How can I limit the number of commits shown in the git log preview in git_branches

[dbatten5]

I work in a mono repo with a lot of commits and opening up the git_branches picker is really slow due to loading all the commit history for a branch I move the cursor to. How can I limit the number of commits shown in the preview window?

[drowning-cat]

git <args> log

picker.opts.previewers.git.args will be passed to the git_log previewer.

snacks.nvim/lua/snacks/picker/preview.lua

Lines 306 to 349 in bc0630e

	---@param ctx snacks.picker.preview.ctx
	local function git(ctx, ...)
	local ret = { "git", "-c", "delta." .. vim.o.background .. "=true" }
	vim.list_extend(ret, ctx.picker.opts.previewers.git.args or {})
	vim.list_extend(ret, { ... })
	return ret
	end
	---@param ctx snacks.picker.preview.ctx
	function M.git_log(ctx)
	local cmd = git(
	ctx,
	"--no-pager",
	"log",
	"--pretty=format:%h %s (%ch)",
	"--abbrev-commit",
	"--decorate",
	"--date=short",
	"--color=never",
	"--no-show-signature",
	"--no-patch",
	ctx.item.commit
	)
	local row = 0
	M.cmd(cmd, ctx, {
	ft = "git",
	---@param text string
	add = function(text)
	local commit, msg, date = text:match("^(%S+) (.*) %((.*)%)$")
	if commit then
	row = row + 1
	local hl = Snacks.picker.format.git_log({
	idx = 1,
	score = 0,
	text = "",
	commit = commit,
	msg = msg,
	date = date,
	}, ctx.picker)
	Snacks.picker.highlight.set(ctx.buf, ns, row, hl)
	end
	end,
	})
	end

---

git log <args>

Yes, we need to override the whole preview to append arguments to the underlying preview cmd.

picker = {
  sources = {
    git_branches = {
      preview = function(ctx)
        local ns = vim.api.nvim_create_namespace 'snacks.picker.preview'
        local M = require 'snacks.picker.preview'
        ---@param ctx snacks.picker.preview.ctx
        local function git(ctx, ...)
          local ret = { 'git', '-c', 'delta.' .. vim.o.background .. '=true' }
          vim.list_extend(ret, ctx.picker.opts.previewers.git.args or {})
          vim.list_extend(ret, { ... })
          return ret
        end
        local cmd = git(
          ctx,
          '--no-pager',
          'log',
          '--pretty=format:%h %s (%ch)',
          '--abbrev-commit',
          '--decorate',
          '--date=short',
          '--color=never',
          '--no-show-signature',
          '--no-patch',
          '--max-count=5', -- New! Limit the number of commits shown
          ctx.item.commit
        )
        local row = 0
        M.cmd(cmd, ctx, {
          ft = 'git',
          ---@param text string
          add = function(text)
            local commit, msg, date = text:match '^(%S+) (.*) %((.*)%)$'
            if commit then
              row = row + 1
              local hl = Snacks.picker.format.git_log({
                idx = 1,
                score = 0,
                text = '',
                commit = commit,
                msg = msg,
                date = date,
              }, ctx.picker)
              Snacks.picker.highlight.set(ctx.buf, ns, row, hl)
            end
          end,
        })
      end,

[dbatten5]

Thanks @drowning-cat. Feels a little clunky to have to overwrite the entire preview though, I'll raise an issue and hopefully it can be supported at a higher level

[dpetka2001]

local function git(ctx, ...) 
   local ret = { "git", "-c", "delta." .. vim.o.background .. "=true" } 
   vim.list_extend(ret, ctx.picker.opts.previewers.git.args or {}) 
   vim.list_extend(ret, { ... }) 
   return ret 
 end 

Doesn't the line vim.list_extend(ret, ctx.picker.opts.previewers.git.args or {}) mean that we can do something like

opts.picker.sources.git_branches = {
            previewers = {
              git = {
                args = { "--max-count=5" },
              },
            },
          },

Have you tried this?

[drowning-cat]

The problem is where these arguments go. It's like git --max-count=5 log instead of git log --max-count=5.

[dpetka2001]

Oh I see. Tnx for pointing this out.