mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-24 11:44:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

bpo-41576: document BaseException in favor of bare except (GH-21917)

Browse source
This commit is contained in:
Thomas Grainger 2021-08-06 21:44:15 +01:00 • committed by GitHub
parent 0ffdced3b6
commit e9a6f1b78b
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 10 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

17
Doc/tutorial/errors.rst
View file

@ -147,10 +147,10 @@ For example, the following code will print B, C, D in that order::
Note that if the *except clauses* were reversed (with ``except B`` first), it
would have printed B, B, B --- the first matching *except clause* is triggered.
The last *except clause* may omit the exception name(s), to serve as a wildcard.
Use this with extreme caution, since it is easy to mask a real programming error
in this way! It can also be used to print an error message and then re-raise
the exception (allowing a caller to handle the exception as well)::
All exceptions inherit from :exc:`BaseException`, and so it can be used to serve
as a wildcard. Use this with extreme caution, since it is easy to mask a real
programming error in this way! It can also be used to print an error message and
then re-raise the exception (allowing a caller to handle the exception as well)::
import sys
@ -162,10 +162,13 @@ the exception (allowing a caller to handle the exception as well)::
print("OS error: {0}".format(err))
except ValueError:
print("Could not convert data to an integer.")
except:
print("Unexpected error:", sys.exc_info()[0])
except BaseException as err:
print(f"Unexpected {err=}, {type(err)=}")
raise
Alternatively the last except clause may omit the exception name(s), however the exception
value must then be retrieved from ``sys.exc_info()[1]``.
The :keyword:`try` ... :keyword:`except` statement has an optional *else
clause*, which, when present, must follow all *except clauses*. It is useful
for code that must be executed if the *try clause* does not raise an exception.
@ -493,5 +496,3 @@ used in a way that ensures they are always cleaned up promptly and correctly. ::
After the statement is executed, the file *f* is always closed, even if a
problem was encountered while processing the lines. Objects which, like files,
provide predefined clean-up actions will indicate this in their documentation.