Re: Read-only error

Am Tue, Jul 14, 2026 at 10:05:32AM -0400 schrieb Random832:

> The problem is that if Python wants to provide information
> that isn't provided in the error code from the operating
> system, it has to do a complex and potentially expensive
> root cause analysis on its own, checking for all the
> possible conditions that could have caused the error. Do you
> do this every time there is an error, or only when
> requested? having it be a subclass rather than a property
> makes 'only when requested' more difficult to design.

It could be

	try:
		provoke_PermissionError()
	except PermissionError as e:
		try:
			root_cause = e.do_root_cause_analysis_even_if_it_takes_some_effort(maybe_list_of_potential_causes_to_check)
		except:
			report_issue()
			raise e

		match root_cause:
			case FileReadOnlyError:
				raise MyFancyReadOnlyErrorOrSomeSuch(further_information)
			case_:
				raise e

so I'll pay the dividend only when I am (or my users are)
prepared to do so.

> And what if a secondary error is encounted while doing the
> analysis [e.g. you can't stat the file]?

Just like now:

	>>> try:
	...  1 / 0
	... except Exception:
	...  100 / 0
	...
	Traceback (most recent call last):
	  File "<stdin>", line 2, in <module>
	ZeroDivisionError: division by zero

	During handling of the above exception, another exception occurred:

	Traceback (most recent call last):
	  File "<stdin>", line 4, in <module>
	ZeroDivisionError: division by zero

Karsten
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