Unable to use npm imports when BYONM is enabled

[redabacha]

Version: Deno 1.42.1

There are many times where I have one-off dependencies that are used in scripts that would not make sense to include as part of the main project package.json. However when BYONM is enabled, you are unable to use npm: imports anymore and will receive this error message like this if attempting to do so:

error: Could not find a matching package for '...' in '.../package.json'. You must specify this as a package.json dependency when the node_modules folder is not managed by Deno.

This is not the case for JSR and HTTPS imports which continue to work as normal which feels very inconsistent. Having NPM imports continue to function while BYONM is enabled would make mode 3 described in this issue a much more effective and realistic option.

[lucacasonato]

There are 3 possible solutions for this as a user:

1. add the npm specifier to deno.json or package.json and install into the node_modules.
2. run the tools script with --node-modules-dir=none. This will cause Deno to use the global resolver for this script, disabling BYONM entirely
3. install the package by running deno install with your script as an "entrypoint", which will cause it to install any packages that script depends on: deno install -e ./main.ts (this is not yet implemented, but will be before Deno 2.0.

[dsherret]

After #25399 , it will now be possible to put these jsr dependencies in the deno.json and run deno install. After that, the npm deps of the JSR dependencies will resolve. There's no way to make this work with other package managers without putting these missing dependencies in a package.json though.

Going to close this one because it's basically done other than #25411 which can be handled there.