contrib/check-py3-compat.py

copies: simplify the handling of merges

Instead of stacking copies for both parent on the head, we move copies outside
of the heap into a dedicated dictionary. The two side of merge can we merged
sooner, making the algorithm simpler.

This simplicity reflect in the heap structure and speed up the execution for
copies involving a large amount of merges.

Here are timing for perfpathcopies of multiple revision pairs.
- filelog: timing using filelog (with the introrev condition dropped)
- base:    this series base
- before:  the parent of this changeset
- after:   this changeset

revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29
filelog: ! wall 3.679613 comb 3.680000 user 3.580000 sys 0.100000 (median of 3)
base:    ! wall 8.884369 comb 8.880000 user 8.850000 sys 0.030000 (median of 3)
before:  ! wall 8.443747 comb 8.420000 user 8.410000 sys 0.010000 (median of 3)
after:   ! wall 4.697917 comb 4.690000 user 4.660000 sys 0.030000 (median of 3)
revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2
filelog: ! wall 0.003357 comb 0.010000 user 0.010000 sys 0.000000 (median of 781)
base:    ! wall 12.398524 comb 12.400000 user 12.330000 sys 0.070000 (median of 3)
before:  ! wall 10.852593 comb 10.850000 user 10.800000 sys 0.050000 (median of 3)
after:   ! wall 6.750832 comb 6.750000 user 6.640000 sys 0.110000 (median of 3)
revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0
filelog: ! wall 2.754687 comb 2.760000 user 2.650000 sys 0.110000 (median of 4)
base:    ! wall 1.423166 comb 1.420000 user 1.400000 sys 0.020000 (median of 8)
before:  ! wall 1.068041 comb 1.060000 user 1.050000 sys 0.010000 (median of 10)
after:   ! wall 1.045916 comb 1.050000 user 1.040000 sys 0.010000 (median of 10)
revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f
filelog: ! wall 1.552293 comb 1.550000 user 1.510000 sys 0.040000 (median of 6
base:    ! wall 0.022662 comb 0.020000 user 0.020000 sys 0.000000 (median of 128)
before:  ! wall 0.021111 comb 0.020000 user 0.020000 sys 0.000000 (median of 139)
after:   ! wall 0.021577 comb 0.020000 user 0.020000 sys 0.000000 (median of 138)
revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63
filelog: ! wall 1.500983 comb 1.500000 user 1.420000 sys 0.080000 (median of 7)
base:    ! wall 0.006956 comb 0.010000 user 0.010000 sys 0.000000 (median of 392)
before:  ! wall 0.004356 comb 0.010000 user 0.010000 sys 0.000000 (median of 675)
after:   ! wall 0.004329 comb 0.000000 user 0.000000 sys 0.000000 (median of 682)
revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e
filelog: ! wall 0.011745 comb 0.020000 user 0.020000 sys 0.000000 (median of 250)
base:    ! wall 0.000156 comb 0.000000 user 0.000000 sys 0.000000 (median of 17180)
before:  ! wall 0.000100 comb 0.000000 user 0.000000 sys 0.000000 (median of 26912)
after:   ! wall 0.000105 comb 0.000000 user 0.000000 sys 0.000000 (median of 25689)
revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe
filelog: ! wall 3.228230 comb 3.230000 user 3.110000 sys 0.120000 (median of 4)
base:    ! wall 0.997640 comb 1.000000 user 0.980000 sys 0.020000 (median of 10)
before:  ! wall 0.778291 comb 0.780000 user 0.780000 sys 0.000000 (median of 13)
after:   ! wall 0.706594 comb 0.710000 user 0.710000 sys 0.000000 (median of 15)
revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d
filelog: ! wall 1.052501 comb 1.060000 user 1.040000 sys 0.020000 (median of 10
base:    ! wall 0.214519 comb 0.220000 user 0.220000 sys 0.000000 (median of 45)
before:  ! wall 0.160804 comb 0.160000 user 0.160000 sys 0.000000 (median of 62)
after:   ! wall 0.163736 comb 0.160000 user 0.160000 sys 0.000000 (median of 60)

Differential Revision: https://phab.mercurial-scm.org/D7069

#!/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 |= 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, 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)