Default to showing a traceback in reticulate

[falexwolf]

I'm running a script remotely and the only error message I get is this.

$ Rscript test-docs/r-quickstart.R
→ connected lamindb: testuser1/test-docs
→ created Transform('tCHiOO2SZuHZ0000'), started new Run('UwCb0kAm...') at [20](https://github.com/laminlabs/laminr/actions/runs/14087099520/job/39453936522#step:13:21)25-03-27 07:21:48 UTC
Error in py_call_impl(callable, call_args$unnamed, call_args$named) : 
  TypeError: unsupported operand type(s) for -: 'set' and 'dict'
Run `reticulate::py_last_error()` for details.
Calls: <Anonymous> ... unwrap_args_and_call -> do.call -> <Anonymous> -> py_call_impl
Execution halted
Error: Process compl

I can't debug based on it and so I have to manually add this:

library(reticulate)
options(reticulate.traceback = TRUE)

Should we have this as the default behavior? It'd make it faster to debug; in particular if inexperienced users would report something.

[falexwolf]

Turns out the above doesn't have the desired effect and I still see no traceback.

Trying what seems truly cumbersome when working with a script:

ln$track()  # track your run of a notebook or script
reticulate::py_last_error()
artifact <- ln$Artifact$using("laminlabs/cellxgene")$get("7dVluLROpalzEh8m")  # https://lamin.ai/laminlabs/cellxgene/artifact/7dVluLROpalzEh8m
reticulate::py_last_error()
adata <- artifact$load()  # load the artifact into memory or sync to cache via filepath <- artifact$cache()
reticulate::py_last_error()

Which leads to printing NULL:

→ connected lamindb: testuser1/test-docs
→ created Transform('HmGDFThda10T0000'), started new Run('9uFnXJig...') at [20](https://github.com/laminlabs/laminr/actions/runs/14101230936/job/39497702865#step:13:21)25-03-27 07:41:41 UTC
NULL
Error in py_call_impl(callable, call_args$unnamed, call_args$named) : 
  TypeError: unsupported operand type(s) for -: 'set' and 'dict'
Run `reticulate::py_last_error()` for details.
Calls: <Anonymous> ... unwrap_args_and_call -> do.call -> <Anonymous> -> py_call_impl
Execution halted

[lazappi]

I don't think we should mess around with a users options (and it doesn't seem to help here anyway). Did you find the problem? I think I've seen something like this before but I can't remember exactly why. Maybe from using reticulate::import("lamindb") instead of import_module("lamindb")?

[falexwolf]

Yes, I was able to issue correct trackbacks by wrapping everything via try / catch - like syntax

The process was very cumbersome and took a lot of time. I almost felt like debugging segfault bugs in C++ in 2009 😆

So, I still think that we can somehow manage to show the full trackback so that one doesn't have to rewrite the entire code to debug code

[falexwolf]

Happy to link my journey when I'm back home -- it's a sequence of commits in one of the PRs last week