UTop crashes (after Windows upgrade ?)

Ecosystem
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1

I am not an actual Windows user but I am trying to configure an opam/ocaml/utop environment under Windows 11.

I am experiencing the following : when starting utop in PowerShell, it immediately crashes with exit code -1073741819. When started in Emacs, it displays its welcome banner but crashes when evaluating a phrase.

This is with utop 2.17.0 on OCaml 5.4.1.

So I pulled the Win11 VM that I had used some months ago to create a similar environment (with OCaml 5.3.0 and utop 2.16.0), and which used to work, and now also crashes.

The standard ocaml REPL works fine.

Can anybody reproduce this on an up-to-date Windows 11 system ? That is 10.0.26100.0 and upgrade 25H2.

3

Doing ocamldebug utop.exe then run gives a Fatal error: exception Sys_error(“Invalid argument”). Not sure if this comes from utop or ocamldebug because ocamldebug stops there with exit code 2 (cannot get a backtrace).

4

I think you’re seeing utop does not show prompt in windows · Issue #513 · ocaml-community/utop · GitHub - opam pin add lwt 6.0.0 is the workaround.

5

Thank you so much. I search there for “crash” ; I would have thought to describe the problem as merely an absence of prompt (inter alia because in Emacs mode, we still have the utop[0]> prompt).