view contrib/check-py3-compat.py @ 29799:45fa8de47a0f

py3: provide (del|get|has|set)attr wrappers that accepts bytes

These functions will be imported automagically by our code transformer.

getattr() and setattr() are widely used in our code. We wouldn't probably
want to rewrite every single call of getattr/setattr. delattr() and hasattr()
aren't that important, but they are functions of the same kind.

#!/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].replace('.pure.', '.')
        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()
                # 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__':
    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)