Breaks cygwin emacs

[ttamttam]

After a fresh installation of 32 bits cygwin (and emacs-w32 package), I checked that emacs was working as expected (see below) when started from a cygwin shell.

I then installed opam using the manual method explained here : https://fdopen.github.io/opam-repository-mingw/installation/.

After merlin, tuareg and utop were installed (without modifying emacs' configuration), emacs is still working fine.

I then tried to configure emacs like this:

opam install user-setup
opam user-setup install --editors=emacs

(Note: without the --editors option, emacs is not detected?)

From now on, emacs dired mode does no more work. The message from emacs is:

dired-insert-directory: Searching for program: No such file or directory, ls

If the following line is commented out, dired mode works again as expected:

(require 'opam-user-setup "~/.emacs.d/opam-user-setup.el")

Something in opam-user-setup.el is wrong in my configuration.

$ opam show user-setup
             package: user-setup
             version: 0.6
          repository: mingw
        upstream-url: https://github.com/OCamlPro/opam-user-setup/archive/0.6.tar.gz
       upstream-kind: http
   upstream-checksum: 223d53b4d6bd61b5f4fee9cad128573d
            homepage: https://github.com/AltGr/opam-user-setup
         bug-reports: https://github.com/AltGr/opam-user-setup/issues
            dev-repo: git+https://github.com/AltGr/opam-user-setup.git
             authors: Louis Gesbert <louis.gesbert@ocamlpro.com>
             license: ISC
                tags: org:ocamlpro, flags:plugin
             depends: ocamlfind & cmdliner & re
             depopts: tuareg | merlin | ocp-indent | ocp-index
   installed-version: 0.6 [4.03.0+mingw32c]
  available-versions: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6
         description: Helper for the configuration of editors for the use of OCaml tools

I'm not sure how to narrow down the problem?