[Python-Dev] do people use sys._mercurial? (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Fri Jan 22 21:47:14 EST 2016

On 23 January 2016 at 09:44, Brett Cannon <brett at python.org> wrote:

Since we are going to be switching over to Git, sys.mercurial is going to be made to return a dummy value of ('CPython', '', '') once we switch to Git. But my question is do we bother to replace it with sys.git? I wanted to make sure that the effort is worth it to keep changing these VCS-specific attributes every time we change our VCS (and no, we are not going to adopt a generic one; already had that debate). So do please speak up if you actually have found value from sys.mercurial.

It's incorporated into the output of "platform.python_(branch|revision|build)()", so I assume most people would use those if they needed to report exact build information, rather than accessing the attribute directly.

We also use it ourselves in printing the appropriate banner when running an interactive prompt (note the first line of the banner):

Python 3.6.0a0 (default:32a4e7b337c9, Jan 23 2016, 12:30:00) [GCC 5.3.1 20151207 (Red Hat 5.3.1-2)] on linux Type "help", "copyright", "credits" or "license" for more information.

import sys sys.mercurial ('CPython', 'default', '32a4e7b337c9')

And the regression test suite:

$ ./python -m test == CPython 3.6.0a0 (default:32a4e7b337c9, Jan 23 2016, 12:30:00) [GCC 5.3.1 20151207 (Red Hat 5.3.1-2)] == Linux-4.3.3-301.fc23.x86_64-x86_64-with-fedora-23-Twenty_Three little-endian == hash algorithm: siphash24 64bit == /home/ncoghlan/devel/cpython/build/test_python_13167 Testing with flags: sys.flags(debug=0, inspect=0, interactive=0, optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0, ignore_environment=0, verbose=0, bytes_warning=0, quiet=0, hash_randomization=1, isolated=0) [ 1/401] test_grammar ...

I guess that means "Update platform.py, and test the interactive prompt and regression test banners still work as expected when built from git" needs to be added to the CPython migration part of the PEP. (In looking into this, I found several of the docstrings in platform.py still referred to Subversion, even though the platform._sys_version() helping had been updated to handle Mercurial)

Cheers, Nick.

-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia

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