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Am I the only one who finds Python's "forwards" backtraces confusing compared to every other language I've used? I can't help but think at least part of this co

by o11c 2y ago

Am I the only one who finds Python's "forwards" backtraces confusing compared to every other language I've used? I can't help but think at least part of this confusion is because of that. That said: * Would printing the trace as a tree actually clarify anything? * Good code almost always minimizes the amount of code in an exception handler. * `raise_exception()` is generally bad practice; consider `raise get_exception()` if you need something complicated (among others, this allows choice of `from`) * `raise ... from None` is useful since it's often the most recent stacktrace that's actually relevant. * `raise ... from e` likely implies that it is the older stacktrace that's most relevant; ideally this would just be a single annotation on a particular frame "exception was replaced here".

silenced_trope 2y ago
yes - I'm currently at a new job where I work on a python back-end, but there's also java/kotlin microservices, and I do front-end web with typescript or mobile with java/kotlin python is the only one doing this weird crap
vanschelven 2y ago
You're probably not the only one, but as a Python developer of 20 years I can assure you that the confusion _for me_ is not caused by the order of the Stacktrace itself, but specifically by the way chained exceptions are shown. `raise_exception()` in the example is just to ensure a trivial example which still has a stacktrace in the handler (this is not uncommon in reality, though in reality the called function is not typically called with the goal of triggering yet another example)
EdwardDiego 2y ago
TIL `raise from` especially the `raise from None`, yeesh
Sohcahtoa82 2y ago
> * Would printing the trace as a tree actually clarify anything? Could you give an example of what this tree would look like? A stack is entirely linear. I've never had a problem with Python's stack traces. Certainly better than Java, where the paradigms rely on a ridiculous amount of introspection, reflection, and abstraction, so your stack traces end up being a hundred lines long, with half of them being ".invoke()".

by o11c 2y ago

silenced_trope 2y ago

yes - I'm currently at a new job where I work on a python back-end, but there's also java/kotlin microservices, and I do front-end web with typescript or mobile with java/kotlin python is the only one doing this weird crap

vanschelven 2y ago

You're probably not the only one, but as a Python developer of 20 years I can assure you that the confusion _for me_ is not caused by the order of the Stacktrace itself, but specifically by the way chained exceptions are shown. `raise_exception()` in the example is just to ensure a trivial example which still has a stacktrace in the handler (this is not uncommon in reality, though in reality the called function is not typically called with the goal of triggering yet another example)

EdwardDiego 2y ago

TIL `raise from` especially the `raise from None`, yeesh

Sohcahtoa82 2y ago

> * Would printing the trace as a tree actually clarify anything? Could you give an example of what this tree would look like? A stack is entirely linear. I've never had a problem with Python's stack traces. Certainly better than Java, where the paradigms rely on a ridiculous amount of introspection, reflection, and abstraction, so your stack traces end up being a hundred lines long, with half of them being ".invoke()".