How to build stable 3.9 branch from fork and clone of cpython

[Terry Reedy]

On 5/18/2021 3:00 AM, Chris Angelico wrote:
> On Tue, May 18, 2021 at 4:33 PM <pjfarley3 at earthlink.net> wrote:
>>
>> I am following the "Getting Started" section of the Python Developers Guide,
>> but when I build the first version to verify everything builds, it builds
>> branch 3.11.
>>
>>
>>
>> If I want to build and contribute to branch 3.9, how do I set that up
>> please?
>>
> 
> git checkout 3.9
> 
> That should switch you to the branch, replacing all the (tracked)
> files in the build directory with the corresponding files from 3.9.
> 
> Be aware that most development is going to happen on the master branch
> (or the main branch, whichever one you have),

It should be 'main' for any python/??? repository.  If one forked and 
cloned before the switch, one should rename 'master' to 'main' both 
locally and on the fork.  Github has directions somewhere.  It might 
provide them if one attempts a PR against 'master'.  There may also be 
something in the devguide.

The only time an initial contribution would be for 3.9 would be for a 
bug that only exists in 3.9, which is very rare.

> and branches like 3.9
> are going to get backported patches; so any change you're planning to
> contribute to 3.9 is going to need to work correctly on both branches.

It must be 'main' for any python/??? repository.  The only time an 
initial contribution would be for 3.9 would be for a bug that only 
exists in 3.9, which is very rare.

-- 
Terry Jan Reedy