On 02/07/2020 07:33 AM, Serhiy Storchaka wrote:
07.02.20 16:28, Ram Rachum пише:
The idea is to add `raise as` syntax, that raises an exception while setting
the currently caught exception to be the cause. It'll look like this:
try:
1/0
except ZeroDivisionError:
raise as ValueError('Whatever')
What it does is a shorter version of this:
try:
1/0
except ZeroDivisionError as error:
raise ValueError('Whatever') from error
How does it differ from
try:
1/0
except ZeroDivisionError:
raise ValueError('Whatever')
Here's a diff:
$ diff no_from.py with_from.py
3,4c3,4
- ... except ZeroDivisionError:
- ... raise ValueError('Whatever')
---
+ ... except ZeroDivisionError as e:
+ ... raise ValueError('Whatever') from e
10c10
- During handling of the above exception, another exception occurred:
---
+ The above exception was the direct cause of the following exception:
To me the difference between "raise from" and "raise" is the implicit meaning:
- "During handling of ..." implies that the second exception should not have
occurred and there is a bug in the exception handling code
- "The above exception ..." implies that this code path is normal and extra
information is being supplied
Personally, my main use of "raise from" is "raise from None".
I'm -1 on the new syntax: to me it looks much more like a "raise ... from None".
--
~Ethan~
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