view tests/autodiff.py @ 44667:b561f3a68e41 stable

discovery: avoid wrongly saying there are nothing to pull

We can get in a situation where a revision passed through `hg pull --rev REV`
are available on the server, but not a descendant of the advertised server
heads.

For example the server could lying be during heads advertisement, to hide some
pull request. Or obsolete/hidden content could be explicitly pulled.

So in this case the lookup associated to `REV` returned successfully, but the
normal discovery will find all advertised heads already known locally. This flip
a special boolean `anyinc` that will prevent any fetch attempt, preventing `REV`
to be pulled over.

We add three line of code to detect this case and make sure a pull actually
happens.

My main target is to make some third party extensions happy (I expect the
associated test to move upstream with the extension). However this fix already
make some of the `infinitepush` test happier.

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

from __future__ import absolute_import

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

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


@command(
    b'autodiff',
    [(b'', b'git', b'', b'git upgrade mode (yes/no/auto/warn/abort)')],
    b'[OPTION]... [FILE]...',
)
def autodiff(ui, repo, *pats, **opts):
    opts = pycompat.byteskwargs(opts)
    diffopts = patch.difffeatureopts(ui, opts)
    git = opts.get(b'git', b'no')
    brokenfiles = set()
    losedatafn = None
    if git in (b'yes', b'no'):
        diffopts.git = git == b'yes'
        diffopts.upgrade = False
    elif git == b'auto':
        diffopts.git = False
        diffopts.upgrade = True
    elif git == b'warn':
        diffopts.git = False
        diffopts.upgrade = True

        def losedatafn(fn=None, **kwargs):
            brokenfiles.add(fn)
            return True

    elif git == b'abort':
        diffopts.git = False
        diffopts.upgrade = True

        def losedatafn(fn=None, **kwargs):
            raise error.Abort(b'losing data for %s' % fn)

    else:
        raise error.Abort(b'--git must be yes, no or auto')

    ctx1, ctx2 = scmutil.revpair(repo, [])
    m = scmutil.match(ctx2, pats, opts)
    it = patch.diff(
        repo,
        ctx1.node(),
        ctx2.node(),
        match=m,
        opts=diffopts,
        losedatafn=losedatafn,
    )
    for chunk in it:
        ui.write(chunk)
    for fn in sorted(brokenfiles):
        ui.write((b'data lost for: %s\n' % fn))