[Python-Dev] this is what happens if you freeze all the modules required for startup

[Ezio Melotti]

Hi,

On Thu, Apr 17, 2014 at 9:09 PM, Brett Cannon <bcannon at gmail.com> wrote:
>
>
> On Thu Apr 17 2014 at 1:34:23 PM, Jurko Gospodnetić
> <jurko.gospodnetic at pke.hr> wrote:
>>
>>    Hi.
>>
>> On 14.4.2014. 23:51, Brett Cannon wrote:
>> > Now the question is whether the maintenance cost of having to rebuild
>> > Python for a select number of stdlib modules is enough to warrant
>> > putting in the effort to make this work.
>>
>>    I would really love to have better startup times in production, but I
>> would also really hate to lose the ability to hack around in stdlib
>> sources during development just to get better startup performance.
>>
>>    In general, what I really like about using Python for software
>> development is the ability to open any stdlib file and easily go poking
>> around using stuff like 'import pdb;pdb.set_trace()' or simple print
>> statements. Researching mysterious behaviour is generally much much
>> MUCH! easier (read: takes less hours/days/weeks) if it ends up leading
>> into a stdlib Python module than if it takes you down into the bowels of
>> some C module (think zipimport.c *grin*). Not to mention the effect that
>> being able to quickly resolve a mystery by hacking on some Python
>> internals leaves you feeling very satisfied, while having to entrench
>> yourself in those internals for a long time just to find out you've made
>> something foolish on your end leaves you feeling exhausted at best.
>
>
> Freezing modules does not affect the ability to use gdb. And as long as you
> set the appropriate __file__ values then tracebacks will contain even the
> file line and location.
>

Will the tracebacks only contain the line number or the line of code too?

I've seen tracebacks involving importlib,_bootstrap that didn't
include the code, and I'm wondering if we will get something similar
for all the other modules you are freezing:

Traceback (most recent call last):
  File "/tmp/foo.py", line 7, in <module>
    import email
  File "<frozen importlib._bootstrap>", line 1561, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1519, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1473, in _find_module
  File "<frozen importlib._bootstrap>", line 1308, in find_module
  File "<frozen importlib._bootstrap>", line 1284, in _get_loader
  File "<frozen importlib._bootstrap>", line 1273, in _path_importer_cache
  File "<frozen importlib._bootstrap>", line 1254, in _path_hooks
TypeError: 'NoneType' object is not iterable

Best Regards,
Ezio Melotti



> -Brett
>
> _______________________________________________
> Python-Dev mailing list
> Python-Dev at python.org
> https://mail.python.org/mailman/listinfo/python-dev
> Unsubscribe:
> https://mail.python.org/mailman/options/python-dev/ezio.melotti%40gmail.com
>