view tests/test-extdiff.t @ 30442:41a8106789ca

util: implement zstd compression engine

Now that zstd is vendored and being built (in some configurations), we
can implement a compression engine for zstd!

The zstd engine is a little different from existing engines. Because
it may not always be present, we have to defer load the module in case
importing it fails. We facilitate this via a cached property that holds
a reference to the module or None. The "available" method is
implemented to reflect reality.

The zstd engine declares its ability to handle bundles using the
"zstd" human name and the "ZS" internal name. The latter was chosen
because internal names are 2 characters (by only convention I think)
and "ZS" seems reasonable.

The engine, like others, supports specifying the compression level.
However, there are no consumers of this API that yet pass in that
argument. I have plans to change that, so stay tuned.

Since all we need to do to support bundle generation with a new
compression engine is implement and register the compression engine,
bundle generation with zstd "just works!" Tests demonstrating this
have been added.

How does performance of zstd for bundle generation compare? On the
mozilla-unified repo, `hg bundle --all -t <engine>-v2` yields the
following on my i7-6700K on Linux:

engine        CPU time     bundle size   vs orig size   throughput
none            97.0s     4,054,405,584     100.0%       41.8 MB/s
bzip2 (l=9)    393.6s       975,343,098      24.0%       10.3 MB/s
gzip (l=6)     184.0s     1,140,533,074      28.1%       22.0 MB/s
zstd (l=1)     108.2s     1,119,434,718      27.6%       37.5 MB/s
zstd (l=2)     111.3s     1,078,328,002      26.6%       36.4 MB/s
zstd (l=3)     113.7s     1,011,823,727      25.0%       35.7 MB/s
zstd (l=4)     116.0s     1,008,965,888      24.9%       35.0 MB/s
zstd (l=5)     121.0s       977,203,148      24.1%       33.5 MB/s
zstd (l=6)     131.7s       927,360,198      22.9%       30.8 MB/s
zstd (l=7)     139.0s       912,808,505      22.5%       29.2 MB/s
zstd (l=12)    198.1s       854,527,714      21.1%       20.5 MB/s
zstd (l=18)    681.6s       789,750,690      19.5%        5.9 MB/s

On compression, zstd for bundle generation delivers:

* better compression than gzip with significantly less CPU utilization
* better than bzip2 compression ratios while still being significantly
  faster than gzip
* ability to aggressively tune compression level to achieve
  significantly smaller bundles

That last point is important. With clone bundles, a server can
pre-generate a bundle file, upload it to a static file server, and
redirect clients to transparently download it during clone. The server
could choose to produce a zstd bundle with the highest compression
settings possible. This would take a very long time - a magnitude
longer than a typical zstd bundle generation - but the result would
be hundreds of megabytes smaller! For the clone volume we do at
Mozilla, this could translate to petabytes of bandwidth savings
per year and faster clones (due to smaller transfer size).

I don't have detailed numbers to report on decompression. However,
zstd decompression is fast: >1 GB/s output throughput on this machine,
even through the Python bindings. And it can do that regardless of the
compression level of the input. By the time you have enough data to
worry about overhead of decompression, you have plenty of other things
to worry about performance wise.

zstd is wins all around. I can't wait to implement support for it
on the wire protocol and in revlogs.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "extdiff=" >> $HGRCPATH

  $ hg init a
  $ cd a
  $ echo a > a
  $ echo b > b
  $ hg add
  adding a
  adding b

Should diff cloned directories:

  $ hg extdiff -o -r $opt
  Only in a: a
  Only in a: b
  [1]

  $ cat <<EOF >> $HGRCPATH
  > [extdiff]
  > cmd.falabala = echo
  > opts.falabala = diffing
  > cmd.edspace = echo
  > opts.edspace = "name  <[e-mail]>"
  > EOF

  $ hg falabala
  diffing a.000000000000 a
  [1]

  $ hg help falabala
  hg falabala [OPTION]... [FILE]...
  
  use external program to diff repository (or selected files)
  
      Show differences between revisions for the specified files, using the
      following program:
  
        'echo'
  
      When two revision arguments are given, then changes are shown between
      those revisions. If only one revision is specified then that revision is
      compared to the working directory, and, when no revisions are specified,
      the working directory files are compared to its parent.
  
  options ([+] can be repeated):
  
   -o --option OPT [+]      pass option to comparison program
   -r --rev REV [+]         revision
   -c --change REV          change made by revision
      --patch               compare patches for two revisions
   -I --include PATTERN [+] include names matching the given patterns
   -X --exclude PATTERN [+] exclude names matching the given patterns
   -S --subrepos            recurse into subrepositories
  
  (some details hidden, use --verbose to show complete help)

  $ hg ci -d '0 0' -mtest1

  $ echo b >> a
  $ hg ci -d '1 0' -mtest2

Should diff cloned files directly:

#if windows
  $ hg falabala -r 0:1
  diffing "*\\extdiff.*\\a.8a5febb7f867\\a" "a.34eed99112ab\\a" (glob)
  [1]
#else
  $ hg falabala -r 0:1
  diffing */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]
#endif

Specifying an empty revision should abort.

  $ hg extdiff -p diff --patch --rev 'ancestor()' --rev 1
  abort: empty revision on one side of range
  [255]

Test diff during merge:

  $ hg update -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo c >> c
  $ hg add c
  $ hg ci -m "new branch" -d '1 0'
  created new head
  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Should diff cloned file against wc file:

#if windows
  $ hg falabala
  diffing "*\\extdiff.*\\a.2a13a4d2da36\\a" "*\\a\\a" (glob)
  [1]
#else
  $ hg falabala
  diffing */extdiff.*/a.2a13a4d2da36/a */a/a (glob)
  [1]
#endif


Test --change option:

  $ hg ci -d '2 0' -mtest3
#if windows
  $ hg falabala -c 1
  diffing "*\\extdiff.*\\a.8a5febb7f867\\a" "a.34eed99112ab\\a" (glob)
  [1]
#else
  $ hg falabala -c 1
  diffing */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]
#endif

Check diff are made from the first parent:

#if windows
  $ hg falabala -c 3 || echo "diff-like tools yield a non-zero exit code"
  diffing "*\\extdiff.*\\a.2a13a4d2da36\\a" "a.46c0e4daeb72\\a" (glob)
  diff-like tools yield a non-zero exit code
#else
  $ hg falabala -c 3 || echo "diff-like tools yield a non-zero exit code"
  diffing */extdiff.*/a.2a13a4d2da36/a a.46c0e4daeb72/a (glob)
  diff-like tools yield a non-zero exit code
#endif

issue3153: ensure using extdiff with removed subrepos doesn't crash:

  $ hg init suba
  $ cd suba
  $ echo suba > suba
  $ hg add
  adding suba
  $ hg ci -m "adding suba file"
  $ cd ..
  $ echo suba=suba > .hgsub
  $ hg add
  adding .hgsub
  $ hg ci -Sm "adding subrepo"
  $ echo > .hgsub
  $ hg ci -m "removing subrepo"
  $ hg falabala -r 4 -r 5 -S
  diffing a.398e36faf9c6 a.5ab95fb166c4
  [1]

issue4463: usage of command line configuration without additional quoting

  $ cat <<EOF >> $HGRCPATH
  > [extdiff]
  > cmd.4463a = echo
  > opts.4463a = a-naked 'single quoted' "double quoted"
  > 4463b = echo b-naked 'single quoted' "double quoted"
  > echo =
  > EOF
  $ hg update -q -C 0
  $ echo a >> a
#if windows
  $ hg --debug 4463a | grep '^running'
  running 'echo a-naked \'single quoted\' "double quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug 4463b | grep '^running'
  running 'echo b-naked \'single quoted\' "double quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug echo | grep '^running'
  running '*echo* "*\\a" "*\\a"' in */extdiff.* (glob)
#else
  $ hg --debug 4463a | grep '^running'
  running 'echo a-naked \'single quoted\' "double quoted" */a $TESTTMP/a/a' in */extdiff.* (glob)
  $ hg --debug 4463b | grep '^running'
  running 'echo b-naked \'single quoted\' "double quoted" */a $TESTTMP/a/a' in */extdiff.* (glob)
  $ hg --debug echo | grep '^running'
  running '*echo */a $TESTTMP/a/a' in */extdiff.* (glob)
#endif

(getting options from other than extdiff section)

  $ cat <<EOF >> $HGRCPATH
  > [extdiff]
  > # using diff-tools diffargs
  > 4463b2 = echo
  > # using merge-tools diffargs
  > 4463b3 = echo
  > # no diffargs
  > 4463b4 = echo
  > [diff-tools]
  > 4463b2.diffargs = b2-naked 'single quoted' "double quoted"
  > [merge-tools]
  > 4463b3.diffargs = b3-naked 'single quoted' "double quoted"
  > EOF
#if windows
  $ hg --debug 4463b2 | grep '^running'
  running 'echo b2-naked \'single quoted\' "double quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug 4463b3 | grep '^running'
  running 'echo b3-naked \'single quoted\' "double quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug 4463b4 | grep '^running'
  running 'echo "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug 4463b4 --option b4-naked --option 'being quoted' | grep '^running'
  running 'echo b4-naked "being quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
  $ hg --debug extdiff -p echo --option echo-naked --option 'being quoted' | grep '^running'
  running 'echo echo-naked "being quoted" "*\\a" "*\\a"' in */extdiff.* (glob)
#else
  $ hg --debug 4463b2 | grep '^running'
  running 'echo b2-naked \'single quoted\' "double quoted" */a $TESTTMP/a/a' in */extdiff.* (glob)
  $ hg --debug 4463b3 | grep '^running'
  running 'echo b3-naked \'single quoted\' "double quoted" */a $TESTTMP/a/a' in */extdiff.* (glob)
  $ hg --debug 4463b4 | grep '^running'
  running 'echo */a $TESTTMP/a/a' in */extdiff.* (glob)
  $ hg --debug 4463b4 --option b4-naked --option 'being quoted' | grep '^running'
  running "echo b4-naked 'being quoted' */a $TESTTMP/a/a" in */extdiff.* (glob)
  $ hg --debug extdiff -p echo --option echo-naked --option 'being quoted' | grep '^running'
  running "echo echo-naked 'being quoted' */a $TESTTMP/a/a" in */extdiff.* (glob)
#endif

  $ touch 'sp ace'
  $ hg add 'sp ace'
  $ hg ci -m 'sp ace'
  created new head
  $ echo > 'sp ace'

Test pre-72a89cf86fcd backward compatibility with half-baked manual quoting

  $ cat <<EOF >> $HGRCPATH
  > [extdiff]
  > odd =
  > [merge-tools]
  > odd.diffargs = --foo='\$clabel' '\$clabel' "--bar=\$clabel" "\$clabel"
  > odd.executable = echo
  > EOF
#if windows
TODO
#else
  $ hg --debug odd | grep '^running'
  running "*/echo --foo='sp ace' 'sp ace' --bar='sp ace' 'sp ace'" in * (glob)
#endif

Empty argument must be quoted

  $ cat <<EOF >> $HGRCPATH
  > [extdiff]
  > kdiff3 = echo
  > [merge-tools]
  > kdiff3.diffargs=--L1 \$plabel1 --L2 \$clabel \$parent \$child
  > EOF
#if windows
  $ hg --debug kdiff3 -r0 | grep '^running'
  running 'echo --L1 "@0" --L2 "" a.8a5febb7f867 a' in * (glob)
#else
  $ hg --debug kdiff3 -r0 | grep '^running'
  running "echo --L1 '@0' --L2 '' a.8a5febb7f867 a" in * (glob)
#endif

#if execbit

Test extdiff of multiple files in tmp dir:

  $ hg update -C 0 > /dev/null
  $ echo changed > a
  $ echo changed > b
  $ chmod +x b

Diff in working directory, before:

  $ hg diff --git
  diff --git a/a b/a
  --- a/a
  +++ b/a
  @@ -1,1 +1,1 @@
  -a
  +changed
  diff --git a/b b/b
  old mode 100644
  new mode 100755
  --- a/b
  +++ b/b
  @@ -1,1 +1,1 @@
  -b
  +changed


Edit with extdiff -p:

Prepare custom diff/edit tool:

  $ cat > 'diff tool.py' << EOT
  > #!/usr/bin/env python
  > import time
  > time.sleep(1) # avoid unchanged-timestamp problems
  > file('a/a', 'ab').write('edited\n')
  > file('a/b', 'ab').write('edited\n')
  > EOT

  $ chmod +x 'diff tool.py'

will change to /tmp/extdiff.TMP and populate directories a.TMP and a
and start tool

  $ hg extdiff -p "`pwd`/diff tool.py"
  [1]

Diff in working directory, after:

  $ hg diff --git
  diff --git a/a b/a
  --- a/a
  +++ b/a
  @@ -1,1 +1,2 @@
  -a
  +changed
  +edited
  diff --git a/b b/b
  old mode 100644
  new mode 100755
  --- a/b
  +++ b/b
  @@ -1,1 +1,2 @@
  -b
  +changed
  +edited

Test extdiff with --option:

  $ hg extdiff -p echo -o this -c 1
  this */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

  $ hg falabala -o this -c 1
  diffing this */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

Test extdiff's handling of options with spaces in them:

  $ hg edspace -c 1
  name  <[e-mail]> */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

  $ hg extdiff -p echo -o "name  <[e-mail]>" -c 1
  name  <[e-mail]> */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

Test with revsets:

  $ hg extdif -p echo -c "rev(1)"
  */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

  $ hg extdif -p echo -r "0::1"
  */extdiff.*/a.8a5febb7f867/a a.34eed99112ab/a (glob)
  [1]

Fallback to merge-tools.tool.executable|regkey
  $ mkdir dir
  $ cat > 'dir/tool.sh' << EOF
  > #!/bin/sh
  > echo "** custom diff **"
  > EOF
  $ chmod +x dir/tool.sh
  $ tool=`pwd`/dir/tool.sh
  $ hg --debug tl --config extdiff.tl= --config merge-tools.tl.executable=$tool
  making snapshot of 2 files from rev * (glob)
    a
    b
  making snapshot of 2 files from working directory
    a
    b
  running '$TESTTMP/a/dir/tool.sh a.* a' in */extdiff.* (glob)
  ** custom diff **
  cleaning up temp directory
  [1]

  $ cd ..

#endif

#if symlink

Test symlinks handling (issue1909)

  $ hg init testsymlinks
  $ cd testsymlinks
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ echo a >> a
  $ ln -s missing linka
  $ hg add linka
  $ hg falabala -r 0 --traceback
  diffing testsymlinks.07f494440405 testsymlinks
  [1]
  $ cd ..

#endif

Test handling of non-ASCII paths in generated docstrings (issue5301)

  >>> open("u", "w").write("\xa5\xa5")
  $ U=`cat u`

  $ HGPLAIN=1 hg --config hgext.extdiff= --config extdiff.cmd.td=hi help -k xyzzy
  abort: no matches
  (try 'hg help' for a list of topics)
  [255]

  $ HGPLAIN=1 hg --config hgext.extdiff= --config extdiff.cmd.td=hi help td > /dev/null

  $ LC_MESSAGES=ja_JP.UTF-8 hg --config hgext.extdiff= --config extdiff.cmd.td=$U help -k xyzzy
  abort: no matches
  (try 'hg help' for a list of topics)
  [255]

  $ LC_MESSAGES=ja_JP.UTF-8 hg --config hgext.extdiff= --config extdiff.cmd.td=$U help td \
  > | grep "^      '"
        '\xa5\xa5'