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
#!/usr/bin/env python3
from __future__ import absolute_import, print_function
import sys
from mercurial import (
commands,
localrepo,
ui as uimod,
)
print_ = print
def print(*args, **kwargs):
"""print() wrapper that flushes stdout buffers to avoid py3 buffer issues
We could also just write directly to sys.stdout.buffer the way the
ui object will, but this was easier for porting the test.
"""
print_(*args, **kwargs)
sys.stdout.flush()
u = uimod.ui.load()
print('% creating repo')
repo = localrepo.instance(u, b'.', create=True)
f = open('test.py', 'w')
try:
f.write('foo\n')
finally:
f.close
print('% add and commit')
commands.add(u, repo, b'test.py')
commands.commit(u, repo, message=b'*')
commands.status(u, repo, clean=True)
print('% change')
f = open('test.py', 'w')
try:
f.write('bar\n')
finally:
f.close()
# this would return clean instead of changed before the fix
commands.status(u, repo, clean=True, modified=True)