view mercurial/txnutil.py @ 32462:bb18728ea617

util: raise ParseError when parsing dates (BC)

a7dce526c462 refactored util.parsedate in order to raise ValueError instead
of Abort for using with ui.configwith. It causes several problems, putting
arbitrary bytes in ValueError can cause issues with Python 3. Moreover, we
added a function to convert ValueError exceptions back to Abort.

A better approach would be to make parsedate raises ParseError, removing
the convert function and update configwith to also catch ParseError.

The side-effect is that error message when giving an invalid date in CLI
change from:

  abort: invalid date: 'foo bar'

to:

  hg: parse error: invalid date: 'foo bar'

I'm not sure if it's an acceptable change, I found personally the error
message more clear but more verbose too.

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# 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

import errno

from . import (
    encoding,
)

def mayhavepending(root):
    '''return whether 'root' may have pending changes, which are
    visible to this process.
    '''
    return root == encoding.environ.get('HG_PENDING')

def trypending(root, vfs, filename, **kwargs):
    '''Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    '''
    if mayhavepending(root):
        try:
            return (vfs('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)