ExceptionDictTransformer hides ExceptionGroup sub exceptions

[brendanmaguire]

structlog version 24.4.0

The ExceptionDictTransformer hides the underlying ExceptionGroup#exceptions values.

For example, the following ExceptionGroup:

ExceptionGroup("some errors", [ValueError("wrong value"), TypeError("wrong type")])

will be returned as:

[{'exc_type': 'ExceptionGroup', 'exc_value': 'some errors (2 sub-exceptions)', 'syntax_error': None, 'is_cause': False, 'frames': []}]

I would have expected it to recursively iterate through the sub exceptions and add them as a normal top level exception would be transformed.

Maybe I'm missing something here and there is a built in transformer for this?

[sscherfke]

Here is a minimal example:

import asyncio
import structlog


structlog.configure(
    processors=[
        structlog.processors.dict_tracebacks,
        structlog.processors.JSONRenderer(),
    ],
)
log = structlog.get_logger()


async def task(i: int) -> None:
    raise ValueError(i)
    await asyncio.sleep(1)


async def main() -> None:
    async with asyncio.TaskGroup() as tg:
        tg.create_task(task(0))
        tg.create_task(task(1))


try:
    asyncio.run(main())
except Exception as e:
    log.exception("onoes", exc_info=e)

The Rich traceback of the ConsoleRenderer looks similar though, so the ExceptionDictTransformer behaves "as expected".

I suggest to wait until Textualize/rich#1859 is done and than steal their code as we did before. ;-)