Subject: Re: `git p4` broken on machines which do not have python on path

From: Junio C Hamano <[email-masked]>
Date: Thu, 06 Feb 2025 15:17:13 -0800

"brian m. carlson" <[email-masked]> writes:

> On 2025-02-06 at 02:12:02, Kapil Somani wrote:
>> Thanks for quick response Brian
>> 
>> Yes, our team compiles git for use within our organization.
>> I'll reach out to them and see if they can provide path during build.
>> 
>> Meanwhile, I was able to update copy of the git (compiled by my team) to
>> use python3 on shebang line.
>> It appears that the git-p4 is compatible with Python3. Is git team planning
>> to update it near future?
>
> It's my understanding that it's designed to work with both Python 2 and
> 3.  It's unlikely that the shebang will be updated until it's no longer

Correct.  The CI has jobs to try git-p4 with both python2 and python3
since Mar 2020.

> guaranteed to work with Python 2, since `python` is more generic than
> `python3`.  When that is, I don't know, since I don't use Perforce and
> don't maintain git-p4, which has a separate maintainer.

I am not sure what story about shebang is discussed here.

If the complaint is "your script says '/usr/bin/env python', but my
users don't have 'python' on their $PATH", I think that is barking
up a wrong tree.  As a general principle, we try not to rely on
"env".

Just like other scripts, we munge git-p4.py script to replace the
shebang line to use the path to the python binary specified by the
builder into resulting git-p4 "executable" file that is installed.

We do this (not specifically for git-p4 but as a general principle)
because we do not want to get affected by random customized versions
of stuff end-users install on their $PATH that overrides the ones
from the system that builders determined to be used by Git.

Is the complaint that "on my system there are /usr/bin/python2 and
/usr/bin/python3 but no vanilla /usr/bin/python installed"?  

So it is your responsibility to tell the build procedure that you
want to use "/usr/bin/python3", as the build procedure defaults to
"/usr/bin/python" when you do not specify any.