Mercurial > hg
view tests/test-manifestv2.t @ 30435:b86a448a2965
zstd: vendor python-zstandard 0.5.0
As the commit message for the previous changeset says, we wish
for zstd to be a 1st class citizen in Mercurial. To make that
happen, we need to enable Python to talk to the zstd C API. And
that requires bindings.
This commit vendors a copy of existing Python bindings. Why do we
need to vendor? As the commit message of the previous commit says,
relying on systems in the wild to have the bindings or zstd present
is a losing proposition. By distributing the zstd and bindings with
Mercurial, we significantly increase our chances that zstd will
work. Since zstd will deliver a better end-user experience by
achieving better performance, this benefits our users. Another
reason is that the Python bindings still aren't stable and the
API is somewhat fluid. While Mercurial could be coded to target
multiple versions of the Python bindings, it is safer to bundle
an explicit, known working version.
The added Python bindings are mostly a fully-featured interface
to the zstd C API. They allow one-shot operations, streaming,
reading and writing from objects implements the file object
protocol, dictionary compression, control over low-level compression
parameters, and more. The Python bindings work on Python 2.6,
2.7, and 3.3+ and have been tested on Linux and Windows. There are
CFFI bindings, but they are lacking compared to the C extension.
Upstream work will be needed before we can support zstd with PyPy.
But it will be possible.
The files added in this commit come from Git commit
e637c1b214d5f869cf8116c550dcae23ec13b677 from
https://github.com/indygreg/python-zstandard and are added without
modifications. Some files from the upstream repository have been
omitted, namely files related to continuous integration.
In the spirit of full disclosure, I'm the maintainer of the
"python-zstandard" project and have authored 100% of the code
added in this commit. Unfortunately, the Python bindings have
not been formally code reviewed by anyone. While I've tested
much of the code thoroughly (I even have tests that fuzz APIs),
there's a good chance there are bugs, memory leaks, not well
thought out APIs, etc. If someone wants to review the code and
send feedback to the GitHub project, it would be greatly
appreciated.
Despite my involvement with both projects, my opinions of code
style differ from Mercurial's. The code in this commit introduces
numerous code style violations in Mercurial's linters. So, the code
is excluded from most lints. However, some violations I agree with.
These have been added to the known violations ignore list for now.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 10 Nov 2016 22:15:58 -0800 |
parents | 2329ca3ebc7a |
children | eb586ed5d8ce |
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Create repo with old manifest $ cat << EOF >> $HGRCPATH > [format] > usegeneraldelta=yes > EOF $ hg init existing $ cd existing $ echo footext > foo $ hg add foo $ hg commit -m initial We're using v1, so no manifestv2 entry is in requires yet. $ grep manifestv2 .hg/requires [1] Let's clone this with manifestv2 enabled to switch to the new format for future commits. $ cd .. $ hg clone --pull existing new --config experimental.manifestv2=1 requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd new Check that entry was added to .hg/requires. $ grep manifestv2 .hg/requires manifestv2 Make a new commit. $ echo newfootext > foo $ hg commit -m new Check that the manifest actually switched to v2. $ hg debugdata -m 0 foo\x0021e958b1dca695a60ee2e9cf151753204ee0f9e9 (esc) $ hg debugdata -m 1 \x00 (esc) \x00foo\x00 (esc) I\xab\x7f\xb8(\x83\xcas\x15\x9d\xc2\xd3\xd3:5\x08\xbad5_ (esc) Check that manifestv2 is used if the requirement is present, even if it's disabled in the config. $ echo newerfootext > foo $ hg --config experimental.manifestv2=False commit -m newer $ hg debugdata -m 2 \x00 (esc) \x00foo\x00 (esc) \xa6\xb1\xfb\xef]\x91\xa1\x19`\xf3.#\x90S\xf8\x06 \xe2\x19\x00 (esc) Check that we can still read v1 manifests. $ hg files -r 0 foo $ cd .. Check that entry is added to .hg/requires on repo creation $ hg --config experimental.manifestv2=True init repo $ cd repo $ grep manifestv2 .hg/requires manifestv2 Set up simple repo $ echo a > file1 $ echo b > file2 $ echo c > file3 $ hg ci -Aqm 'initial' $ echo d > file2 $ hg ci -m 'modify file2' Check that 'hg verify', which uses manifest.readdelta(), works $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 3 files, 2 changesets, 4 total revisions Check that manifest revlog is smaller than for v1 $ hg debugindex -m rev offset length delta linkrev nodeid p1 p2 0 0 81 -1 0 57361477c778 000000000000 000000000000 1 81 33 0 1 aeaab5a2ef74 57361477c778 000000000000