Document types.CodeType.replace() changes about co_exceptiontable

[vstinner]

BPO	47236
Nosy	@gvanrossum, @vstinner

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2022-04-05.23:22:06.882>
labels = ['3.11', 'docs']
title = 'Document types.CodeType.replace() changes about co_exceptiontable'
updated_at = <Date 2022-04-05.23:23:47.642>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2022-04-05.23:23:47.642>
actor = 'gvanrossum'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2022-04-05.23:22:06.882>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 47236
keywords = []
message_count = 1.0
messages = ['416831']
nosy_count = 3.0
nosy_names = ['gvanrossum', 'vstinner', 'docs@python']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue47236'
versions = ['Python 3.11']

[vstinner]

It would be nice to document the bpo-40222 changes in What's New in Python 3.11 and in the CodeType documentation:

• https://docs.python.org/dev/library/types.html#types.CodeType
• https://docs.python.org/dev/whatsnew/3.11.html

Users of types.CodeType.replace(co_code=new_code) must now pass co_exceptiontable or exception handling will no longer work as expected. Callers are responsible to build co_exceptiontable.

Currently, the format of this table is documented at:
https://github.com/python/cpython/blob/main/Objects/exception_handling_notes.txt

There is no public function to encode this table, it's also the responsibility of the caller.

See also bpo-47185 "code.replace(co_code=new_code) no longer catch exceptions on Python 3.11" closed as "won't fix" for the background.