rewriteutil: check for divergence
This code is adapted from the code in the evolve extension. It seems
to be equivalent as far as the evolve extension's test suite can tell
(the only impact when making their `precheck()` delegate to our
version is that error messages are less detailed).
I had to change the error message to work with "change branch of"
being inserted as the action.
Differential Revision: https://phab.mercurial-scm.org/D10518
$ 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
[50]
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
[50]
Unknown version is rejected
>>> with open('.hg/store/00changelog.i', 'wb') as fh:
... fh.write(b'\x00\x00\xbe\xef') and None
$ hg log
abort: unknown version (48879) in revlog 00changelog.i
[50]
$ 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)