module: fix error message for not found

[JacksonTian]

When I written module path with a typo:

import {readdir} from 'fs/promisesxxx';

The error message tell me cannot find package 'fs'.

$ node test.js 
node:internal/modules/esm/resolve:853
  throw new ERR_MODULE_NOT_FOUND(packageName, fileURLToPath(base), null);
        ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'fs' imported from /PATH_TO_FILE/test.js
    at packageResolve (node:internal/modules/esm/resolve:853:9)
    at moduleResolve (node:internal/modules/esm/resolve:910:20)
    at defaultResolve (node:internal/modules/esm/resolve:1130:11)
    at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:396:12)
    at ModuleLoader.resolve (node:internal/modules/esm/loader:365:25)
    at ModuleLoader.getModuleJob (node:internal/modules/esm/loader:240:38)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:85:39)
    at link (node:internal/modules/esm/module_job:84:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}

Node.js v20.11.1

Actually the fs is a native module, the package should be a full name. This update try to fix it.

[nodejs-github-bot]

Review requested:

• @nodejs/loaders

[GeoffreyBooth]

What bug does this fix?

Please add a description explaining your intent with this PR and why it’s the best solution of alternatives you considered.

[JacksonTian]

@GeoffreyBooth Updated.

[aduh95]

Actually the fs is a native module, the package should be a full name. This update try to fix it.

node:fs is, but fs can be a userland module. If you run the following:

mkdir repro && cd repro
mkdir -p node_modules/fs
echo 'export let readdir' > node_modules/fs/promisesxxx.mjs
echo '{"name":"fs","exports":{"./promisesxxx":"./promisesxxx.mjs"}}' > node_modules/fs/package.json
node --input-type=module -e 'import {readdir} from "fs/promisesxxx"'
cd .. && rm -r repro

You can see that the import doesn't raise any error.

[aduh95]

I don't think this is correct, the missing package is fs, not fs/promisesx. What you could do is to add the complete specifier – either as Cannot find package 'fs' imported from … while trying to resolve 'fs/promisesx', or as an additional property on the error.

[avivkeller]

IMO for the end-users, Cannot find package 'fs' will not hint them that fs/promisesx is the not-found package/specifier.

But I'm not an expert on this, so IDK.

[guybedford]

+1 to the suggestion by @aduh95 as this giving more context.

For builtins, it might even be worth having a different error message, that is builtin specific:

Unable to import builtin module 'fs/promisesx'.

And if we're doing wishful thinking, would be amazing to see levenshtein distance searching:

Unable to import builtin module 'fs/promisesx', did you mean 'fs/promises'?.

Such suggestion error messages could in theory even apply to node_modules packages lookups and exports as well.

[avivkeller]

Suggestion error messages seem like a good idea to have in general :-)

[JacksonTian]

Actually the fs is a native module, the package should be a full name. This update try to fix it.

node:fs is, but fs can be a userland module. If you run the following:

mkdir repro && cd repro
mkdir -p node_modules/fs
echo 'export let readdir' > node_modules/fs/promisesxxx.mjs
echo '{"name":"fs","exports":{"./promisesxxx":"./promisesxxx.mjs"}}' > node_modules/fs/package.json
node --input-type=module -e 'import {readdir} from "fs/promisesxxx"'
cd .. && rm -r repro

You can see that the import doesn't raise any error.

The key point is should report the full package name in error message. It is not related to native module or user-land module.

[aduh95]

The key point is should report the full package name in error message. It is not related to native module or user-land module.

The full package name is 'fs', and that's already what's shown in the error message. If you want to add the full specifier, see my suggestion above.