chg: set CHGHG before connecting to command server
cf4d2f31 (!523) changed chg to set `CHGHG` itself when spawning a new command
server, in order to ensure that the path to the `hg` executable would be checked
during server validation. (This is useful when chg is built with `HGPATHREL`).
However, that change broke chg because it failed to set `CHGHG` before trying
to connect to an existing command server. This means that if `CHGHG` is not
present in the environment, chg will always spawn a new command server, entirely
negating the point of chg.
This breakage wasn't initially caught because of the difficulty of writing
automated tests with the `HGPATHREL` feature enabled, which meant the change
was only tested manually to make sure that it fixed the problem with `HGPATHREL`
that prompted the change.
In practice, this functionality is only really useful when chg is built with
`HGPATHREL`, so I considered wrapping it in an `#ifdef` to preserve the old
behavior by default. However, this makes it hard to write tests since one would
have to explicitly set `HGPATHREL=1` when running `run-tests.py` (which is why
the original change lacked tests). It would be great if there were a way of
testing features that are gated behind conditional compilation.
#!/usr/bin/env python3
#
# check-py3-compat - check Python 3 compatibility of Mercurial files
#
# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import ast
import importlib
import os
import sys
import traceback
import warnings
def check_compat_py3(f):
"""Check Python 3 compatibility of a file with Python 3."""
with open(f, 'rb') as fh:
content = fh.read()
try:
ast.parse(content, filename=f)
except SyntaxError as e:
print('%s: invalid syntax: %s' % (f, e))
return
# Try to import the module.
# For now we only support modules in packages because figuring out module
# paths for things not in a package can be confusing.
if f.startswith(
('hgdemandimport/', 'hgext/', 'mercurial/')
) and not f.endswith('__init__.py'):
assert f.endswith('.py')
name = f.replace('/', '.')[:-3]
try:
importlib.import_module(name)
except Exception as e:
exc_type, exc_value, tb = sys.exc_info()
# We walk the stack and ignore frames from our custom importer,
# import mechanisms, and stdlib modules. This kinda/sorta
# emulates CPython behavior in import.c while also attempting
# to pin blame on a Mercurial file.
for frame in reversed(traceback.extract_tb(tb)):
if frame.name == '_call_with_frames_removed':
continue
if 'importlib' in frame.filename:
continue
if 'mercurial/__init__.py' in frame.filename:
continue
if frame.filename.startswith(sys.prefix):
continue
break
if frame.filename:
filename = os.path.basename(frame.filename)
print(
'%s: error importing: <%s> %s (error at %s:%d)'
% (f, type(e).__name__, e, filename, frame.lineno)
)
else:
print(
'%s: error importing module: <%s> %s (line %d)'
% (f, type(e).__name__, e, frame.lineno)
)
if __name__ == '__main__':
# check_compat_py3 will import every filename we specify as long as it
# starts with one of a few prefixes. It does this by converting
# specified filenames like 'mercurial/foo.py' to 'mercurial.foo' and
# importing that. When running standalone (not as part of a test), this
# means we actually import the installed versions, not the files we just
# specified. When running as test-check-py3-compat.t, we technically
# would import the correct paths, but it's cleaner to have both cases
# use the same import logic.
sys.path.insert(0, os.getcwd())
for f in sys.argv[1:]:
with warnings.catch_warnings(record=True) as warns:
check_compat_py3(f)
for w in warns:
print(
warnings.formatwarning(
w.message, w.category, w.filename, w.lineno
).rstrip()
)
sys.exit(0)