ERROR Failed attempting to build your project with Dune

[bentxt]

npm create melange-app@latest

 ERROR

    Failed attempting to build your project with Dune
    The scaffolding process failed while running `opam exec -- dune build`.
    Dune is OCaml and ReasonML's build tool.
    Please try `cd`ing into the project directory created by
    `create-melange-app` and running the following commands:

    eval $(opam env)
    dune build
[...]
    `opam switch list`,
    `dune build`,
    `cat dune-project`, and `cat dune`

eval $(opam env)

dune build

ben@moonraker meli $ dune build
File "dune", line 32, characters 0-349:
32 | (rule
33 |   (alias webpack)
34 |    (targets (dir dist))
....
41 |               --entry ./output/src/App.mjs && cp ./public/index.html dist/index.html"))
42 |    (mode
43 |      (promote (until-clean))))
/bin/sh: ../../node_modules/.bin/webpack: No such file or directory

opam switch list

ben@moonraker meli 1 $ opam switch list
#   switch                                         compiler                    description
    /Users/ben/build/flow/flow                     ocaml-base-compiler.4.14.0  /Users/ben/build/flow/flow
    /Users/ben/hack/melange/melange-opam-template  ocaml-base-compiler.5.1.0   /Users/ben/hack/melange/melange-opam-template
->  /Users/ben/hack/melange/meli/meli              ocaml-base-compiler.5.1.1   /Users/ben/hack/melange/meli/meli
    /Users/ben/sources/nox/nox                     ocaml-base-compiler.5.0.0   /Users/ben/sources/nox/nox
    default                                        ocaml.5.1.1                 default

[NOTE] Current switch has been selected based on the current directory.
       The current global system switch is default.

dune build

ben@moonraker meli $ dune build
File "dune", line 32, characters 0-349:
32 | (rule
33 |   (alias webpack)
34 |    (targets (dir dist))
....
41 |               --entry ./output/src/App.mjs && cp ./public/index.html dist/index.html"))
42 |    (mode
43 |      (promote (until-clean))))
/bin/sh: ../../node_modules/.bin/webpack: No such file or directory

dune file

 $ perl -nle '/^;/ || print' dune

(dirs :standard \ node_modules)

(alias
  (name all)
  (deps
     (alias_rec webpack)))

(rule
  (alias webpack)
   (targets (dir dist))
   (deps
     (alias_rec meli)
     (:webpack ./webpack.config.js)
     (source_tree ./public))
   (action
    (system "../../node_modules/.bin/webpack --mode production \
              --entry ./output/src/App.mjs && cp ./public/index.html dist/index.html"))
   (mode
     (promote (until-clean))))

  (melange.emit
   (target output)
   (alias meli)
   (libraries app)
   (module_systems (es6 mjs)))

dune-project file

$ perl -nle '/^;/ || print' dune-project
(lang dune 3.14)

(using melange 0.1)

(using directory-targets 0.1)

(name meli)

(generate_opam_files true)

(source
 (github your-username/meli))

(authors "Your Name <your.email@gmail.com>")

(maintainers "Your Name <your.email@gmail.com>")

(license MIT)

(documentation https://github.com/your-username/meli)

(package
 (name meli)
 (synopsis "Enter a synopsis of your app here")
 (description "Enter a description of your app here")
 (allow_empty)
 (depends
  (dune (>= 3.14))
  (melange (>= 3.0.0-51))
  (ocaml (>= 5.1.1))
  opam-check-npm-deps
  ppx_deriving
  (reason (>= 3.11.0))
)
 (tags
  (reasonml, ocaml, melange)))

[dmmulroy]

By chance did you opt out of running npm install? Could you share the package.json that was generated?

[irfanns]

Hi, I got this issue too with both vite and webpack. Seems there's an issue with dune build getting to the node_modules/ subfolder in the project root, as the dune build seems to happen two folders upward of the created project?

Already ran npm install, npm i vite (for the vite project) and also npm i webpack (for the webpack project)

Thank you!

-- hi, after debugging locally, I think the problem was with opam switches. I have set the global opam switch to a top folder location and it seemed to have broke dune build. After deleting all local opam switches and trying again, it works now. Thanks!