view tests/test-generaldelta.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.

Check whether size of generaldelta revlog is not bigger than its
regular equivalent. Test would fail if generaldelta was naive
implementation of parentdelta: third manifest revision would be fully
inserted due to big distance from its paren revision (zero).

  $ hg init repo --config format.generaldelta=no --config format.usegeneraldelta=no
  $ cd repo
  $ echo foo > foo
  $ echo bar > bar
  $ echo baz > baz
  $ hg commit -q -Am boo
  $ hg clone --pull . ../gdrepo -q --config format.generaldelta=yes
  $ for r in 1 2 3; do
  >   echo $r > foo
  >   hg commit -q -m $r
  >   hg up -q -r 0
  >   hg pull . -q -r $r -R ../gdrepo
  > done

  $ cd ..
  >>> from __future__ import print_function
  >>> import os
  >>> regsize = os.stat("repo/.hg/store/00manifest.i").st_size
  >>> gdsize = os.stat("gdrepo/.hg/store/00manifest.i").st_size
  >>> if regsize < gdsize:
  ...     print('generaldata increased size of manifest')

Verify rev reordering doesnt create invalid bundles (issue4462)
This requires a commit tree that when pulled will reorder manifest revs such
that the second manifest to create a file rev will be ordered before the first
manifest to create that file rev. We also need to do a partial pull to ensure
reordering happens. At the end we verify the linkrev points at the earliest
commit.

  $ hg init server --config format.generaldelta=True
  $ cd server
  $ touch a
  $ hg commit -Aqm a
  $ echo x > x
  $ echo y > y
  $ hg commit -Aqm xy
  $ hg up -q '.^'
  $ echo x > x
  $ echo z > z
  $ hg commit -Aqm xz
  $ hg up -q 1
  $ echo b > b
  $ hg commit -Aqm b
  $ hg merge -q 2
  $ hg commit -Aqm merge
  $ echo c > c
  $ hg commit -Aqm c
  $ hg log -G -T '{rev} {shortest(node)} {desc}'
  @  5 ebb8 c
  |
  o    4 baf7 merge
  |\
  | o  3 a129 b
  | |
  o |  2 958c xz
  | |
  | o  1 f00c xy
  |/
  o  0 3903 a
  
  $ cd ..
  $ hg init client --config format.generaldelta=false --config format.usegeneraldelta=false
  $ cd client
  $ hg pull -q ../server -r 4
  $ hg debugindex x
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0       3      0       1 1406e7411862 000000000000 000000000000

  $ cd ..

Test "usegeneraldelta" config
(repo are general delta, but incoming bundle are not re-deltafied)

delta coming from the server base delta server are not recompressed.
(also include the aggressive version for comparison)

  $ hg clone repo --pull --config format.usegeneraldelta=1 usegd
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 6 changes to 3 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg clone repo --pull --config format.generaldelta=1 full
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 6 changes to 3 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -R repo debugindex -m
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0     104      0       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      0       2 134fdc6fd680 cef96823c800 000000000000
       3       218     104      3       3 723508934dad cef96823c800 000000000000
  $ hg -R usegd debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0     104     -1       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      1       2 134fdc6fd680 cef96823c800 000000000000
       3       218      57      0       3 723508934dad cef96823c800 000000000000
  $ hg -R full debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0     104     -1       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      0       2 134fdc6fd680 cef96823c800 000000000000
       3       218      57      0       3 723508934dad cef96823c800 000000000000

Test format.aggressivemergedeltas

  $ hg init --config format.generaldelta=1 aggressive
  $ cd aggressive
  $ cat << EOF >> .hg/hgrc
  > [format]
  > generaldelta = 1
  > EOF
  $ touch a b c d e
  $ hg commit -Aqm side1
  $ hg up -q null
  $ touch x y
  $ hg commit -Aqm side2

- Verify non-aggressive merge uses p1 (commit 1) as delta parent
  $ hg merge -q 0
  $ hg commit -q -m merge
  $ hg debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      59     -1       0 8dde941edb6e 000000000000 000000000000
       1        59      61      0       1 315c023f341d 000000000000 000000000000
       2       120      65      1       2 2ab389a983eb 315c023f341d 8dde941edb6e

  $ hg strip -q -r . --config extensions.strip=

- Verify aggressive merge uses p2 (commit 0) as delta parent
  $ hg up -q -C 1
  $ hg merge -q 0
  $ hg commit -q -m merge --config format.aggressivemergedeltas=True
  $ hg debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      59     -1       0 8dde941edb6e 000000000000 000000000000
       1        59      61      0       1 315c023f341d 000000000000 000000000000
       2       120      62      0       2 2ab389a983eb 315c023f341d 8dde941edb6e

Test that strip bundle use bundle2
  $ hg --config extensions.strip= strip .
  0 files updated, 0 files merged, 5 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/aggressive/.hg/strip-backup/1c5d4dc9a8b8-6c68e60c-backup.hg (glob)
  $ hg debugbundle .hg/strip-backup/*
  Stream params: sortdict([('Compression', 'BZ')])
  changegroup -- "sortdict([('version', '02'), ('nbchanges', '1')])"
      1c5d4dc9a8b8d6e1750966d343e94db665e7a1e9

  $ cd ..