[3.9] bpo-42669: Document that except rejects nested tuples (GH-23822)
#23870
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In Python 2, it was possible to use `except` with a nested tuple, and occasionally natural. For example, `zope.formlib.interfaces.InputErrors` is a tuple of several exception classes, and one might reasonably think to do something like this:
try:
self.getInputValue()
return True
except (InputErrors, SomethingElse):
return False
As of Python 3.0, this raises `TypeError: catching classes that do not inherit from BaseException is not allowed` instead: one must instead either break it up into multiple `except` clauses or flatten the tuple. However, the reference documentation was never updated to match this new restriction. Make it clear that the definition is no longer recursive.
Automerge-Triggered-By: GH:ericvsmith
(cherry picked from commit c95f8bc)
Co-authored-by: Colin Watson <cjwatson@debian.org>
|
@cjwatson: Status check is done, and it's a success ✅ . |
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In Python 2, it was possible to use
exceptwith a nested tuple, and occasionally natural. For example,zope.formlib.interfaces.InputErrorsis a tuple of several exception classes, and one might reasonably think to do something like this:As of Python 3.0, this raises
TypeError: catching classes that do not inherit from BaseException is not allowedinstead: one must instead either break it up into multipleexceptclauses or flatten the tuple. However, the reference documentation was never updated to match this new restriction. Make it clear that the definition is no longer recursive.Automerge-Triggered-By: GH:ericvsmith
(cherry picked from commit c95f8bc)
Co-authored-by: Colin Watson cjwatson@debian.org
https://bugs.python.org/issue42669