`dune utop --watch` Appears to be broken

abhillman commented 1 year ago

Expected Behavior

If a file that has been loaded by utop has been changed (e.g. a local library), the source will be re-built and the latest version (if compilation is successful) will be available to utop.

Actual Behavior

--watch appears to do nothing

Reproduction

Simply run dune init project newproj and create a library with some function. From there, run dune utop and note that the function works; then modify the source for the function, and note that the old version is used by utop. By contrast, note that dune build --watch appears to work.

Specifications

Version of dune (output of dune --version):
```
$ dune --version
3.6.1
```

Version of ocaml (output of ocamlc --version)

$ ocaml --version
The OCaml toplevel, version 4.14.0

Operating system (distribution and version):

ahillman@mbp ~ % uname -a
Darwin mbp.local 22.1.0 Darwin Kernel Version 22.1.0: Tue Sep 27 22:07:43 PDT 2022; root:xnu-8792.41.6~5/RELEASE_ARM64_T8103 arm64

abhillman commented 1 year ago

Screenshot of the man page for dune-utop that mentions --watch:

abhillman commented 1 year ago

One workaround I just discovered, which I haven't quite seen documented before:

$ utop
# use_output "dune top";;

Then in a separate window, edit a file and then run dune build; then go back to utop and write # use_output "dune top";; again.

Seems to me could be bundled into a little method that could be stored in a config file or something like that.

Alizter commented 1 year ago

@rgrinberg @emillon We don't support the watch flag for dune ocaml utop is that correct?

rgrinberg commented 1 year ago

Not yet. It would require a little more design to spec how this would work.

ocaml / dune