Suggest installing a supported ReScript version when the binary is not found

[Minnozz]

When depending on bs-platform@8.4.2:

• I'm not sure where "the directory null" comes from
• Maybe we could look for bs-platform in node_modules if rescript can't be found and suggest updating?

[cristianoc]

I think this is being done already.
CC @fhammerschmidt

[Minnozz]

If you mean #529, that fixes the "null" in the error message but still only looks inside node_modules/rescript and does nothing with node_modules/bs-platform.

Now that I think of it, maybe we could also detect when npm install is not run yet and suggest doing that?

[fhammerschmidt]

How about just rephrasing the message? Not sure If we really should check for bs-platform recursively just for the error message.

Something like:

Can't find ReScript binary in <working-directory>/node_modules/.bin or parent directories. Did you install it? It's required to use "rescript" > 9.1

[Minnozz]

Good idea 👍

[fhammerschmidt]

@cristianoc fine for you?

[cristianoc]

Note bs-platform is not supported.
That's also specified in the release notes.
So the title of this seems confusing.

[Minnozz]

@cristianoc How about this?

[cristianoc]

Sounds good. The only thing to check is that the message is compatible with the search strategy (which does not look into a single directory).