'SystemError: Type does not define the tp_name field' when an unhandled exception is thrown in an async function

[WhiteAbeLincoln]

componentize-py version: 0.18.0
reproduction: https://github.com/WhiteAbeLincoln/tp_name_reproduction

I'm noticing this error if an exception is raised from within an async function. It did not occur under 0.17.2.
The error raised is:

(nix:nix-shell-env) bash-5.3$ ./run.sh
Building wasm component...
warning: site-packages directory not found under /Users/abe/Projects/tp_name_reproduction/test/.venv/lib
Component built successfully
Executing wasm component...
error: Type does not define the tp_name field.
Traceback (most recent call last):
  File "/python/asyncio/runners.py", line 204, in run
  File "/python/asyncio/runners.py", line 127, in run
  File "/python/asyncio/base_events.py", line 719, in run_until_complete
  File "/0/test/__init__.py", line 13, in maybe_crash
Exception: Intentional exception to test cleanup

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/0/test/__init__.py", line 26, in run
  File "/python/asyncio/runners.py", line 203, in run
  File "/python/asyncio/runners.py", line 63, in __exit__
SystemError: Type does not define the tp_name field.

This causes the wasmtime cli to never exit. I'm not sure if that's by design on their part because my custom embedding
crashed after running into this error.

The reproduction is very simple - just throw an error within an async function which is running using asyncio.run.

I got an extended backtrace from the embedding which seems to point at an error when
deallocating the exception, but I don't know whether that's the root cause:

Exception in workflow_main: Type does not define the tp_name field.
Traceback (most recent call last):
  File "/1/m2i_workflow_sdk/entry.py", line 105, in main
  File "/python/asyncio/runners.py", line 127, in run
  File "/python/asyncio/base_events.py", line 719, in run_until_complete
  File "/0/tcp.py", line 60, in workflow_main
Exception: Intentional exception to test cleanup
During handling of the above exception, another exception occurred:
Traceback (most recent call last):

File "/1/m2i_workflow_sdk/entry.py", line 104, in main

File "/python/asyncio/runners.py", line 63, in exit

SystemError: Type does not define the tp_name field.
Error: workflow should complete
Caused by:

0: failed to run wasm module: error while executing at wasm backtrace:

0: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

1: 0xe4114d - Py_DECREF_MORTAL

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/internal/pycore_object.h:482:9

- PyStackRef_XCLOSE

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/internal/pycore_stackref.h:660:9

- frame_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/frameobject.c:1937:13

2: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

3: 0x1034815 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- Py_XDECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:512:9

- tb_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Python/traceback.c:240:5

4: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

5: 0x10347e0 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- Py_XDECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:512:9

- tb_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Python/traceback.c:239:5

6: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

7: 0xe2ac6a - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- BaseException_clear

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:139:5

8: 0xe2ebac - BaseException_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:153:11

9: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

10: 0xe2ace2 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- BaseException_clear

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:141:5

11: 0xe2ebac - BaseException_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:153:11

12: 0xea885a - subtype_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/typeobject.c:2708:5

13: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

14: 0xe7e6d8 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- _Py_DecRef

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:354:5

15:  0x13f6b - !<wasm function 303>

16: 0xc61202 - libcomponentize_py_runtime.so!pyo3::internal::state::register_decref::h10509524002982b7

17: 0xc37999 - libcomponentize_py_runtime.so!componentize-py#Dispatch

18: 0x2794cca - libcomponentize_py_bindings.so!m2i:workflows/workflow@0.1.0#main-export

1: error while executing at wasm backtrace:

0: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

1: 0xe4114d - Py_DECREF_MORTAL

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/internal/pycore_object.h:482:9

- PyStackRef_XCLOSE

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/internal/pycore_stackref.h:660:9

- frame_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/frameobject.c:1937:13

2: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

3: 0x1034815 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- Py_XDECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:512:9

- tb_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Python/traceback.c:240:5

4: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

5: 0x10347e0 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- Py_XDECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:512:9

- tb_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Python/traceback.c:239:5

6: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

7: 0xe2ac6a - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- BaseException_clear

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:139:5

8: 0xe2ebac - BaseException_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:153:11

9: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

10: 0xe2ace2 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- BaseException_clear

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:141:5

11: 0xe2ebac - BaseException_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/exceptions.c:153:11

12: 0xea885a - subtype_dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/typeobject.c:2708:5

13: 0xe7e5c5 - _Py_Dealloc

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:3072:5

14: 0xe7e6d8 - Py_DECREF

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Include/refcount.h:419:9

- _Py_DecRef

at /home/runner/work/componentize-py/componentize-py/cpython/builddir/wasi/../../Objects/object.c:354:5

15:  0x13f6b - !<wasm function 303>

16: 0xc61202 - libcomponentize_py_runtime.so!pyo3::internal::state::register_decref::h10509524002982b7

17: 0xc37999 - libcomponentize_py_runtime.so!componentize-py#Dispatch

18: 0x2794cca - libcomponentize_py_bindings.so!m2i:workflows/workflow@0.1.0#main-export

2: wasm trap: uninitialized element

[WhiteAbeLincoln]

Note that the error only occurs when using asyncio.run or with asyncio.Runner(). Calling run_until_complete directly on the event loop object does not crash.

[dicej]

Hi @WhiteAbeLincoln. Thanks for reporting this!

It looks like there are two bugs here: The tp_name field SystemError and the hang on sys.exit(1). As you noted, neither occurs with componentize-py 0.17.2, and both occur on 0.18.0. Interestingly, only the sys.exit(1) hang happens on 0.19.0 (due to be released shortly) -- not the SystemError. So whatever the SystemError was caused by seems to be fixed in 0.19.0; I'll dig into the sys.exit(1) issue.

[dicej]

Indeed, sys.exit(1) hangs regardless of whether exceptions are thrown or asyncio is used.

[dicej]

Oh, I think this is actually a known issue with WASI-SDK 26 and 27: WebAssembly/wasi-libc#617. I'll try upgrading to 28 and see if that fixes it.

[dicej]

I almost succeeded in updating to WASI-SDK 28, but then hit WebAssembly/wasi-libc#640. Once that's addressed, I'll be able to finish the update and fix the sys.exit hang. Meanwhile, I recommend avoiding sys.exit if you can (i.e. return normally from wasi:cli/run#run if possible).

[WhiteAbeLincoln]

Awesome, thank you for the quick response. Luckily the sys.exit call is only used in that reproduction. The actual code I'm working on uses run_until_complete so I've been able to avoid this error. I just ran into the bug as I was making some changes that ended up being unnecessary.