view contrib/check-py3-compat.py @ 39055:ef3d3a2f9aa5

changegroup: refactor delta parent code

We had recently abstracted the delta parent functions to
facilitate extracting code from cgpacker. Now that we're in
a better place, it is time to revisit the design.

Changegroup version 1 requires that the previous node be used as the
delta parent. Later versions allow any available node to be used
as the base.

In the case where an arbitrary parent can be used, the choice of
a delta parent is best left in the hands of the storage backend.
So it makes sense for the delta parent selection to be hidden
away in the storage layer. This means deferring the choice of the
delta parent selection function to as close to delta generation
time as possible.

This commit moves the delta selection logic to essentially just
before delta generation. However, because changegroup version 1
limits what we can do, we have retained the ability to force a
delta against the previous revision.

As part of this, I realized that the ellipsis parent function was
unused! That's because ellipsis mode always sends full revisions
and not deltas.

Differential Revision: https://phab.mercurial-scm.org/D4214

#!/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 importlib
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 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__':
    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)