view tests/autodiff.py @ 33678:855a1856466d

tests: demonstrate crash when trying to rebase merge without its parents

As the test case shows, when "hg rebase -d G -r 'B + D + F'" is run on
the following graph, we crash with traceback. It's reasonable to fail
because we can not easily produce a correct rebased F. The problem is
what diff to apply to either the rebased B or the rebased D. We could
potentially produce the result by e.g. applying the (F-D) diff to the
rebased B and then applying the reverse (E-D) diff on top, but that
could result in merge conflicts in each of those steps, which we don't
have a way of dealing with. So for now, let's just add a test case to
demonstrate that we crash (i.e. the AssertionError is clearly
incorrect since the user can run into it).

  F
 /|
C E
| |
B D G
 \|/
  A

Differential Revision: https://phab.mercurial-scm.org/D212

# 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))