Petr Viktorin <encu...@gmail.com> writes: > In Fedora, I found that PEP 394's strict recommendation that `python` > points to `python2` is holding us back.
I have read the message, but I don't see how you draw the link that PEP 394 is holding you back. > The problems are: > - For developers that are not following the language's development, > the fact that `python` invokes `python2` sends a strong signal that 2 > is somehow the preferred version, and it's OK to start new projects in > it. I agree with the statement you make later in the message: > […] we feel that the only way to *enforce* that guidelines is to > provide environments where the `python` command does not work (unless > explicitly installed). Yes. The ‘python’ command is confusing, for the reasons you say. There should be ‘python2’ and ‘python3’ commands for Python 2 and Python 3 respectively, and no ‘python’ command should be installed by the operating system. The fact that ‘/usr/bin/python’ exists is an historical accident, and I agree with the proposal you state: the best way to correct the confusion is to bar the confusing command from being installed by packages. > - Users and sysadmins that *do* want to “live in the future” are > switching the symlink to `python3` themselves. We would like to give > them a supported, documented way to do so -- and make surer they're > aware of the caveats. The supported, documented way to add a command pointing to a different command already exists, and there is no need to make a Python-specific special case. Users who want to make a ‘python’ alias can do so in their shell; this is supported and documented. Users who want to add a new command file can add a suitable directory (e.g. ‘$HOME/bin’) to their ‘PATH’ variable, and put a symlink in there named ‘python’. This is supported and documented. Sysadmins who want to create a system-wide command ‘python’ can put a symlink at ‘/usr/local/bin/python’. This is supported and documented. I disagree with making some special-case extra way; that would be both cunfusing and superfluous. > - The `python` command is still not available out-of-the box on macOS, > so it didn't completely live up to the expectation of being the > cross-platform way to launch 2/3 source compatile scripts. That is one of the minor ways which macOS fails to conform to community-agreed conventions. We should not let that intransigence distort our discussion of best practices. > To help solve these, I would like to relax recommendations on the Unix > ``python -> python2`` symlink in these cases: For the above reasons, I disagree that PEP 394 is limiting what you want to do on free-software operating systems. For non-free operating systems, I don't think the already-discussed PEP 394 should be weakened if the operating system vendor fails to conform. > - Users and administrators can, by a deliberate action, change > ``python`` to invoke Python 3. Yes. That is well-known and long-standardised on Unix operating systems, and is much more broadly understood than any Python-specific special case would be. So I don't see how anyone is being held back. I trust that PEP 394 will not be weakened in its effect, and I wish you well with using the already-supported, already-documented, PEP-394 compatible means to add local customisations for a ‘python’ command. -- \ “Pity the meek, for they shall inherit the earth.” —Donald | `\ Robert Perry Marquis | _o__) | Ben Finney _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
