After getting the resolved path from validateDocmapPath, Lstat the path
immediately before os.Open, then compare with f.Stat() after open using
os.SameFile. If the file was swapped between validation and open (e.g.,
replaced with a symlink pointing outside the repo), the inode comparison
catches it and returns an error.
Also changes defer f.Close() // nolint:errcheck to
defer func() { _ = f.Close() }() to follow the project convention of
explicit ignores over suppressor comments.
Addresses security bot finding (review 4812) against d6bab7a9.
Rodin
c76e7dcd2e