lfs: autoload the extension when cloning from repo with lfs enabled
This is based on a patch by Gregory Szorc. I made small adjustments to
clean up the messaging when the server has the extension enabled, but the
client has it disabled (to prevent autoloading). Additionally, I added
a second server capability to distinguish between the server having the
extension enabled, and the server having LFS commits. This helps prevent
unnecessary requirement propagation- the client shouldn't add a requirement
that the server doesn't have, just because the server had the extension
loaded. The TODO I had about advertising a capability when the server can
natively serve up blobs isn't relevant anymore (we've had 2 releases that
support this), so I dropped it.
Currently, we lazily add the "lfs" requirement to a repo when we first
encounter LFS data. Due to a pretxnchangegroup hook that looks for LFS
data, this can happen at the end of clone.
Now that we have more control over how repositories are created, we can
do better.
This commit adds a repo creation option to add the "lfs" requirement.
hg.clone() sets this creation option if the remote peer is advertising
lfs usage (as opposed to just support needed to push).
So, what this change effectively does is have cloned repos
automatically inherit the "lfs" requirement.
Differential Revision: https://phab.mercurial-scm.org/D5130
How to add fuzzers (partially cribbed from oss-fuzz[0]):
1) git clone https://github.com/google/oss-fuzz
2) cd oss-fuzz
3) python infra/helper.py build_image mercurial
4) docker run --cap-add=SYS_PTRACE -it -v $HG_REPO_PATH:/hg-new \
gcr.io/oss-fuzz/mercurial bash
5) cd /src
6) rm -r mercurial
7) ln -s /hg-new mercurial
8) cd mercurial
9) compile
10) ls $OUT
Step 9 is literally running the command "compile", which is part of
the docker container. Once you have that working, you can build the
fuzzers like this (in the oss-fuzz repo):
python infra/helper.py build_fuzzers --sanitizer address mercurial $HG_REPO_PATH
(you can also say "memory", "undefined" or "coverage" for
sanitizer). Then run the built fuzzers like this:
python infra/helper.py run_fuzzer mercurial -- $FUZZER
0: https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md