t reworked yet and isn’t not as straight forward as the Fzf preview.

I do however think there may be an improvement here that would be even better: what if instead of using git show you use git diff --color=always <branch> HEAD -- <file> or better yet it git diff <branch> HEAD -- <file> | delta, this way you can see the diff in the preview and don’t even have to press ctrl-v unless you’re interested in this specific change?

[ibhagwan]

I just tested this myself, it's actually quite lovely to explore changes in files from a specific branch (vs HEAD) like this, delta makes it extra nice:

vim.api.nvim_create_user_command(
  'ListFilesFromBranch',
  function(opts)
    require 'fzf-lua'.files({
      cmd = "git ls-tree -r --name-only " .. opts.args,
      prompt = opts.args .. "> ",
      actions = {
        ['default'] = false,
        ['ctrl-s'] = false,
        ['ctrl-v'] = function(selected, o)
          local file = require'fzf-lua'.path.entry_to_file(selected[1], o)
          local cmd = string.format("Gvsplit %s:%s", opts.args, file.path)
          vim.cmd(cmd)
        end,
      },
      previewer = false,
      preview = require'fzf-lua'.shell.raw_preview_action_cmd(function(items)
        local file = require'fzf-lua'.path.entry_to_file(items[1])
        return string.format("git diff %s HEAD -- %s | delta", opts.args, file.path)
      end)
    })
  end,
  {
    nargs = 1,
    force = true,
    complete = function()
      local branches = vim.fn.systemlist("git branch --all --sort=-committerdate")
      if vim.v.shell_error == 0 then
        return vim.tbl_map(function(x)
          return x:match("[^%s%*]+"):gsub("^remotes/", "")
        end, branches)
      end
    end,
  })

[ibhagwan]

Added to the Wiki as the first advanced user example:

https://github.com/ibhagwan/fzf-lua/wiki/Advanced#user-examples

[pure-bliss]

Nice, I hope other finds this useful too :) I think what the preview shows is a personal preference, and fortunately can be changed easily. I'll have to use it for a bit to see which preview suits me the most. But its really good, that we can change the content of the preview easily!

[ibhagwan]

Closing this, let me know if you ever need more help.