contrib/fuzz/manifest_corpus.py

fuzz: new fuzzer for cext/manifest.c

This is a bit messy, because lazymanifest is tightly coupled to the
cpython API for performance reasons. As a result, we have to build a
whole Python without pymalloc (so ASAN can help us out) and link
against that. Then we have to use an embedded Python interpreter. We
could manually drive the lazymanifest in C from that point, but
experimentally just using PyEval_EvalCode isn't really any slower so
we may as well do that and write the innermost guts of the fuzzer in
Python.

Leak detection is currently disabled for this fuzzer because there are
a few global-lifetime things in our extensions that we more or less
intentionally leak and I didn't want to take the detour to work around
that for now.

This should not be pushed to our repo until
https://github.com/google/oss-fuzz/pull/1853 is merged, as this
depends on having the Python tarball around.

Differential Revision: https://phab.mercurial-scm.org/D4879

from __future__ import absolute_import, print_function

import argparse
import zipfile

ap = argparse.ArgumentParser()
ap.add_argument("out", metavar="some.zip", type=str, nargs=1)
args = ap.parse_args()

with zipfile.ZipFile(args.out[0], "w", zipfile.ZIP_STORED) as zf:
    zf.writestr("manifest_zero",
'''PKG-INFO\09b3ed8f2b81095a13064402e930565f083346e9a
README\080b6e76643dcb44d4bc729e932fc464b3e36dbe3
hg\0b6444347c629cc058d478023905cfb83b7f5bb9d
mercurial/__init__.py\0b80de5d138758541c5f05265ad144ab9fa86d1db
mercurial/byterange.py\017f5a9fbd99622f31a392c33ac1e903925dc80ed
mercurial/fancyopts.py\0b6f52e23e356748c5039313d8b639cda16bf67ba
mercurial/hg.py\023cc12f225f1b42f32dc0d897a4f95a38ddc8f4a
mercurial/mdiff.py\0a05f65c44bfbeec6a42336cd2ff0b30217899ca3
mercurial/revlog.py\0217bc3fde6d82c0210cf56aeae11d05a03f35b2b
mercurial/transaction.py\09d180df101dc14ce3dd582fd998b36c98b3e39aa
notes.txt\0703afcec5edb749cf5cec67831f554d6da13f2fb
setup.py\0ccf3f6daf0f13101ca73631f7a1769e328b472c9
tkmerge\03c922edb43a9c143682f7bc7b00f98b3c756ebe7
''')
    zf.writestr("badmanifest_shorthashes",
                "narf\0aa\nnarf2\0aaa\n")
    zf.writestr("badmanifest_nonull",
                "narf\0cccccccccccccccccccccccccccccccccccccccc\n"
                "narf2aaaaaaaaaaaaaaaaaaaa\n")