[Python-Dev] Beta version of the new devguide

Brett Cannon brett at python.org
Mon Jan 24 19:38:45 CET 2011

On Mon, Jan 24, 2011 at 07:33, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Mon, Jan 24, 2011 at 9:29 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
>> On Mon, 24 Jan 2011 20:33:07 +1000
>> Nick Coghlan <ncoghlan at gmail.com> wrote:
>>> On Mon, Jan 24, 2011 at 6:22 AM, Brett Cannon <brett at python.org> wrote:
>>> >> In "Getting Set Up" it describes how to build a pydebug build. Is that
>>> >> really necessary for those who plan only to contribute by working on
>>> >> pure Python code?
>>> >>
>>> >
>>> > Yes, there is actually a laundry list of reasons even people only
>>> > working on the stdlib should use a pydebug build.
>>> And one big reason why I don't unless I have a specific need to check
>>> something with it - it makes the already quite long running time for
>>> the full test suite take even longer :)
>> Please try the -j option to regrtest.
> While I must admit I'm still not in the habit of running tests in
> parallel, that's a substantial speed improvement regardless of build
> type, so a non-debug build is still noticeably faster.
> release (with -j4): 2 min 25 sec (3 min wall clock time)
> pydebug (with -j4): 4 min 43 sec (10 min wall clock time)

If you thinks that's slow, trying running it under coverage single-threaded. =)

> Given that I typically *don't* need the extra info from a debug build
> to analyse problems and a full configure and rebuild cycle takes less
> time than a single pydebug test run, I'll happily stick with the much
> faster test execution that comes from using a release build.

I'm not going to drag on arguing this point, but there is more to
pydebug builds than some debug info when working in the C code. For
instance, pure Python code can still trigger problems indirectly in C
code which gets picked up by a pydebug. You also have ResourceWarnings
now which are almost exclusively triggered by pure Python code.

My point is there is more to a pydebug build than just direct
debugging support for C code. But if running the test suite w/o a
debug build is what it takes to get people to run the test suite I
will take that over not running it at all.

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