contrib/check-py3-compat.py

destutil: add the ability to specify a search space for rebase destination

In the 'hg pull --rebase', we don't want to pick a rebase destination unrelated
to the pull, we lay down basic infrastructure to allow such restriction on
stable (before 3.8 release) in this case. See issue 5214 for details.

Actual usage and test will be in the next patch.

#!/usr/bin/env python
#
# check-py3-compat - check Python 3 compatibility of Mercurial files
#
# Copyright 2015 Gregory Szorc <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import, print_function

import ast
import imp
import os
import sys
import traceback

def check_compat_py2(f):
    """Check Python 3 compatibility for a file with Python 2"""
    with open(f, 'rb') as fh:
        content = fh.read()
    root = ast.parse(content)

    # Ignore empty files.
    if not root.body:
        return

    futures = set()
    haveprint = False
    for node in ast.walk(root):
        if isinstance(node, ast.ImportFrom):
            if node.module == '__future__':
                futures |= set(n.name for n in node.names)
        elif isinstance(node, ast.Print):
            haveprint = True

    if 'absolute_import' not in futures:
        print('%s not using absolute_import' % f)
    if haveprint and 'print_function' not in futures:
        print('%s requires print_function' % f)

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)
    except SyntaxError as e:
        print('%s: invalid syntax: %s' % (f, e))
        return

    # Try to import the module.
    # For now we only support mercurial.* and hgext.* modules because figuring
    # out module paths for things not in a package can be confusing.
    if f.startswith(('hgext/', 'mercurial/')) and not f.endswith('__init__.py'):
        assert f.endswith('.py')
        name = f.replace('/', '.')[:-3]
        with open(f, 'r') as fh:
            try:
                imp.load_module(name, fh, '', ('py', 'r', imp.PY_SOURCE))
            except Exception as e:
                exc_type, exc_value, tb = sys.exc_info()
                frame = traceback.extract_tb(tb)[-1]

                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__':
    if sys.version_info[0] == 2:
        fn = check_compat_py2
    else:
        fn = check_compat_py3

    for f in sys.argv[1:]:
        fn(f)

    sys.exit(0)