`cmdliner install tool-support` bug on Windows when given a unix style path

[dbuenzli]

From the CI of js_of_ocaml ocsigen/js_of_ocaml#2140

#=== ERROR while compiling js_of_ocaml-compiler.dev ===========================#
# context     2.5.0 | win32/x86_64 | ocaml-base-compiler.5.4.0 | pinned(git+file://D:/a/js_of_ocaml/js_of_ocaml#HEAD#99e8d8f2a47bcf77ae3f37036dbde7dce7bf0443)
# path        D:\a\js_of_ocaml\js_of_ocaml\_opam\.opam-switch\build\js_of_ocaml-compiler.dev
# command     D:\a\js_of_ocaml\js_of_ocaml\_opam\bin\cmdliner.exe install tool-support --update-opam-install=js_of_ocaml-compiler.install _build/install/default/bin/js_of_ocaml.exe _build/cmdliner-install
# exit-code   123
# env-file    C:\.opam\log\js_of_ocaml-compiler-8388-37235b.env
# output-file C:\.opam\log\js_of_ocaml-compiler-8388-37235b.out
### output ###
# Creating directory _build/cmdliner-install\share\man\man1
# Writing _build/cmdliner-install\share\man\man1\_build/install/default/bin/js_of_ocaml.1
# _build/cmdliner-install\share\man\man1\_build/install/default/bin/js_of_ocaml.1: No such file or directory

I suspect that executable name split here is not performed correctly. Something must be wrong with the split_toolname function namely. Remains to see but I suspect Filename.basename gets confused because of the mixed / and \ path ?

[dbuenzli]

Remains to see but I suspect Filename.basename gets confused because of the mixed / and \ path ?

There is no mixed path I think it's just that the opam instructions use /, that's what the cmdliner the tool gets. But since the cmdliner tool is compiled on Windows Filename.basename uses this is_dirsep, so the whole path is the basename.

The workaround for now is to use PATH:NAME syntax in the install instructions.