Issue 29235: Allow profile/cProfile to be used as context managers

The `enable` and `disable` methods on the profilers fit the description of a context manager very well. The following code:

    pr = cProfile.Profile()
    pr.enable()
    # ... do something ...
    pr.disable()
    pr.print_stats()

Would turn into something like this:

    with cProfile.Profile() as pr:
        # ... do something ...
    pr.print_stats()

The patch for this code would be trivial and backwards-compatible: simply add something like the following lines to the _lsprof.Profiler base class:

    def __enter__(self):
        self.enable()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.disable()

So this is my first time contributing to Python, but here's a (trivial) patch for this issue. Let me know what else is required to make this happen. I suspect unit tests and documentation updates?

> I suspect unit tests and documentation updates?

Yes. Code alone is not enough. It's better to have tests and documentation. Also, it's appreciated to sign the CLA: https://www.python.org/psf/contrib/contrib-form/. :-)

I've signed the agreement. I will do the necessary research to figure out how to do unit tests and documentation updates.

I should also mention that while maintaining API-compatibility with `profile` was a stated goal, it turns out that the pure-python profiler actually does not have the enable() and disable() methods that the context manager needs.

This looks like it's been dormant for a bit. I've posted a patch (with tests and docs) to https://github.com/python/cpython/pull/6808.

New changeset 2e01b75884892d5aabdaab658fbd17f7a7ccebaa by Brett Cannon (Scott Sanderson) in branch 'master':
bpo-29235: Make cProfile.Profile a context manager (GH-6808)
https://github.com/python/cpython/commit/2e01b75884892d5aabdaab658fbd17f7a7ccebaa

Please add a versionadded or versionchanged directive in the documentation (not sure what is more appropriate in this case) and an entry in What's New.

A news entry shouldn't consist of several paragraphs. This will be lost when news entries will be merged into a single NEWS file.

I've posted a patch to update the docs to https://github.com/python/cpython/pull/7331.

New changeset cebe80b59b7386db3cce904d280dab61d1037e7a by INADA Naoki (Scott Sanderson) in branch 'master':
bpo-29235: Update document for Profiler's context manager (GH-7331)
https://github.com/python/cpython/commit/cebe80b59b7386db3cce904d280dab61d1037e7a

Closing as these changes have been merged for a few months.

msg285538 mentions that the pure-Python profiler doesn't have `enable` and `disable`, which is already opened in issue 32017.

nosy: + cheryl.sabella
messages: + msg334514

resolution: fixed
stage: patch review -> resolved

messages: + msg318460
versions: + Python 3.8, - Python 3.7

messages: + msg285536
stage: needs patch -> test needed

stage: needs patch