global: use python3 in shebangs...
global: use python3 in shebangs
Python 3 is the future. We want Python scripts to be using Python 3
by default.
This change updates all `#!/usr/bin/env python` shebangs to use
`python3`.
Does this mean all scripts use or require Python 3: no.
In the test environment, the `PATH` environment variable in tests is
updated to guarantee that the Python executable used to run
run-tests.py is used. Since test scripts all now use
`#!/usr/bin/env python3`, we had to update this code to install
a `python3` symlink instead of `python`.
It is possible there are some random scripts now executed with the
incorrect Python interpreter in some contexts. However, I would argue
that this was a pre-existing bug: we should almost always be executing
new Python processes using the `sys.executable` from the originating
Python script, as `python` or `python3` won't guarantee we'll use the
same interpreter.
Differential Revision:
https://phab.mercurial-scm.org/D9273
