Optimization flag

[drjdn]

I recently updated to version 3.6.0 and dune was complaining about the flag "--opt=3". This makes sense as:

js_of_ocaml build-runtime --help

doesn't document the --opt=[NUM] option. Removing the option from dune fixes the issue. Anyways, I'm not sure this is a bug as perhaps "--opt=3" doesn't do anything in this case.

[chenyan2002]

I have the same question. --opt is in Cmd_arg.options, but not Cmd_arg.options_runtime_only. Is opt=3 enabled for building runtime anyway?

[hhugo]

I believe this issue needs to be fixed while addressing ocaml/dune#1613

[hhugo]

opt=3 would not do anything when building the runtime for separate compilation. That's why it's not included.
Starting with dune 3.0, jsoo flags handling will allow you to specify --opt=3 for js_of_ocaml compile only, as well as allowing to configure flags for the entire project (see ocaml/dune#5049)