Not fully linked vm.Module throws errors from C++ when instantiated

[TimothyGu]

Executing

const neverLinked = new vm.Module('import "nonexistent";');
// Note: `await` intentionally omitted as the returned promise will never resolve.
neverLinked.link(() => new Promise(() => {}));

const main = new vm.Module('import "neverLinked";');
await main.link(() => neverLinked);
main.instantiate();

with --experimental-vm-modules throws

internal/vm/Module.js:170
    wrap.instantiate();
         ^
Error: linking error, dependency promises must be resolved on instantiate
    at Module.instantiate (internal/vm/Module.js:170:10)

which does not have the error code that is present on all other errors thrown by instantiate(). In comparison,

new vm.Module('').instantiate();

throws an error with a proper error code:

Error [ERR_VM_MODULE_NOT_LINKED]: Module must be linked before it can be instantiated

---

The thrown error comes from

node/lib/internal/vm/Module.js

Line 170 in 9974d6a

wrap.instantiate();

which due to restrictions on how V8's C++ API operates makes it inconvenient to add the error code. The way to fix this would be to wrap a try-catch block around

node/lib/internal/vm/Module.js

Line 170 in 9974d6a

wrap.instantiate();

to throw a proper errors.Error. The error message can be hard-coded as Linked dependencies must all be linked before instantiation, since this should be the only possible error thrown from this line.

---

See also #18106.

[ryzokuken]

@TimothyGu what's the status on this? Did you proceed with it?

[TimothyGu]

@ryzokuken No… Unassigning myself.

/cc @devsnek

[joyeecheung]

There is now node_errors.h so we could also throw the error with a hard-coded message from the C++ side instead of using a try-catch hack.

[jasnell]

Ping @TimothyGu ... does this need to remain open?

[TimothyGu]

Yes. The error is the same as the OP, though the script is now

// test.js
const neverLinked = new vm.SourceTextModule('import "nonexistent";');
// Note: `await` intentionally omitted as the returned promise will never resolve.
neverLinked.link(() => new Promise(() => {}));

const main = new vm.SourceTextModule('import "neverLinked";');
await main.link(() => neverLinked);
main.instantiate();

node --experimental-vm-modules test.js

[marco-ippolito]

@joyeecheung I think this issue can be closed since the vm.Module API has been changed

[legendecas]

Fixed by #37598