feat(vim.fs): dir() ergonomics

1 files changed, 47 insertions, 54 deletions

diff --git a/runtime/lua/vim/fs.lua b/runtime/lua/vim/fs.lua
index 5dd87816b0..fc18d525dd 100644
--- a/runtime/lua/vim/fs.lua
+++ b/runtime/lua/vim/fs.lua
@@ -177,6 +177,10 @@ end
 --- (default: `1`)
 --- @field depth? integer
 ---
+--- Report errors via the iterator's third value ("err"), instead of silently skipping.
+--- (default: `false`)
+--- @field err? boolean
+---
 --- Predicate to control traversal.
 --- Return false to stop searching the current directory.
 --- Only useful when depth > 1
@@ -187,21 +191,14 @@ end
 --- (default: `false`)
 --- @field follow? boolean
 
-
 --- Gets an iterator over items found in `path` (normalized via |vim.fs.normalize()|).
 ---
 --- Example:
 ---
 --- ```lua
---- local it, err = vim.fs.dir(path)
----
---- if err then
----   -- Failed to scan the root directory
---- end
----
---- for name, type, err in it do
+--- for name, type, err in vim.fs.dir(path, { err = true }) do
 ---   if err then
----     -- Failed to scan a child directory
+---     -- Failed to scan directory {name} (may be the root {path} itself).
 ---   end
 --- end
 --- ```
@@ -209,29 +206,36 @@ end
 ---@since 10
 ---@param path (string) Directory to iterate over, normalized via |vim.fs.normalize()|.
 ---@param opts? vim.fs.dir.Opts Optional keyword arguments:
----@return fun(): string?, string?, string? # Iterator over items in {path}. Each iteration yields three values: name, type, err.
+---@return fun(): string?, string?, string? # Iterator over items in {path}, yielding (name, type, err):
 ---        - name: Basename of the item relative to {path}.
 ---        - type: One of: "file", "directory", "link", "fifo", "socket", "char", "block", "unknown".
----        - err: Error string, or nil.
----@return string? err Error encountered while scanning the base directory
+---        - err: Error string, or nil. Only if `opts.err=true`. If the root {path} itself could not
+---          be scanned, yields a single (name, nil, err) item.
 function M.dir(path, opts)
   opts = opts or {}
 
   vim.validate('path', path, 'string')
   vim.validate('depth', opts.depth, 'number', true)
-  vim.validate('skip', opts.skip, 'function', true)
+  vim.validate('err', opts.err, 'boolean', true)
   vim.validate('follow', opts.follow, 'boolean', true)
+  vim.validate('skip', opts.skip, 'function', true)
 
   path = M.normalize(path)
 
   local rootfs, rooterr = uv.fs_scandir(path)
 
   if not rootfs then
-    local empty = function()
-      return nil
+    -- Root scan failed:
+    -- - If opts.err=false, behave as an empty listing (back-compat).
+    -- - If opts.err=true, surface yield a single (name, nil, err) result.
+    local done = not opts.err
+    return function()
+      if done then
+        return nil
+      end
+      done = true
+      return path, nil, rooterr
     end
-
-    return empty, rooterr
   end
 
   if not opts.depth or opts.depth == 1 then
@@ -241,7 +245,7 @@ function M.dir(path, opts)
   end
 
   --- @async
-  local it = coroutine.wrap(function()
+  return coroutine.wrap(function()
     local dirs = { { path, 1, rootfs } }
     while #dirs > 0 do
       --- @type string, integer, any
@@ -264,7 +268,7 @@ function M.dir(path, opts)
         then
           local fs_next, err = uv.fs_scandir(M.joinpath(path, f))
           if not fs_next then
-            err_scan = err
+            err_scan = opts.err and err or nil
           else
             dirs[#dirs + 1] = { f, level + 1, fs_next }
           end
@@ -273,8 +277,6 @@ function M.dir(path, opts)
       end
     end
   end)
-
-  return it, nil
 end
 
 --- @class vim.fs.find.Opts
@@ -338,8 +340,8 @@ end
 ---             The function should return `true` if the given item is considered a match.
 ---
 ---@param opts? vim.fs.find.Opts Optional keyword arguments:
----@return string[] matches # Normalized paths |vim.fs.normalize()| of all matching items.
----@return string[] errors # Errors collected while searching.
+---@return string[] # Normalized paths |vim.fs.normalize()| of all matching items.
+---@return string[] # Errors collected while searching.
 function M.find(names, opts)
   opts = opts or {}
   vim.validate('names', names, { 'string', 'table', 'function' })
@@ -374,17 +376,11 @@ function M.find(names, opts)
     if type(names) == 'function' then
       test = function(p)
         local t = {}
-        local it, base_err = M.dir(p)
-        if base_err ~= nil then
-          table.insert(errors, base_err)
-        end
-        for name, type, err in it do
-          local f = M.joinpath(p, name)
+        for name, type, err in M.dir(p, { err = true }) do
           if err ~= nil then
             table.insert(errors, err)
-          end
-          if (not opts.type or opts.type == type) and names(name, p) then
-            table.insert(t, f)
+          elseif (not opts.type or opts.type == type) and names(name, p) then
+            table.insert(t, M.joinpath(p, name))
           end
         end
         return t
@@ -392,7 +388,7 @@ function M.find(names, opts)
     else
       test = function(p)
         local t = {} --- @type string[]
-        local ok, aerr = uv.fs_access(p, 'R') -- Check if the directory itself is readable
+        local ok, aerr = uv.fs_access(p, 'R') -- Check if the root dir is readable.
         if not ok then
           table.insert(errors, aerr)
           return t
@@ -434,36 +430,33 @@ function M.find(names, opts)
         break
       end
 
-      local it, base_err = M.dir(dir)
-      if base_err ~= nil then
-        table.insert(errors, base_err)
-      end
-      for other, type_, err in it do
-        local f = M.joinpath(dir, other)
+      for other, type_, err in M.dir(dir, { err = true }) do
         if err ~= nil then
           table.insert(errors, err)
-        end
-        if type(names) == 'function' then
-          if (not opts.type or opts.type == type_) and names(other, dir) then
-            if add(f) then
-              return matches, errors
-            end
-          end
         else
-          for _, name in ipairs(names) do
-            if name == other and (not opts.type or opts.type == type_) then
+          local f = M.joinpath(dir, other)
+          if type(names) == 'function' then
+            if (not opts.type or opts.type == type_) and names(other, dir) then
               if add(f) then
                 return matches, errors
               end
             end
+          else
+            for _, name in ipairs(names) do
+              if name == other and (not opts.type or opts.type == type_) then
+                if add(f) then
+                  return matches, errors
+                end
+              end
+            end
           end
-        end
 
-        if
-          type_ == 'directory'
-          or (type_ == 'link' and opts.follow and (uv.fs_stat(f) or {}).type == 'directory')
-        then
-          dirs[#dirs + 1] = f
+          if
+            type_ == 'directory'
+            or (type_ == 'link' and opts.follow and (uv.fs_stat(f) or {}).type == 'directory')
+          then
+            dirs[#dirs + 1] = f
+          end
         end
       end
     end