require throws, but require.resolve does not

[ljharb]

Version

16.15.0

Platform

Darwin computername.local 20.6.0 Darwin Kernel Version 20.6.0: Wed Jan 12 22:22:42 PST 2022; root:xnu-7195.141.19~2/RELEASE_X86_64 x86_64

Subsystem

node:readline/promises

What steps will reproduce the bug?

1. run node -pe "require.resolve('readline/promises2')" and node -pe "require('readline/promises2')". Observe that both throw.
2. run node -pe "require('node:readline/promises')". Observe that it throws "no such builtin module".
3. run node -pe "require.resolve('node:readline/promises')" or node -pe "require.resolve('node:readline/promises2'), and instead of throwing, both print the given specifier.

Modules that are not requireable must NEVER be require.resolveable; that's part of the contract of require.

How often does it reproduce? Is there a required condition?

No response

What is the expected behavior?

No response

What do you see instead?

See above.

Additional information

No response

[ljharb]

cc @nodejs/modules

[ljharb]

Note: this also seems to be the case in node 14, but not 18. (update: in resolve's tests, but see below; apparently it is broken in node 18)

[aduh95]

Note: this also seems to be the case in node 14, but not 18.

I'm able to reproduce on both v18.x and master:

$ node -pe 'require.resolve("node:readline/promises2")'
node:readline/promises2
$ out/Release/node -pe 'require.resolve("node:readline/promises2")'
node:readline/promises2
$ out/Release/node -pe 'require("node:readline/promises2")'       
node:internal/modules/cjs/loader:790
      throw new ERR_UNKNOWN_BUILTIN_MODULE(filename);
      ^

Error [ERR_UNKNOWN_BUILTIN_MODULE]: No such built-in module: node:readline/promises2
    at new NodeError (node:internal/errors:388:5)
    at Module._load (node:internal/modules/cjs/loader:790:13)
    at Module.require (node:internal/modules/cjs/loader:1008:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at [eval]:1:1
    at Script.runInThisContext (node:vm:129:12)
    at Object.runInThisContext (node:vm:305:38)
    at node:internal/process/execution:76:19
    at [eval]-wrapper:6:22
    at evalScript (node:internal/process/execution:75:60) {
  code: 'ERR_UNKNOWN_BUILTIN_MODULE'
}

Node.js v19.0.0-pre

[ljharb]

oh hm, thanks for confirming. the resolve tests didn't fail on node 18, oddly enough.

Either way, this feels like a sizable bug with the node: protocol. It would be ideal to get a fix for this landed and backported as far back as possible (14).