feat(fs): add vim.fs.parents()

vim.fs.parents() is a Lua iterator that returns the next parent
directory of the given file or directory on each iteration.

3 files changed, 64 insertions, 0 deletions

diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
index dd1843ade3..8f74dca418 100644
--- a/runtime/doc/lua.txt
+++ b/runtime/doc/lua.txt
@@ -2147,4 +2147,32 @@ set({mode}, {lhs}, {rhs}, {opts})                           *vim.keymap.set()*
                 See also: ~
                     |nvim_set_keymap()|
 
+
+==============================================================================
+Lua module: fs                                                        *lua-fs*
+
+parents({start})                                            *vim.fs.parents()*
+                Iterate over all the parents of the given file or directory.
+
+                Example: >
+
+                 local root_dir
+                 for dir in vim.fs.parents(vim.api.nvim_buf_get_name(0)) do
+                   if vim.fn.isdirectory(dir .. "/.git") == 1 then
+                     root_dir = dir
+                     break
+                   end
+                 end
+
+                 if root_dir then
+                   print("Found git repository at", root_dir)
+                 end
+<
+
+                Parameters: ~
+                    {start}  (string) Initial file or directory.
+
+                Return: ~
+                    (function) Iterator
+
  vim:tw=78:ts=8:ft=help:norl:
diff --git a/runtime/lua/vim/_editor.lua b/runtime/lua/vim/_editor.lua
index c8a0aa8260..453aa6ac81 100644
--- a/runtime/lua/vim/_editor.lua
+++ b/runtime/lua/vim/_editor.lua
@@ -50,6 +50,7 @@ for k, v in pairs({
   keymap = true,
   ui = true,
   health = true,
+  fs = true,
 }) do
   vim._submodules[k] = v
 end
diff --git a/runtime/lua/vim/fs.lua b/runtime/lua/vim/fs.lua
new file mode 100644
index 0000000000..08d2e495d2
--- /dev/null
+++ b/runtime/lua/vim/fs.lua
@@ -0,0 +1,35 @@
+local M = {}
+
+--- Iterate over all the parents of the given file or directory.
+---
+--- Example:
+--- <pre>
+--- local root_dir
+--- for dir in vim.fs.parents(vim.api.nvim_buf_get_name(0)) do
+---   if vim.fn.isdirectory(dir .. "/.git") == 1 then
+---     root_dir = dir
+---     break
+---   end
+--- end
+---
+--- if root_dir then
+---   print("Found git repository at", root_dir)
+--- end
+--- </pre>
+---
+---@param start (string) Initial file or directory.
+---@return (function) Iterator
+function M.parents(start)
+  return function(_, dir)
+    local parent = vim.fn.fnamemodify(dir, ":h")
+    if parent == dir then
+      return nil
+    end
+
+    return parent
+  end,
+    nil,
+    start
+end
+
+return M