feat(#2225): add renderer.hidden_display to show a summary of hidden files below the tree (#2856)

* feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

* feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

* feat(icon_placement): consolidate doc

* fix: extra namespace added to avoid colision between right_align and full_name features

* feat(hidden_display): Allow fine grained rendering of hidden files in
a folder

* feat(hidden_display): update defaults in Builder to allow rendering

* feat(hidden_display): Rename opts function name for the feature

* feat(#2349): add "right_align" option for renderer.icons.*_placement (#2846)

* feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

* feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

feat(icon_placement): Allow right_align icon_placemente for decorator using ext_marks nvim api

* feat(icon_placement): consolidate doc

* fix: extra namespace added to avoid colision between right_align and full_name features

* style: rename namespace_id

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>

* docs: update docs

* feat(hidden_display): Simplification and better performance by not sorting and grouping virtual lines

* Update doc/nvim-tree-lua.txt

Co-authored-by: Alexander Courtis <alex@courtis.org>

* style: hidden_stats is better

* docs: change to hidden_stats

* add separate namespace for virtual lines

* help: add highlight group

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>

doc/nvim-tree-lua.txt

@@ -423,6 +423,7 @@ Following is the default configuration. See |nvim-tree-opts| for details.
         root_folder_label = ":~:s?$?/..?",
         indent_width = 2,
         special_files = { "Cargo.toml", "Makefile", "README.md", "readme.md" },
+        hidden_display = "none",
         symlink_destination = true,
         highlight_git = "none",
         highlight_diagnostics = "none",
@@ -878,6 +879,49 @@ Number of spaces for an each tree nesting level. Minimum 1.
 A list of filenames that gets highlighted with `NvimTreeSpecialFile`.
   Type: `table`, Default: `{ "Cargo.toml", "Makefile", "README.md", "readme.md", }`
 
+*nvim-tree.renderer.hidden_display*
+Show a summary of hidden files below the tree using `NvimTreeHiddenDisplay
+  Type: `function | string`, Default: `"none"`
+
+  Possible string values are:
+    - `"none"`:   Doesn't inform anything about hidden files.
+    - `"simple"`: Shows how many hidden files are in a folder.
+    - `"all"`:    Shows how many files are hidden and the number of hidden
+                files per reason why they're hidden.
+
+  Example `"all"`:
+    If a folder has 14 hidden items for various reasons, the display might
+    show: >
+    (14 total git: 5, dotfile: 9)
+<
+  If a function is provided, it receives a table `hidden_stats` where keys are
+  reasons and values are the count of hidden files for that reason.
+
+  The `hidden_stats` argument is structured as follows, where <num> is the
+  number of hidden files related to the field: >
+    hidden_stats = {
+      bookmark = <num>,
+      buf = <num>,
+      custom = <num>,
+      dotfile = <num>,
+      git = <num>,
+      live_filter = <num>,
+    }
+<
+  Example of function that can be passed: >
+    function(hidden_stats)
+      local total_count = 0
+      for reason, count in pairs(hidden_stats) do
+        total_count = total_count + count
+      end
+
+      if total_count > 0 then
+        return "(" .. tostring(total_count) .. " hidden)"
+      end
+      return nil
+    end
+<
+
 *nvim-tree.renderer.symlink_destination*
 Whether to show the destination of the symlink.
   Type: `boolean`, Default: `true`
@@ -2461,6 +2505,9 @@ Hidden: >
     NvimTreeModifiedFileHL      NvimTreeHiddenIcon
     NvimTreeModifiedFolderHL    NvimTreeHiddenFileHL
 <
+Hidden Display: >
+    NvimTreeHiddenDisplay       Conceal
+<
 Opened: >
     NvimTreeOpenedHL            Special
 <
@@ -2872,6 +2919,7 @@ highlight group is not, hard linking as follows: >
 |nvim-tree.renderer.add_trailing|
 |nvim-tree.renderer.full_name|
 |nvim-tree.renderer.group_empty|
+|nvim-tree.renderer.hidden_display|
 |nvim-tree.renderer.highlight_bookmarks|
 |nvim-tree.renderer.highlight_clipboard|
 |nvim-tree.renderer.highlight_diagnostics|

lua/nvim-tree.lua

@@ -398,6 +398,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
     root_folder_label = ":~:s?$?/..?",
     indent_width = 2,
     special_files = { "Cargo.toml", "Makefile", "README.md", "readme.md" },
+    hidden_display = "none",
     symlink_destination = true,
     highlight_git = "none",
     highlight_diagnostics = "none",
@@ -647,6 +648,7 @@ local ACCEPTED_TYPES = {
     },
   },
   renderer = {
+    hidden_display = { "function", "string" },
     group_empty = { "boolean", "function" },
     root_folder_label = { "function", "string", "boolean" },
   },
@@ -680,6 +682,7 @@ local ACCEPTED_STRINGS = {
     signcolumn = { "yes", "no", "auto" },
   },
   renderer = {
+    hidden_display = { "none", "simple", "all" },
     highlight_git = { "none", "icon", "name", "all" },
     highlight_opened_files = { "none", "icon", "name", "all" },
     highlight_modified = { "none", "icon", "name", "all" },

lua/nvim-tree/appearance/init.lua

@@ -14,6 +14,7 @@ M.HIGHLIGHT_GROUPS = {
   -- Standard
   { group = "NvimTreeNormal", link = "Normal" },
   { group = "NvimTreeNormalFloat", link = "NormalFloat" },
+  { group = "NvimTreeNormalFloatBorder", link = "FloatBorder" },
   { group = "NvimTreeNormalNC", link = "NvimTreeNormal" },
 
   { group = "NvimTreeLineNr", link = "LineNr" },
@@ -81,6 +82,9 @@ M.HIGHLIGHT_GROUPS = {
   { group = "NvimTreeHiddenFileHL", link = "NvimTreeHiddenIcon" },
   { group = "NvimTreeHiddenFolderHL", link = "NvimTreeHiddenFileHL" },
 
+  -- Hidden Display
+  { group = "NvimTreeHiddenDisplay", link = "Conceal" },
+
   -- Opened
   { group = "NvimTreeOpenedHL", link = "Special" },
 

lua/nvim-tree/enum.lua

@@ -19,4 +19,15 @@ M.ICON_PLACEMENT = {
   right_align = 4,
 }
 
+---Reason for filter in filter.lua
+---@enum FILTER_REASON
+M.FILTER_REASON = {
+  none = 0, -- It's not filtered
+  git = 1,
+  buf = 2,
+  dotfile = 4,
+  custom = 8,
+  bookmark = 16,
+}
+
 return M

lua/nvim-tree/explorer/explore.lua

@@ -5,6 +5,7 @@ local git = require "nvim-tree.git"
 local live_filter = require "nvim-tree.live-filter"
 local log = require "nvim-tree.log"
 
+local FILTER_REASON = require("nvim-tree.enum").FILTER_REASON
 local Watcher = require "nvim-tree.watcher"
 
 local M = {}
@@ -17,7 +18,17 @@ local M = {}
 local function populate_children(handle, cwd, node, git_status, parent)
   local node_ignored = explorer_node.is_git_ignored(node)
   local nodes_by_path = utils.bool_record(node.nodes, "absolute_path")
+
   local filter_status = parent.filters:prepare(git_status)
+
+  node.hidden_stats = vim.tbl_deep_extend("force", node.hidden_stats or {}, {
+    git = 0,
+    buf = 0,
+    dotfile = 0,
+    custom = 0,
+    bookmark = 0,
+  })
+
   while true do
     local name, t = vim.loop.fs_scandir_next(handle)
     if not name then
@@ -29,8 +40,8 @@ local function populate_children(handle, cwd, node, git_status, parent)
 
     ---@type uv.fs_stat.result|nil
     local stat = vim.loop.fs_stat(abs)
-
+    local filter_reason = parent.filters:should_filter_as_reason(abs, stat, filter_status)
-    if not parent.filters:should_filter(abs, stat, filter_status) and not nodes_by_path[abs] and Watcher.is_fs_event_capable(abs) then
+    if filter_reason == FILTER_REASON.none and not nodes_by_path[abs] and Watcher.is_fs_event_capable(abs) then
       local child = nil
       if t == "directory" and vim.loop.fs_access(abs, "R") then
         child = builders.folder(node, abs, name, stat)
@@ -47,6 +58,12 @@ local function populate_children(handle, cwd, node, git_status, parent)
         nodes_by_path[child.absolute_path] = true
         explorer_node.update_git_status(child, node_ignored, git_status)
       end
+    else
+      for reason, value in pairs(FILTER_REASON) do
+        if filter_reason == value then
+          node.hidden_stats[reason] = node.hidden_stats[reason] + 1
+        end
+      end
     end
 
     log.profile_end(profile)

lua/nvim-tree/explorer/filters.lua

@@ -1,4 +1,5 @@
 local utils = require "nvim-tree.utils"
+local FILTER_REASON = require("nvim-tree.enum").FILTER_REASON
 
 ---@class Filters to handle all opts.filters and related API
 ---@field config table hydrated user opts.filters
@@ -223,4 +224,33 @@ function Filters:should_filter(path, fs_stat, status)
     or bookmark(self, path, fs_stat and fs_stat.type, status.bookmarks)
 end
 
+--- Check if the given path should be filtered, and provide the reason why it was
+---@param path string Absolute path
+---@param fs_stat uv.fs_stat.result|nil fs_stat of file
+---@param status table from prepare
+---@return FILTER_REASON
+function Filters:should_filter_as_reason(path, fs_stat, status)
+  if not self.config.enable then
+    return FILTER_REASON.none
+  end
+
+  if is_excluded(self, path) then
+    return FILTER_REASON.none
+  end
+
+  if git(self, path, status.git_status) then
+    return FILTER_REASON.git
+  elseif buf(self, path, status.bufinfo) then
+    return FILTER_REASON.buf
+  elseif dotfile(self, path) then
+    return FILTER_REASON.dotfile
+  elseif custom(self, path) then
+    return FILTER_REASON.custom
+  elseif bookmark(self, path, fs_stat and fs_stat.type, status.bookmarks) then
+    return FILTER_REASON.bookmark
+  else
+    return FILTER_REASON.none
+  end
+end
+
 return Filters

lua/nvim-tree/explorer/reload.lua

@@ -5,6 +5,7 @@ local live_filter = require "nvim-tree.live-filter"
 local git = require "nvim-tree.git"
 local log = require "nvim-tree.log"
 
+local FILTER_REASON = require("nvim-tree.enum").FILTER_REASON
 local NodeIterator = require "nvim-tree.iterators.node-iterator"
 local Watcher = require "nvim-tree.watcher"
 
@@ -92,6 +93,16 @@ function M.reload(node, git_status)
   local node_ignored = explorer_node.is_git_ignored(node)
   ---@type table<string, Node>
   local nodes_by_path = utils.key_by(node.nodes, "absolute_path")
+
+  -- To reset we must 'zero' everything that we use
+  node.hidden_stats = vim.tbl_deep_extend("force", node.hidden_stats or {}, {
+    git = 0,
+    buf = 0,
+    dotfile = 0,
+    custom = 0,
+    bookmark = 0,
+  })
+
   while true do
     local name, t = vim.loop.fs_scandir_next(handle)
     if not name then
@@ -102,7 +113,8 @@ function M.reload(node, git_status)
     ---@type uv.fs_stat.result|nil
     local stat = vim.loop.fs_stat(abs)
 
-    if not explorer.filters:should_filter(abs, stat, filter_status) then
+    local filter_reason = explorer.filters:should_filter_as_reason(abs, stat, filter_status)
+    if filter_reason == FILTER_REASON.none then
       remain_childs[abs] = true
 
       -- Recreate node if type changes.
@@ -139,6 +151,12 @@ function M.reload(node, git_status)
           n.fs_stat = stat
         end
       end
+    else
+      for reason, value in pairs(FILTER_REASON) do
+        if filter_reason == value then
+          node.hidden_stats[reason] = node.hidden_stats[reason] + 1
+        end
+      end
     end
   end
 

lua/nvim-tree/live-filter.lua

@@ -18,10 +18,17 @@ local function reset_filter(node_)
     return
   end
 
+  node_.hidden_stats = vim.tbl_deep_extend("force", node_.hidden_stats or {}, {
+    live_filter = 0,
+  })
+
   Iterator.builder(node_.nodes)
     :hidden()
     :applier(function(node)
       node.hidden = false
+      node.hidden_stats = vim.tbl_deep_extend("force", node.hidden_stats or {}, {
+        live_filter = 0,
+      })
     end)
     :iterate()
 end
@@ -79,6 +86,10 @@ function M.apply_filter(node_)
     local filtered_nodes = 0
     local nodes = node.group_next and { node.group_next } or node.nodes
 
+    node.hidden_stats = vim.tbl_deep_extend("force", node.hidden_stats or {}, {
+      live_filter = 0,
+    })
+
     if nodes then
       for _, n in pairs(nodes) do
         iterate(n)
@@ -88,6 +99,8 @@ function M.apply_filter(node_)
       end
     end
 
+    node.hidden_stats.live_filter = filtered_nodes
+
     local has_nodes = nodes and (M.always_show_folders or #nodes > filtered_nodes)
     local ok, is_match = pcall(matches, node)
     node.hidden = not (has_nodes or (ok and is_match))

lua/nvim-tree/node.lua

@@ -21,6 +21,7 @@
 ---@field group_next Node|nil
 ---@field nodes Node[]
 ---@field open boolean
+---@field hidden_stats table -- Each field of this table is a key for source and value for count
 
 ---@class FileNode: BaseNode
 ---@field extension string

lua/nvim-tree/renderer/builder.lua

@@ -43,6 +43,8 @@ local M = {
 ---@field lines string[] includes icons etc.
 ---@field hl_args AddHighlightArgs[] line highlights
 ---@field signs string[] line signs
+---@field extmarks table[] extra marks for right icon placement
+---@field virtual_lines table[] virtual lines for hidden count display
 ---@field private root_cwd string absolute path
 ---@field private index number
 ---@field private depth number
@@ -62,6 +64,7 @@ function Builder:new()
     markers = {},
     signs = {},
     extmarks = {},
+    virtual_lines = {},
   }
   setmetatable(o, self)
   self.__index = self
@@ -351,7 +354,6 @@ function Builder:build_line(node, idx, num_children)
   self.index = self.index + 1
 
   node = require("nvim-tree.lib").get_last_group_node(node)
-
   if node.open then
     self.depth = self.depth + 1
     self:build_lines(node)
@@ -359,6 +361,32 @@ function Builder:build_line(node, idx, num_children)
   end
 end
 
+---Add virtual lines for rendering hidden count information per node
+---@private
+function Builder:add_hidden_count_string(node, idx, num_children)
+  if not node.open then
+    return
+  end
+  local hidden_count_string = M.opts.renderer.hidden_display(node.hidden_stats)
+  if hidden_count_string and hidden_count_string ~= "" then
+    local indent_markers = pad.get_indent_markers(self.depth, idx or 0, num_children or 0, node, self.markers, 1)
+    local indent_width = M.opts.renderer.indent_width
+
+    local indent_padding = string.rep(" ", indent_width)
+    local indent_string = indent_padding .. indent_markers.str
+    local line_nr = #self.lines - 1
+    self.virtual_lines[line_nr] = self.virtual_lines[line_nr] or {}
+
+    -- NOTE: We are inserting in depth order because of current traversal
+    -- if we change the traversal, we might need to sort by depth before rendering `self.virtual_lines`
+    -- to maintain proper ordering of parent and child folder hidden count info.
+    table.insert(self.virtual_lines[line_nr], {
+      { indent_string, indent_markers.hl },
+      { string.rep(indent_padding, (node.parent == nil and 0 or 1)) .. hidden_count_string, "NvimTreeHiddenDisplay" },
+    })
+  end
+end
+
 ---@private
 function Builder:get_nodes_number(nodes)
   if not live_filter.filter then
@@ -388,6 +416,7 @@ function Builder:build_lines(node)
       idx = idx + 1
     end
   end
+  self:add_hidden_count_string(node)
 end
 
 ---@private
@@ -442,7 +471,50 @@ function Builder:build()
   return self
 end
 
+---@param opts table
+local setup_hidden_display_function = function(opts)
+  local hidden_display = opts.renderer.hidden_display
+  -- options are already validated, so ´hidden_display´ can ONLY be `string` or `function` if type(hidden_display) == "string" then
+  if type(hidden_display) == "string" then
+    if hidden_display == "none" then
+      opts.renderer.hidden_display = function()
+        return nil
+      end
+    elseif hidden_display == "simple" then
+      opts.renderer.hidden_display = function(hidden_stats)
+        return utils.default_format_hidden_count(hidden_stats, true)
+      end
+    elseif hidden_display == "all" then
+      opts.renderer.hidden_display = function(hidden_stats)
+        return utils.default_format_hidden_count(hidden_stats, false)
+      end
+    end
+  elseif type(hidden_display) == "function" then
+    local safe_render = function(hidden_stats)
+      -- In case of missing field such as live_filter we zero it, otherwise keep field as is
+      hidden_stats = vim.tbl_deep_extend("force", {
+        live_filter = 0,
+        git = 0,
+        buf = 0,
+        dotfile = 0,
+        custom = 0,
+        bookmark = 0,
+      }, hidden_stats or {})
+
+      local ok, result = pcall(hidden_display, hidden_stats)
+      if not ok then
+        notify.warn "Problem occurred in the function ``opts.renderer.hidden_display`` see nvim-tree.renderer.hidden_display on :h nvim-tree"
+        return nil
+      end
+      return result
+    end
+
+    opts.renderer.hidden_display = safe_render
+  end
+end
+
 function Builder.setup(opts)
+  setup_hidden_display_function(opts)
   M.opts = opts
 
   -- priority order

lua/nvim-tree/renderer/components/padding.lua

@@ -19,7 +19,7 @@ local function check_siblings_for_folder(node, with_arrows)
   return false
 end
 
-local function get_padding_indent_markers(depth, idx, nodes_number, markers, with_arrows, inline_arrows, node)
+local function get_padding_indent_markers(depth, idx, nodes_number, markers, with_arrows, inline_arrows, node, early_stop)
   local base_padding = with_arrows and (not node.nodes or depth > 0) and "  " or ""
   local padding = (inline_arrows or depth == 0) and base_padding or ""
 
@@ -27,7 +27,7 @@ local function get_padding_indent_markers(depth, idx, nodes_number, markers, wit
     local has_folder_sibling = check_siblings_for_folder(node, with_arrows)
     local indent = string.rep(" ", M.config.indent_width - 1)
     markers[depth] = idx ~= nodes_number
-    for i = 1, depth do
+    for i = 1, depth - early_stop do
       local glyph
       if idx == nodes_number and i == depth then
         local bottom_width = M.config.indent_width - 2 + (with_arrows and not inline_arrows and has_folder_sibling and 2 or 0)
@@ -62,7 +62,7 @@ end
 ---@param node table
 ---@param markers table
 ---@return HighlightedString[]
-function M.get_indent_markers(depth, idx, nodes_number, node, markers)
+function M.get_indent_markers(depth, idx, nodes_number, node, markers, early_stop)
   local str = ""
 
   local show_arrows = M.config.icons.show.folder_arrow
@@ -71,7 +71,7 @@ function M.get_indent_markers(depth, idx, nodes_number, node, markers)
   local indent_width = M.config.indent_width
 
   if show_markers then
-    str = str .. get_padding_indent_markers(depth, idx, nodes_number, markers, show_arrows, inline_arrows, node)
+    str = str .. get_padding_indent_markers(depth, idx, nodes_number, markers, show_arrows, inline_arrows, node, early_stop or 0)
   else
     str = str .. string.rep(" ", depth * indent_width)
   end

lua/nvim-tree/renderer/init.lua

@@ -14,12 +14,13 @@ local SIGN_GROUP = "NvimTreeRendererSigns"
 
 local namespace_highlights_id = vim.api.nvim_create_namespace "NvimTreeHighlights"
 local namespace_extmarks_id = vim.api.nvim_create_namespace "NvimTreeExtmarks"
+local namespace_virtual_lines_id = vim.api.nvim_create_namespace "NvimTreeVirtualLines"
 
 ---@param bufnr number
 ---@param lines string[]
 ---@param hl_args AddHighlightArgs[]
 ---@param signs string[]
-local function _draw(bufnr, lines, hl_args, signs, extmarks)
+local function _draw(bufnr, lines, hl_args, signs, extmarks, virtual_lines)
   if vim.fn.has "nvim-0.10" == 1 then
     vim.api.nvim_set_option_value("modifiable", true, { buf = bufnr })
   else
@@ -50,6 +51,15 @@ local function _draw(bufnr, lines, hl_args, signs, extmarks)
       })
     end
   end
+
+  vim.api.nvim_buf_clear_namespace(bufnr, namespace_virtual_lines_id, 0, -1)
+  for line_nr, vlines in pairs(virtual_lines) do
+    vim.api.nvim_buf_set_extmark(bufnr, namespace_virtual_lines_id, line_nr, 0, {
+      virt_lines = vlines,
+      virt_lines_above = false,
+      virt_lines_leftcol = true,
+    })
+  end
 end
 
 function M.render_hl(bufnr, hl)
@@ -79,7 +89,7 @@ function M.draw()
 
   local builder = Builder:new():build()
 
-  _draw(bufnr, builder.lines, builder.hl_args, builder.signs, builder.extmarks)
+  _draw(bufnr, builder.lines, builder.hl_args, builder.signs, builder.extmarks, builder.virtual_lines)
 
   if cursor and #builder.lines >= cursor[1] then
     vim.api.nvim_win_set_cursor(view.get_winnr() or 0, cursor)

lua/nvim-tree/utils.lua

@@ -181,6 +181,26 @@ function M.get_parent_of_group(node)
   return node
 end
 
+M.default_format_hidden_count = function(hidden_count, simple)
+  local parts = {}
+  local total_count = 0
+  for reason, count in pairs(hidden_count) do
+    total_count = total_count + count
+    if count > 0 then
+      table.insert(parts, reason .. ": " .. tostring(count))
+    end
+  end
+
+  local hidden_count_string = table.concat(parts, ", ") -- if empty then is "" (empty string)
+  if simple then
+    hidden_count_string = ""
+  end
+  if total_count > 0 then
+    return "(" .. tostring(total_count) .. (simple and " hidden" or " total ") .. hidden_count_string .. ")"
+  end
+  return nil
+end
+
 --- Return visible nodes indexed by line
 ---@param nodes_all Node[]
 ---@param line_start number

lua/nvim-tree/view.lua

@@ -50,6 +50,7 @@ M.View = {
       "Normal:NvimTreeNormal",
       "NormalNC:NvimTreeNormalNC",
       "NormalFloat:NvimTreeNormalFloat",
+      "FloatBorder:NvimTreeNormalFloatBorder",
     }, ","),
   },
 }