[issue22374] Replace contextmanager example and improve explanation

Berker Peksag added the comment: The old tag() example has been replaced with a different example in https://github.com/python/cpython/commit/bde782bb594edffeabe978abeee2b7082ab9bc2a (bpo-33468) -- resolution: -> duplicate stage: patch review -> resolved status: open -> closed

[issue22374] Replace contextmanager example and improve explanation

cowlinator added the comment: I would like to second the improved explanation of contextlib.contextmanager, and additionally point out another problem: A very important piece of information is missing from the documentation: how to return data from the

[issue22374] Replace contextmanager example and improve explanation

Serhiy Storchaka added the comment: swap_attr() looks too general. I think something more concrete would be better. But the documentation already contain other examples for contextmanager. closing() is good example, and redirect_stdout() would be good example. -- nosy:

[issue22374] Replace contextmanager example and improve explanation

Berker Peksag added the comment: We also have swap_attr() and swap_item() helpers in Lib/test/support/__init__.py. I've used a simplified version of swap_attr() in my patch. Since this is basically a document improvement I removed Python 2.7 from the versions field. -- keywords:

[issue22374] Replace contextmanager example and improve explanation

Martin Panter added the comment: You should probably use try / finally in your context manager to always restore the attribute. Having said that, I recently wrote a similar context manager, and then later discovered there is already “unittest.mock.patch” and/or “unittest.mock.patch.object”

[issue22374] Replace contextmanager example and improve explanation

New submission from Terry J. Reedy: https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager The current html contextmanager example is 'not recommended' for actual use, because there are better ways to accomplish the same goal. To me, is also unsatifactory in that the