[Unison-hackers] Need fix for chmod problem

[Dale R. Worley]

I've gotten stuck in a situation where I really need to suppress any
attempt by Unison to change the permissions of files.

(One of the directories is on an SMB share mounted on a Linux system.
chmod calls on that filesystem fail, and there is no "quiet" option to
prevent them from returning errors.)

I don't know ML, but Unison is really clean code, so I think I know what
needs to be done.  In props.ml at lines 166 et seq. is the function:

let set fspath path kind (fp, mask) =
  if mask <> 0 || kind <> `Update then
    Util.convertUnixErrorsToTransient
    "setting permissions"
      (fun () ->
        let abspath = Fspath.concatToString fspath path in
        debug
          (fun() ->
            Util.msg "Setting permissions for %s to %s (%s)\n"
              abspath (toString (fileperm2perm fp))
              (Printf.sprintf "%o/%o" fp mask));
        Unix.chmod abspath fp)

I think that the second line is incorrect, in that if mask is 0, but the
kind of operation is not Update (and specifically, if it is the creation
of a file), the code will still attempt to chmod the file.  Instead,
that 'if' clause should be:

  if mask <> 0 then

Do you developers agree with me?

Thanks, as this is a real problem here,

Dale