py3: fix curses chunkselector fallback (when diffs are too large) on py3
Previously we showed the message using Exception.message, which is removed in
py3. Since crecordmod.fallbackerror inherits from error.Abort, we can just use
`b'%s' % exception` to print the message. This does not print the hint, but
that's fine - we don't set one. We inherit from error.Abort so that if a
codepath doesn't handle fallback specially, it exits to the terminal with a sane
message instead of an unknown exception error.
Differential Revision: https://phab.mercurial-scm.org/D7912
$ hg init empty-repo
$ cd empty-repo
Flags on revlog version 0 are rejected
>>> with open('.hg/store/00changelog.i', 'wb') as fh:
... fh.write(b'\x00\x01\x00\x00') and None
$ hg log
abort: unknown flags (0x01) in version 0 revlog 00changelog.i!
[255]
Unknown flags on revlog version 1 are rejected
>>> with open('.hg/store/00changelog.i', 'wb') as fh:
... fh.write(b'\x00\x04\x00\x01') and None
$ hg log
abort: unknown flags (0x04) in version 1 revlog 00changelog.i!
[255]
Unknown version is rejected
>>> with open('.hg/store/00changelog.i', 'wb') as fh:
... fh.write(b'\x00\x00\x00\x02') and None
$ hg log
abort: unknown version (2) in revlog 00changelog.i!
[255]
$ cd ..
Test for CVE-2016-3630
$ hg init
>>> import codecs
>>> open("a.i", "wb").write(codecs.decode(codecs.decode(
... b"""eJxjYGZgZIAAYQYGxhgom+k/FMx8YKx9ZUaKSOyqo4cnuKb8mbqHV5cBCVTMWb1Cwqkhe4Gsg9AD
... Joa3dYtcYYYBAQ8Qr4OqZAYRICPTSr5WKd/42rV36d+8/VmrNpv7NP1jQAXrQE4BqQUARngwVA==""",
... "base64"), "zlib")) and None
$ hg debugrevlogindex a.i
rev linkrev nodeid p1 p2
0 2 99e0332bd498 000000000000 000000000000
1 3 6674f57a23d8 99e0332bd498 000000000000
>>> from mercurial import revlog, vfs
>>> tvfs = vfs.vfs(b'.')
>>> tvfs.options = {b'revlogv1': True}
>>> rl = revlog.revlog(tvfs, b'a.i')
>>> rl.revision(1)
mpatchError(*'patch cannot be decoded'*) (glob)