contrib/check-py3-compat.py

packaging: support building WiX installers with PyOxidizer

We initially implemented PyOxidizer support for Inno installers.
That did most of the heavy work of integrating PyOxidizer into
the packaging system. Implementing WiX installer support was
pretty straightforward.

Aspects of this patch look very similar to Inno's.

The main difference is the handling of the Visual C++
Redistributable Runtime files.

The WiX installer was formerly using merge modules to
install the VC++ 9.0 runtime because this feature is
supported by the WiX installer (it isn't easily available
to Inno installers).

Our strategy for the runtime files is to install the
vcruntime140.dll file next to hg.exe just like any other
file. While we could leverage WiX's functionality for invoking
a VCRedist installer, I don't want to deal with the complexity
at this juncture. So, we let run_pyoxidizer() copy vcruntime140.dll
into the staging directory (like it does for Inno) and our
dynamic WiX XML generator picks it up as a regular file and
installs it.

We did, however, have to teach mercurial.wxs how to conditionally
use the merge modules. But this was rather straightforward.

Comparing the file layout of the WiX installers before and
after:

* Various lib/*.{pyd, dll} files no longer exist
* python27.dll was replaced by python37.dll
* vcruntime140.dll was added

All these changes are expected due to the transition to
Python 3 and to PyOxidizer, which embeded the .pyd and .dll files
in hg.exe.

Differential Revision: https://phab.mercurial-scm.org/D8477

#!/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
import warnings


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

    for f in sys.argv[1:]:
        with warnings.catch_warnings(record=True) as warns:
            fn(f)

        for w in warns:
            print(
                warnings.formatwarning(
                    w.message, w.category, w.filename, w.lineno
                ).rstrip()
            )

    sys.exit(0)