doc(recipes): improve git integrated hidden files recipe (#470)

doc/recipes.md

@@ -30,47 +30,72 @@ require("oil").setup({
 })
 ```
 
-## Hide gitignored files
+## Hide gitignored files and show git tracked hidden files
 
 ```lua
-local git_ignored = setmetatable({}, {
-  __index = function(self, key)
-    local proc = vim.system(
-      { "git", "ls-files", "--ignored", "--exclude-standard", "--others", "--directory" },
-      {
+-- helper function to parse output
+local function parse_output(proc)
+  local result = proc:wait()
+  local ret = {}
+  if result.code == 0 then
+    for line in vim.gsplit(result.stdout, "\n", { plain = true, trimempty = true }) do
+      -- Remove trailing slash
+      line = line:gsub("/$", "")
+      ret[line] = true
+    end
+  end
+  return ret
+end
+
+-- build git status cache
+local function new_git_status()
+  return setmetatable({}, {
+    __index = function(self, key)
+      local ignore_proc = vim.system(
+        { "git", "ls-files", "--ignored", "--exclude-standard", "--others", "--directory" },
+        {
+          cwd = key,
+          text = true,
+        }
+      )
+      local tracked_proc = vim.system({ "git", "ls-tree", "HEAD", "--name-only" }, {
         cwd = key,
         text = true,
+      })
+      local ret = {
+        ignored = parse_output(ignore_proc),
+        tracked = parse_output(tracked_proc),
       }
-    )
-    local result = proc:wait()
-    local ret = {}
-    if result.code == 0 then
-      for line in vim.gsplit(result.stdout, "\n", { plain = true, trimempty = true }) do
-        -- Remove trailing slash
-        line = line:gsub("/$", "")
-        table.insert(ret, line)
-      end
-    end
 
-    rawset(self, key, ret)
-    return ret
-  end,
-})
+      rawset(self, key, ret)
+      return ret
+    end,
+  })
+end
+local git_status = new_git_status()
+
+-- Clear git status cache on refresh
+local refresh = require("oil.actions").refresh
+local orig_refresh = refresh.callback
+refresh.callback = function(...)
+  git_status = new_git_status()
+  orig_refresh(...)
+end
 
 require("oil").setup({
   view_options = {
     is_hidden_file = function(name, _)
-      -- dotfiles are always considered hidden
-      if vim.startswith(name, ".") then
-        return true
-      end
       local dir = require("oil").get_current_dir()
-      -- if no local directory (e.g. for ssh connections), always show
-      if not dir then
-        return false
+      local is_dotfile = vim.startswith(name, ".") and name ~= ".."
+      -- if no local directory (e.g. for ssh connections), just hide dotfiles
+      if not dir then return is_dotfile end
+      -- dotfiles are considered hidden unless tracked
+      if is_dotfile then
+        return not git_status[dir].tracked[name]
+      else
+        -- Check if file is gitignored
+        return git_status[dir].ignored[name]
       end
-      -- Check if file is gitignored
-      return vim.list_contains(git_ignored[dir], name)
     end,
   },
 })