[Python-Dev] #12982: Should -O be required to *read* .pyo files?

[Ethan Furman]

Steven D'Aprano wrote:
> On Wed, Jun 13, 2012 at 03:13:54PM -0400, R. David Murray wrote:
> 
>> Again, a program that depends on asserts is buggy.
>>
>> As Ethan pointed out we are asking about the case where someone is
>> *deliberately* setting the .pyo file up to be run as the "normal"
>> case.
> 
> You can't be sure that the .pyo file is there due to *deliberate* 
> choice. It may be accidental. Perhaps the end user has ignorantly 
> deleted the .pyc file, but failed to delete the .pyo file. Perhaps the 
> developer has merely made a mistake.

You can't just delete the .pyc file to get the .pyo file to run; 
remember in 3.x compiled files are kept in a __pycache__ folder, and if 
there is no .py file the compiled files are ignored (correct me if I'm 
wrong), so to get the either the .pyc file /or/ the .pyo file to run 
/without/ a .py file, you have to physically move the compiled file to 
where the source file should be.  It could still be accidental, but it's 
far less likely to be.


> Under current behaviour, deleting the .pyc file shouldn't matter:
> 
> - if the source file is available, that will be used
> - if not, a clear error is raised
> 
> Under the proposed change:
> 
> - if the source file is *newer* than the .pyo file, it will be used
> - but if it is missing or older, the .pyo file is used

Again, not in 3.x.

~Ethan~