rust-hg-core: move from `ouroboros` to `self_cell`
`ouroboros` has a fundamental soundness problem that, while not applicable
today, could become applicable given new compiler optimizations.ยน
`self_cell` is a crate that accomplishes a lot of the same things that
`ouroboros` did while remaining sound (that is, unless a new soundness issue
is discovered) by not assuming as much about the memory layout of the program.
`self_cell` has been scrutinized heavily in the past few months by very
competent people, some from the compiler team and has shown no weaknesses
for a while, with a 1.0 stable release coming out a couple months ago.
Our internal API is exactly the same, this is just an implementation detail.
To reiterate, no actual soundness issue was found with our use of `ouroboros`,
but there might be evolutions of `rustc` (or even a future separate compiler)
that could generate unsound code.
[1] https://github.com/joshua-maros/ouroboros/issues/88
# Extension to write out fake unsupported records into the merge state
#
#
from mercurial import (
mergestate as mergestatemod,
registrar,
)
cmdtable = {}
command = registrar.command(cmdtable)
@command(
b'fakemergerecord',
[
(b'X', b'mandatory', None, b'add a fake mandatory record'),
(b'x', b'advisory', None, b'add a fake advisory record'),
],
'',
)
def fakemergerecord(ui, repo, *pats, **opts):
with repo.wlock():
ms = mergestatemod.mergestate.read(repo)
records = ms._makerecords()
if opts.get('mandatory'):
records.append((b'X', b'mandatory record'))
if opts.get('advisory'):
records.append((b'x', b'advisory record'))
ms._writerecords(records)