setup: only allow Python 3 from a source checkout (issue5804)
People are running `pip install Mercurial` with Python 3 and that
is working because not everything performs a Python version
compatibility check.
Modern versions of pip do recognize the "python_requires" keyword
(https://packaging.python.org/tutorials/distributing-packages/#python-requires)
which we set if using setuptools. But this isn't set nor recognized
everywhere.
To prevent people from accidentally installing Mercurial with Python
3 until Python 3 is officially supported, have setup.py fail when
run with Python 3. But don't fail if we're running from a source
checkout, as we don't want to anger Mercurial developers hacking
on Python 3 nor Mercurial's test automation running from source
checkouts. People running setup.py from source checkouts could still
fall through a Python 3 crack. But at least the
`pip install Mercurial` attempt will get nipped in the bud.
--- a/setup.py Wed Feb 21 16:51:09 2018 -0500
+++ b/setup.py Fri Feb 23 17:57:04 2018 -0800
@@ -67,6 +67,26 @@
printf(error, file=sys.stderr)
sys.exit(1)
+# We don't yet officially support Python 3. But we want to allow developers to
+# hack on. Detect and disallow running on Python 3 by default. But provide a
+# backdoor to enable working on Python 3.
+if sys.version_info[0] != 2:
+ badpython = True
+
+ # Allow Python 3 from source checkouts.
+ if os.path.isdir('.hg'):
+ badpython = False
+
+ if badpython:
+ error = """
+Mercurial only supports Python 2.7.
+Python {py} detected.
+Please re-run with Python 2.7.
+""".format(py=sys.version_info)
+
+ printf(error, file=sys.stderr)
+ sys.exit(1)
+
# Solaris Python packaging brain damage
try:
import hashlib