narrow: fix commits of empty files
The problem is that when committing a new file with empty contents (or
in general empty file with filelog p1 = -1), hg commit with narrow
doesn't create a filelog revision at all, which causes failures in
further commands.
The problem seems to be that:
- hg thinks that instead of creating a new filelog revision, it can
use the filelog's p1 (the nullrev)
- because it thinks the file contents is the same in that revision and
in p1
- because `narrowfilelog.cmp(nullrev, b'')` is True (unlike with
`filelog.cmp`)
It's not clear to me which `cmp` behaves better. But I think it makes
sense to change the commit code to not to "reuse" the null rev when
adding an empty file with filelog p1 == filelog p2 == -1. This is
consistent with never writing the null rev in the manifest, which `hg
verify` claims is an invariant:
```
inside/c@4: manifest refers to unknown revision 000000000000
```
Differential Revision: https://phab.mercurial-scm.org/D11400
# hgdemandimport - global demand-loading of modules for Mercurial
#
# Copyright 2017 Facebook Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''demandimport - automatic demand-loading of modules'''
# This is in a separate package from mercurial because in Python 3,
# demand loading is per-package. Keeping demandimport in the mercurial package
# would disable demand loading for any modules in mercurial.
from __future__ import absolute_import
import os
import sys
if sys.version_info[0] >= 3:
from . import demandimportpy3 as demandimport
else:
from . import demandimportpy2 as demandimport
# Full module names which can't be lazy imported.
# Extensions can add to this set.
IGNORES = {
'__future__',
'_hashlib',
# ImportError during pkg_resources/__init__.py:fixup_namespace_package
'_imp',
'_xmlplus',
'fcntl',
'nt', # pathlib2 tests the existence of built-in 'nt' module
'win32com.gen_py',
'win32com.shell', # 'appdirs' tries to import win32com.shell
'_winreg', # 2.7 mimetypes needs immediate ImportError
'pythoncom',
# imported by tarfile, not available under Windows
'pwd',
'grp',
# imported by profile, itself imported by hotshot.stats,
# not available under Windows
'resource',
# this trips up many extension authors
'gtk',
# setuptools' pkg_resources.py expects "from __main__ import x" to
# raise ImportError if x not defined
'__main__',
'_ast', # https://bugs.python.org/issue41631
'_ssl', # conditional imports in the stdlib, issue1964
'_sre', # issue4920
'rfc822',
'mimetools',
'sqlalchemy.events', # has import-time side effects (issue5085)
'sqlalchemy.dialects', # similar problems as above
# setuptools 8 expects this module to explode early when not on windows
'distutils.msvc9compiler',
'__builtin__',
'builtins',
'urwid.command_map', # for pudb
'lzma',
}
_pypy = '__pypy__' in sys.builtin_module_names
if _pypy:
# _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5)
IGNORES.add('_ctypes.pointer')
demandimport.init(IGNORES)
# Re-export.
isenabled = demandimport.isenabled
disable = demandimport.disable
deactivated = demandimport.deactivated
def enable():
# chg pre-imports modules so do not enable demandimport for it
if (
'CHGINTERNALMARK' not in os.environ
and os.environ.get('HGDEMANDIMPORT') != 'disable'
):
demandimport.enable()