Stream: jco

Topic: _getGlobalCurrentTaskMeta compatiblity?

view this post on Zulip Scott Waye (Mar 23 2026 at 13:35):

I'm trying to repro https://github.com/dotnet/runtimelab/issues/3247 with the latest version of wasi/wit-bindgen/nativeaot-llvm etc, but I'm hitting this error at runtime

C:\github\dotnet-3247-repro>node --stack-size=8192 test-host.mjs
file:///C:/github/dotnet-3247-repro/dist/ThreadStaticRepro.js:2081
  const { taskID } = _getGlobalCurrentTaskMeta(componentIdx);
          ^

TypeError: Cannot destructure property 'taskID' of '_getGlobalCurrentTaskMeta(...)' as it is undefined.
    at _lowerImportBackwardsCompat (file:///C:/github/dotnet-3247-repro/dist/ThreadStaticRepro.js:2081:11)
    at wasm://wasm/81ba884a:wasm-function[9]:0x112
    at ThreadStaticRepro.wasm.environment_get_environment (wasm://wasm/ThreadStaticRepro.wasm-01be54de:wasm-function[7685]:0x32f681)
    at ThreadStaticRepro.wasm.__wasilibc_initialize_environ (wasm://wasm/ThreadStaticRepro.wasm-01be54de:wasm-function[7664]:0x32f0c5)
    at ThreadStaticRepro.wasm.__wasilibc_initialize_environ_eagerly (wasm://wasm/ThreadStaticRepro.wasm-01be54de:wasm-function[7665]:0x32f220)
    at ThreadStaticRepro.wasm.__wasm_call_ctors (wasm://wasm/ThreadStaticRepro.wasm-01be54de:wasm-function[32]:0x363a)
    at ThreadStaticRepro.wasm._initialize (wasm://wasm/ThreadStaticRepro.wasm-01be54de:wasm-function[33]:0x3680)
    at _initGenerator (file:///C:/github/dotnet-3247-repro/dist/ThreadStaticRepro.js:7752:36)
    at _initGenerator.next (<anonymous>)
    at runNext (file:///C:/github/dotnet-3247-repro/dist/ThreadStaticRepro.js:7808:32)

Node.js v24.14.0

Is this an incompatibility between versions of jco and something else, wasi libc?

view this post on Zulip Victor Adossi (Mar 23 2026 at 15:51):

Hey Scott I'm not sure, but if I could get the component I could take a look and try to track it down. What version of Jco are you using?

To me it just looks like backwards compat that that broke/isn't working properly... But I'm not sure why it would be happening -- in general it seems like somehow an export was entered without a current task, but I can't say much more other than that

view this post on Zulip Victor Adossi (Mar 23 2026 at 15:52):

Can I use this reproduction ?

view this post on Zulip Victor Adossi (Mar 23 2026 at 16:11):

When I try to run through the reproduction in that repo above, I get a similar error as the user in that thread, but going all the way back to Jco 1.14.0, believe it or not:

Calling operation-a...
  CRASH on operation-a: null function or function signature mismatch
  Stack: RuntimeError: null function or function signature mismatch
    at .tmpwfZReW.GcAllocInternal(MethodTable*, unsigned int, unsigned long, Thread*) (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[110]:0x33d6)
    at .tmpwfZReW.RhpGcAlloc (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[109]:0x32f9)
    at .tmpwfZReW.AllocateObject(void*, MethodTable*, unsigned int, unsigned long) (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[923]:0x39139)
    at .tmpwfZReW.RhpNewArray (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[925]:0x3929a)
    at .tmpwfZReW.S_P_CoreLib_Internal_Runtime_ThreadStatics__GetUninlinedThreadStaticBaseForTypeSlow (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[1825]:0x7e2e0)
    at .tmpwfZReW.S_P_CoreLib_Internal_Runtime_ThreadStatics__GetUninlinedThreadStaticBaseForType (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[1378]:0x5d47c)
    at .tmpwfZReW.S_P_CoreLib_Internal_Runtime_ThreadStatics__GetThreadStaticBaseForType (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[1060]:0x44f9c)
    at .tmpwfZReW.__GetThreadStaticBase_S_P_CoreLib_System_Threading_ManagedThreadId (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[861]:0x38aef)
    at .tmpwfZReW.S_P_CoreLib_System_Threading_Lock__EnterAndGetCurrentThreadId (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[1388]:0x5e28c)
    at .tmpwfZReW.S_P_CoreLib_System_Runtime_CompilerServices_ClassConstructorRunner_Cctor__GetCctor (wasm://wasm/.tmpwfZReW-009c7d96:wasm-function[1826]:0x7e514)

Fatal error. Invalid Program: attempted to call a UnmanagedCallersOnly method from managed code.
  Follow-up call also failed: unreachable

Is there something you did to get the error you're looking at above? Is there something about my environment that doesn't match what you're doing?

I'm assuming that this issue does actually exist so I updated to the latest version of Jco 1.17.4 (just released) and I don't even see that line (_getGlobalCurrentTaskMeta(...) in the output at all

view this post on Zulip Victor Adossi (Mar 23 2026 at 16:28):

So we do use that intrinsic (that's used for async tasks) but maybe I'm building the example repro incorrectly because I don't get that intrinsic generated when I run the component. If you could give me the component directly that would save some time, but AFAICT I followed the build instructions correctly and ran dotnet correctly.

It seems like when your export is attempting to call an import it's failing around here:

https://github.com/bytecodealliance/jco/blob/49d5decb480954b9e0888b8722ec5738b45fd475/crates/js-component-bindgen/src/intrinsics/p3/async_task.rs#L2214

But upon entering the export there should have been a task already set...

That particular intrinsic is used by EnterSymmetricSyncGuestCall (upstream this is called Trampoline::EnterSyncCall) which is relatively new (compared to the rest of the machinery) -- is that implemented on your side? That should get called beforehand, and it's the intrinsic (on the Jco side) that sets that global current task meta.

That said, this feels like it might likely be a regression in that I need to make sure that Jco keeps working whether that trampoline is actually there or not (like it has in the past, I think if you can get the component to run properly on a previous version of Jco -- I could not)

view this post on Zulip Scott Waye (Mar 23 2026 at 17:16):

ThreadStaticRepro.wasm
Using jco 1.16.1

view this post on Zulip Scott Waye (Mar 23 2026 at 17:17):

I will upgrade jco to the latest and see what happens. I have started with that repo, but using latest wit-bindgen and nativeaot-llvm compiler as componentize-dotnet is a little out of date

view this post on Zulip Scott Waye (Mar 23 2026 at 17:18):

WASI SDK 29

view this post on Zulip Scott Waye (Mar 23 2026 at 18:08):

let me start with something basic, how do I install the latest jco, should I build from source?

view this post on Zulip Scott Waye (Mar 23 2026 at 18:09):

cargo install jco doesn't seem to be what I want
C:\github\jco>npx

Entering npm script environment at location:
C:\github\jco
Type 'exit' or ^D when finished

Microsoft Windows [Version 10.0.26200.7840]
(c) Microsoft Corporation. All rights reserved.

C:\github\jco>^D

view this post on Zulip Scott Waye (Mar 23 2026 at 18:10):

and npm run build doesn't seem to find npx

view this post on Zulip Scott Waye (Mar 23 2026 at 18:10):

C:\github\jco>npm run build

> build
> cargo xtask build debug

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.12s
     Running `target\debug\xtask.exe build debug`
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.27s
Error: command not found: `npx`
error: process didn't exit successfully: `target\debug\xtask.exe build debug` (exit code: 1)

Last updated: Mar 23 2026 at 18:16 UTC