tests/autodiff.py

filemerge: use arbitraryfilectx for backups

 With in-memory merge, backup files might be overlayworkingfilectxs stored
in memory. But they could also be real files if the user's backup directory is
outside the working dir.

Rather than have two code paths everywhere, let's use arbitraryfilectx so they
can be consistent.

Differential Revision: https://phab.mercurial-scm.org/D1057

# Extension dedicated to test patch.diff() upgrade modes

from __future__ import absolute_import

from mercurial import (
    error,
    patch,
    registrar,
    scmutil,
)

cmdtable = {}
command = registrar.command(cmdtable)

@command('autodiff',
    [('', 'git', '', 'git upgrade mode (yes/no/auto/warn/abort)')],
    '[OPTION]... [FILE]...')
def autodiff(ui, repo, *pats, **opts):
    diffopts = patch.difffeatureopts(ui, opts)
    git = opts.get('git', 'no')
    brokenfiles = set()
    losedatafn = None
    if git in ('yes', 'no'):
        diffopts.git = git == 'yes'
        diffopts.upgrade = False
    elif git == 'auto':
        diffopts.git = False
        diffopts.upgrade = True
    elif git == 'warn':
        diffopts.git = False
        diffopts.upgrade = True
        def losedatafn(fn=None, **kwargs):
            brokenfiles.add(fn)
            return True
    elif git == 'abort':
        diffopts.git = False
        diffopts.upgrade = True
        def losedatafn(fn=None, **kwargs):
            raise error.Abort('losing data for %s' % fn)
    else:
        raise error.Abort('--git must be yes, no or auto')

    node1, node2 = scmutil.revpair(repo, [])
    m = scmutil.match(repo[node2], pats, opts)
    it = patch.diff(repo, node1, node2, match=m, opts=diffopts,
                    losedatafn=losedatafn)
    for chunk in it:
        ui.write(chunk)
    for fn in sorted(brokenfiles):
        ui.write(('data lost for: %s\n' % fn))