ppx rewriter - current file path as the cwd instead of the project root

[anentropic]

I made a ppx extension rewriter

It takes a string constant as an arg, representing a file path.

If I use a relative path like [%myppx "lib/myppx/data.json"] then I get a red underline in VS Code, with the error:

I/O error: lib/myppx/data.json: No such file or directory
ocamllsp

(this code would be in say lib/myproject/some.ml)

However I can compile and run my code via dune no problem.

VS Code project was opened from my project root.

So the issue seems to be that ocamllsp doesn't have the project root as the cwd ?

If I change the path to [%myppx "../myppx/data.json"] then ocamllsp is happy, but I can no longer build in dune. This implies ocamllsp is using the current file path as the cwd instead of the project root.

Is there a config setting I can use to fix this?

[anentropic]

I tried adding root to .vscode/settings.json:

    "ocaml.sandbox": {
        "kind": "opam",
        "switch": "${workspaceFolder:my-project}",
        "root": "/Users/anentropic/Documents/Dev/my-project-root"
    },

but it didn't help, even after closing and re-opening the IDE

[smorimoto]

The workspace might help with that: https://code.visualstudio.com/docs/editor/workspaces