mercurial/testing/__init__.py

dirstate: remove need_delay logic

Now that all¹ stored mtime are non ambiguous, we no longer need to apply the `need_delay` step.
The need delay logic was not great are mtime gathered during longer operation
could be ambiguous but younger than the `dirstate.write` call time.

So, we don't need that logic anymore and can drop it

This make the code much simpler. The code related to the test extension faking
the dirstate write is now obsolete and associated test will be migrated as
follow up. They currently do not break.

[1] except the ones from `hg update`, but `need_delay` no longer help for them
either.

Differential Revision: https://phab.mercurial-scm.org/D11796

from __future__ import (
    absolute_import,
    division,
)

import os
import time


# work around check-code complains
#
# This is a simple log level module doing simple test related work, we can't
# import more things, and we do not need it.
environ = getattr(os, 'environ')


def _timeout_factor():
    """return the current modification to timeout"""
    default = int(environ.get('HGTEST_TIMEOUT_DEFAULT', 360))
    current = int(environ.get('HGTEST_TIMEOUT', default))
    if current == 0:
        return 1
    return current / float(default)


def wait_file(path, timeout=10):
    timeout *= _timeout_factor()
    start = time.time()
    while not os.path.exists(path):
        if timeout and time.time() - start > timeout:
            raise RuntimeError(b"timed out waiting for file: %s" % path)
        time.sleep(0.01)


def write_file(path, content=b''):
    if content:
        write_path = b'%s.tmp' % path
    else:
        write_path = path
    with open(write_path, 'wb') as f:
        f.write(content)
    if path != write_path:
        os.rename(write_path, path)