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.
prepare repo
$ hg init a
$ cd a
$ echo "some text" > FOO.txt
$ echo "another text" > bar.txt
$ echo "more text" > QUICK.txt
$ hg add
adding FOO.txt
adding QUICK.txt
adding bar.txt
$ hg ci -mtest1
verify
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 1 changesets, 3 total revisions
verify with journal
$ touch .hg/store/journal
$ hg verify
abandoned transaction found - run hg recover
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 1 changesets, 3 total revisions
$ rm .hg/store/journal
introduce some bugs in repo
$ cd .hg/store/data
$ mv _f_o_o.txt.i X_f_o_o.txt.i
$ mv bar.txt.i xbar.txt.i
$ rm _q_u_i_c_k.txt.i
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
warning: revlog 'data/FOO.txt.i' not in fncache!
0: empty or missing FOO.txt
FOO.txt@0: manifest refers to unknown revision f62022d3d590
warning: revlog 'data/QUICK.txt.i' not in fncache!
0: empty or missing QUICK.txt
QUICK.txt@0: manifest refers to unknown revision 88b857db8eba
warning: revlog 'data/bar.txt.i' not in fncache!
0: empty or missing bar.txt
bar.txt@0: manifest refers to unknown revision 256559129457
3 files, 1 changesets, 0 total revisions
3 warnings encountered!
hint: run "hg debugrebuildfncache" to recover from corrupt fncache
6 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cd ../../..
$ cd ..
Set up a repo for testing missing revlog entries
$ hg init missing-entries
$ cd missing-entries
$ echo 0 > file
$ hg ci -Aqm0
$ cp -r .hg/store .hg/store-partial
$ echo 1 > file
$ hg ci -Aqm1
$ cp -r .hg/store .hg/store-full
Entire changelog missing
$ rm .hg/store/00changelog.*
$ hg verify -q
0: empty or missing changelog
manifest@0: d0b6632564d4 not in changesets
manifest@1: 941fc4534185 not in changesets
3 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Entire manifest log missing
$ rm .hg/store/00manifest.*
$ hg verify -q
0: empty or missing manifest
1 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Entire filelog missing
$ rm .hg/store/data/file.*
$ hg verify -q
warning: revlog 'data/file.i' not in fncache!
0: empty or missing file
file@0: manifest refers to unknown revision 362fef284ce2
file@1: manifest refers to unknown revision c10f2164107d
1 warnings encountered!
hint: run "hg debugrebuildfncache" to recover from corrupt fncache
3 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Entire changelog and manifest log missing
$ rm .hg/store/00changelog.*
$ rm .hg/store/00manifest.*
$ hg verify -q
warning: orphan revlog 'data/file.i'
1 warnings encountered!
$ cp -r .hg/store-full/. .hg/store
Entire changelog and filelog missing
$ rm .hg/store/00changelog.*
$ rm .hg/store/data/file.*
$ hg verify -q
0: empty or missing changelog
manifest@0: d0b6632564d4 not in changesets
manifest@1: 941fc4534185 not in changesets
warning: revlog 'data/file.i' not in fncache!
?: empty or missing file
file@0: manifest refers to unknown revision 362fef284ce2
file@1: manifest refers to unknown revision c10f2164107d
1 warnings encountered!
hint: run "hg debugrebuildfncache" to recover from corrupt fncache
6 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Entire manifest log and filelog missing
$ rm .hg/store/00manifest.*
$ rm .hg/store/data/file.*
$ hg verify -q
0: empty or missing manifest
warning: revlog 'data/file.i' not in fncache!
0: empty or missing file
1 warnings encountered!
hint: run "hg debugrebuildfncache" to recover from corrupt fncache
2 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Changelog missing entry
$ cp -f .hg/store-partial/00changelog.* .hg/store
$ hg verify -q
manifest@?: rev 1 points to nonexistent changeset 1
manifest@?: 941fc4534185 not in changesets
file@?: rev 1 points to nonexistent changeset 1
(expected 0)
1 warnings encountered!
3 integrity errors encountered!
[1]
$ cp -r .hg/store-full/. .hg/store
Manifest log missing entry
$ cp -f .hg/store-partial/00manifest.* .hg/store
$ hg verify -q
manifest@1: changeset refers to unknown revision 941fc4534185
file@1: c10f2164107d not in manifests
2 integrity errors encountered!
(first damaged changeset appears to be 1)
[1]
$ cp -r .hg/store-full/. .hg/store
Filelog missing entry
$ cp -f .hg/store-partial/data/file.* .hg/store/data
$ hg verify -q
file@1: manifest refers to unknown revision c10f2164107d
1 integrity errors encountered!
(first damaged changeset appears to be 1)
[1]
$ cp -r .hg/store-full/. .hg/store
Changelog and manifest log missing entry
$ cp -f .hg/store-partial/00changelog.* .hg/store
$ cp -f .hg/store-partial/00manifest.* .hg/store
$ hg verify -q
file@?: rev 1 points to nonexistent changeset 1
(expected 0)
file@?: c10f2164107d not in manifests
1 warnings encountered!
2 integrity errors encountered!
[1]
$ cp -r .hg/store-full/. .hg/store
Changelog and filelog missing entry
$ cp -f .hg/store-partial/00changelog.* .hg/store
$ cp -f .hg/store-partial/data/file.* .hg/store/data
$ hg verify -q
manifest@?: rev 1 points to nonexistent changeset 1
manifest@?: 941fc4534185 not in changesets
file@?: manifest refers to unknown revision c10f2164107d
3 integrity errors encountered!
[1]
$ cp -r .hg/store-full/. .hg/store
Manifest and filelog missing entry
$ cp -f .hg/store-partial/00manifest.* .hg/store
$ cp -f .hg/store-partial/data/file.* .hg/store/data
$ hg verify -q
manifest@1: changeset refers to unknown revision 941fc4534185
1 integrity errors encountered!
(first damaged changeset appears to be 1)
[1]
$ cp -r .hg/store-full/. .hg/store
Corrupt changelog base node to cause failure to read revision
$ printf abcd | dd conv=notrunc of=.hg/store/00changelog.i bs=1 seek=16 \
> 2> /dev/null
$ hg verify -q
0: unpacking changeset 08b1860757c2: * (glob)
manifest@?: rev 0 points to unexpected changeset 0
manifest@?: d0b6632564d4 not in changesets
file@?: rev 0 points to unexpected changeset 0
(expected 1)
1 warnings encountered!
4 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Corrupt manifest log base node to cause failure to read revision
$ printf abcd | dd conv=notrunc of=.hg/store/00manifest.i bs=1 seek=16 \
> 2> /dev/null
$ hg verify -q
manifest@0: reading delta d0b6632564d4: * (glob)
file@0: 362fef284ce2 not in manifests
2 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
Corrupt filelog base node to cause failure to read revision
$ printf abcd | dd conv=notrunc of=.hg/store/data/file.i bs=1 seek=16 \
> 2> /dev/null
$ hg verify -q
file@0: unpacking 362fef284ce2: * (glob)
1 integrity errors encountered!
(first damaged changeset appears to be 0)
[1]
$ cp -r .hg/store-full/. .hg/store
$ cd ..
test changelog without a manifest
$ hg init b
$ cd b
$ hg branch foo
marked working directory as branch foo
(branches are permanent and global, did you want a bookmark?)
$ hg ci -m branchfoo
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 1 changesets, 0 total revisions
test revlog corruption
$ touch a
$ hg add a
$ hg ci -m a
$ echo 'corrupted' > b
$ dd if=.hg/store/data/a.i of=start bs=1 count=20 2>/dev/null
$ cat start b > .hg/store/data/a.i
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
a@1: broken revlog! (index data/a.i is corrupted)
warning: orphan revlog 'data/a.i'
1 files, 2 changesets, 0 total revisions
1 warnings encountered!
1 integrity errors encountered!
(first damaged changeset appears to be 1)
[1]
$ cd ..
test revlog format 0
$ revlog-formatv0.py
$ cd formatv0
$ hg verify
repository uses revlog format 0
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
$ cd ..