Handling files which already exist in the subdirectory

lua/oil/adapters/files.lua

@@ -331,6 +331,15 @@ local function list_windows_drives(url, column_defs, cb)
   end
 end
 
+---@param url string
+M.file_exists = function(url)
+  local _, path = util.parse_url(url)
+  assert(path)
+  local dir = fs.posix_to_os_path(path)
+
+  return fs.file_exists(dir)
+end
+
 ---@param url string
 ---@param column_defs string[]
 ---@param cb fun(err?: string, entries?: oil.InternalEntry[], fetch_more?: fun())

lua/oil/fs.lua

@@ -160,6 +160,12 @@ M.mkdirp = function(dir, mode)
   end
 end
 
+--- @param path string
+--- @return boolean
+M.file_exists = function(path)
+  return uv.fs_stat(path) ~= nil
+end
+
 ---@param dir string
 ---@param cb fun(err: nil|string, entries: nil|{type: oil.EntryType, name: string})
 M.listdir = function(dir, cb)

lua/oil/init.lua

@@ -17,6 +17,7 @@ local M = {}
 ---@class (exact) oil.Adapter
 ---@field name string The unique name of the adapter (this will be set automatically)
 ---@field list fun(path: string, column_defs: string[], cb: fun(err?: string, entries?: oil.InternalEntry[], fetch_more?: fun())) Async function to list a directory.
+---@field file_exists fun(path: string) Returns true if the file at path exists
 ---@field is_modifiable fun(bufnr: integer): boolean Return true if this directory is modifiable (allows for directories with read-only permissions).
 ---@field get_column fun(name: string): nil|oil.ColumnDefinition If the adapter has any adapter-specific columns, return them when fetched by name.
 ---@field get_parent? fun(bufname: string): string Get the parent url of the given buffer

lua/oil/mutator/parser.lua

@@ -186,8 +186,31 @@ M.parse = function(bufnr)
       -- mac and windows use case-insensitive filesystems
       name = name:lower()
     end
+    local has_subdir = string.find(name, fs.sep)
+    local subdir_name = has_subdir
+        and string.match(name, string.format("([^%s]+)%s", fs.sep, fs.sep))
+      or nil
     if seen_names[name] then
       table.insert(errors, { message = "Duplicate filename", lnum = i - 1, end_lnum = i, col = 0 })
+    elseif has_subdir and adapter.file_exists(parent_url .. name) then
+      table.insert(
+        errors,
+        { message = "Duplicate file in nested path", lnum = i - 1, end_lnum = i, col = 0 }
+      )
+    elseif
+      has_subdir
+      and seen_names[subdir_name]
+      and not adapter.file_exists(parent_url .. subdir_name)
+    then
+      table.insert(errors, {
+        message = "Cannot move a file to a directory which has been renamed in the same action",
+        lnum = i - 1,
+        end_lnum = i,
+        col = 0,
+      })
+    elseif has_subdir then
+      seen_names[subdir_name] = true
+      seen_names[name] = true
     else
       seen_names[name] = true
     end
@@ -216,6 +239,11 @@ M.parse = function(bufnr)
         err_message = "No filename found"
       elseif not entry then
         err_message = "Could not find existing entry (was the ID changed?)"
+      elseif
+        adapter.name ~= "files"
+        and (parsed_entry.name:match("/") or parsed_entry.name:match(fs.sep))
+      then
+        err_message = "Filename cannot contain path separator"
       end
       if err_message then
         table.insert(errors, {