ffi: 'void' as parameter type triggers internal assertion

Version

26.1.0

Platform

Subsystem

ffi

What steps will reproduce the bug?

const lib = new ffi.DynamicLibrary(null);
lib.getFunction('f', { parameters: ['void'] });

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

Whenever 'void' is provided in a parameters list.

What is the expected behavior? Why is that the expected behavior?

Unclear; the native ToFFIArgument appears to accept void arguments and just pass them as a pointer to 0, although I'm not sure how useful this behaviour is.

Either way, 'void' should either be accepted in a parameters list, or throw a validation error gracefully.

What do you see instead?

Uncaught:
Error [ERR_INTERNAL_ASSERTION]: FFI: shared-buffer type table missing entry for parameter type "void"
This is caused by either a bug in Node.js or incorrect usage of Node.js internals.
Please open an issue with this stack trace at https://github.com/nodejs/node/issues

    at wrapWithSharedBuffer (node:internal/ffi-shared-buffer:252:13)
    at DynamicLibrary.getFunction (node:internal/ffi-shared-buffer:570:10) {
  code: 'ERR_INTERNAL_ASSERTION'

Additional information

cc: @nodejs/ffi

@Renegade334

Hi @Renegade334, I'd like to work on a fix for this.

The native layer accepts void and passes it as a 0x0 pointer — which seems risky since a foreign function dereferencing that null pointer would segfault the whole process. That pushes me toward early validation with ERR_INVALID_ARG_VALUE.
But I'm not sure if there's a valid use case for void parameters I'm missing. What's the intended direction — validation error, or officially support it with defined behavior?

I agree: there is no reason to have void in parameters.
Given the way the code is structured, we can do this in the native layers, as both shared buffer and standard path call GetFunction and GetFunctions.

@ShogunPanda

I've opened a PR for this: #63504. Thanks for the confirmation and analysis @KaloudasDev and @ShogunPanda

ffi: validate 'void' as parameter type in getFunction and getFunctions

Thanks! Yeah, rejecting void early with a proper validation error felt much better than hitting an internal assertion.

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ffi: `'void'` as parameter type triggers internal assertion #63461

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What steps will reproduce the bug?

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

What is the expected behavior? Why is that the expected behavior?

What do you see instead?

Additional information

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ffi: 'void' as parameter type triggers internal assertion #63461

Description

Version

Platform

Subsystem

What steps will reproduce the bug?

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

What is the expected behavior? Why is that the expected behavior?

What do you see instead?

Additional information

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Anshikakalpana commented on May 22, 2026

ShogunPanda commented on May 23, 2026

Anshikakalpana commented on May 23, 2026

Anshikakalpana commented on May 27, 2026

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ffi: `'void'` as parameter type triggers internal assertion #63461