view tests/test-sparse.t @ 36820:f33a87cf60cc

xdiff: add a preprocessing step that trims files

xdiff has a `xdl_trim_ends` step that removes common lines, unmatchable
lines. That is in theory good, but happens too late - after splitting,
hashing, and adjusting the hash values so they are unique. Those splitting,
hashing and adjusting hash values steps could have noticeable overhead.

Diffing two large files with minor (one-line-ish) changes are not uncommon.
In that case, the raw performance of those preparation steps seriously
matter. Even allocating an O(N) array and storing line offsets to it is
expensive.  Therefore my previous attempts [1] [2] cannot be good enough
since they do not remove the O(N) array assignment.

This patch adds a preprocessing step - `xdl_trim_files` that runs before
other preprocessing steps. It counts common prefix and suffix and lines in
them (needed for displaying line number), without doing anything else.

Testing with a crafted large (169MB) file, with minor change:

```
  open('a','w').write(''.join('%s\n' % (i % 100000) for i in xrange(30000000) if i != 6000000))
  open('b','w').write(''.join('%s\n' % (i % 100000) for i in xrange(30000000) if i != 6003000))
```

Running xdiff by a simple binary [3], this patch improves the xdiff perf by
more than 10x for the above case:

```
  # xdiff before this patch
  2.41s user 1.13s system 98% cpu 3.592 total
  # xdiff after this patch
  0.14s user 0.16s system 98% cpu 0.309 total
  # gnu diffutils
  0.12s user 0.15s system 98% cpu 0.272 total
  # (best of 20 runs)
```

It's still slightly slower than GNU diffutils. But it's pretty close now.

Testing with real repo data:

For the whole repo, this patch makes xdiff 25% faster:

```
  # hg perfbdiff --count 100 --alldata -c d334afc585e2 --blocks [--xdiff]
  # xdiff, after
  ! wall 0.058861 comb 0.050000 user 0.050000 sys 0.000000 (best of 100)
  # xdiff, before
  ! wall 0.077816 comb 0.080000 user 0.080000 sys 0.000000 (best of 91)
  # bdiff
  ! wall 0.117473 comb 0.120000 user 0.120000 sys 0.000000 (best of 67)
```

For files that are long (ex. commands.py), the speedup is more than 3x, very
significant:

```
  # hg perfbdiff --count 3000 --blocks commands.py.i 1 [--xdiff]
  # xdiff, after
  ! wall 0.690583 comb 0.690000 user 0.690000 sys 0.000000 (best of 12)
  # xdiff, before
  ! wall 2.240361 comb 2.210000 user 2.210000 sys 0.000000 (best of 4)
  # bdiff
  ! wall 2.469852 comb 2.440000 user 2.440000 sys 0.000000 (best of 4)
```

[1]: https://phab.mercurial-scm.org/D2631
[2]: https://phab.mercurial-scm.org/D2634
[3]:

```
// Code to run xdiff from command line. No proper error handling.
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "mercurial/thirdparty/xdiff/xdiff.h"
#define ensure(x) if (!(x)) exit(255);
mmfile_t readfile(const char *path) {
  struct stat st; int fd = open(path, O_RDONLY);
  fstat(fd, &st); mmfile_t file = { malloc(st.st_size), st.st_size };
  ensure(read(fd, file.ptr, st.st_size) == st.st_size); close(fd);
  return file;
}
int main(int argc, char const *argv[]) {
  mmfile_t a = readfile(argv[1]), b = readfile(argv[2]);
  xpparam_t xpp = {0}; xdemitconf_t xecfg = {0}; xdemitcb_t ecb = {0};
  xdl_diff(&a, &b, &xpp, &xecfg, &ecb);
  return 0;
}
```

Differential Revision: https://phab.mercurial-scm.org/D2686

test sparse

  $ hg init myrepo
  $ cd myrepo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=
  > strip=
  > EOF

  $ echo a > show
  $ echo x > hide
  $ hg ci -Aqm 'initial'

  $ echo b > show
  $ echo y > hide
  $ echo aa > show2
  $ echo xx > hide2
  $ hg ci -Aqm 'two'

Verify basic --include

  $ hg up -q 0
  $ hg debugsparse --include 'hide'
  $ ls
  hide

Absolute paths outside the repo should just be rejected

#if no-windows
  $ hg debugsparse --include /foo/bar
  abort: paths cannot be absolute
  [255]
  $ hg debugsparse --include '$TESTTMP/myrepo/hide'

  $ hg debugsparse --include '/root'
  abort: paths cannot be absolute
  [255]
#else
TODO: See if this can be made to fail the same way as on Unix
  $ hg debugsparse --include /c/foo/bar
  abort: paths cannot be absolute
  [255]
  $ hg debugsparse --include '$TESTTMP/myrepo/hide'

  $ hg debugsparse --include '/c/root'
  abort: paths cannot be absolute
  [255]
#endif

Paths should be treated as cwd-relative, not repo-root-relative
  $ mkdir subdir && cd subdir
  $ hg debugsparse --include path
  $ hg debugsparse
  [include]
  $TESTTMP/myrepo/hide
  hide
  subdir/path
  
  $ cd ..
  $ echo hello > subdir/file2.ext
  $ cd subdir
  $ hg debugsparse --include '**.ext'  # let us test globs
  $ hg debugsparse --include 'path:abspath'  # and a path: pattern
  $ cd ..
  $ hg debugsparse
  [include]
  $TESTTMP/myrepo/hide
  hide
  path:abspath
  subdir/**.ext
  subdir/path
  
  $ rm -rf subdir

Verify commiting while sparse includes other files

  $ echo z > hide
  $ hg ci -Aqm 'edit hide'
  $ ls
  hide
  $ hg manifest
  hide
  show

Verify --reset brings files back

  $ hg debugsparse --reset
  $ ls
  hide
  show
  $ cat hide
  z
  $ cat show
  a

Verify 'hg debugsparse' default output

  $ hg up -q null
  $ hg debugsparse --include 'show*'

  $ hg debugsparse
  [include]
  show*
  
Verify update only writes included files

  $ hg up -q 0
  $ ls
  show

  $ hg up -q 1
  $ ls
  show
  show2

Verify status only shows included files

  $ touch hide
  $ touch hide3
  $ echo c > show
  $ hg status
  M show

Adding an excluded file should fail

  $ hg add hide3
  abort: cannot add 'hide3' - it is outside the sparse checkout
  (include file with `hg debugsparse --include <pattern>` or use `hg add -s <file>` to include file directory while adding)
  [255]

But adding a truly excluded file shouldn't count

  $ hg add hide3 -X hide3

Verify deleting sparseness while a file has changes fails

  $ hg debugsparse --delete 'show*'
  pending changes to 'hide'
  abort: cannot change sparseness due to pending changes (delete the files or use --force to bring them back dirty)
  [255]

Verify deleting sparseness with --force brings back files

  $ hg debugsparse --delete -f 'show*'
  pending changes to 'hide'
  $ ls
  hide
  hide2
  hide3
  show
  show2
  $ hg st
  M hide
  M show
  ? hide3

Verify editing sparseness fails if pending changes

  $ hg debugsparse --include 'show*'
  pending changes to 'hide'
  abort: could not update sparseness due to pending changes
  [255]

Verify adding sparseness hides files

  $ hg debugsparse --exclude -f 'hide*'
  pending changes to 'hide'
  $ ls
  hide
  hide3
  show
  show2
  $ hg st
  M show

  $ hg up -qC .
TODO: add an option to purge to also purge files outside the sparse config?
  $ hg purge --all --config extensions.purge=
  $ ls
  hide
  hide3
  show
  show2
For now, manually remove the files
  $ rm hide hide3

Verify rebase temporarily includes excluded files

  $ hg rebase -d 1 -r 2 --config extensions.rebase=
  rebasing 2:b91df4f39e75 "edit hide" (tip)
  temporarily included 1 file(s) in the sparse checkout for merging
  merging hide
  warning: conflicts while merging hide! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

  $ hg debugsparse
  [exclude]
  hide*
  
  Temporarily Included Files (for merge/rebase):
  hide

  $ cat hide
  <<<<<<< dest:   39278f7c08a9 - test: two
  y
  =======
  z
  >>>>>>> source: b91df4f39e75 - test: edit hide

Verify aborting a rebase cleans up temporary files

  $ hg rebase --abort --config extensions.rebase=
  cleaned up 1 temporarily added file(s) from the sparse checkout
  rebase aborted
  $ rm hide.orig

  $ ls
  show
  show2

Verify merge fails if merging excluded files

  $ hg up -q 1
  $ hg merge -r 2
  temporarily included 1 file(s) in the sparse checkout for merging
  merging hide
  warning: conflicts while merging hide! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]
  $ hg debugsparse
  [exclude]
  hide*
  
  Temporarily Included Files (for merge/rebase):
  hide

  $ hg up -C .
  cleaned up 1 temporarily added file(s) from the sparse checkout
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg debugsparse
  [exclude]
  hide*
  

Verify strip -k resets dirstate correctly

  $ hg status
  $ hg debugsparse
  [exclude]
  hide*
  
  $ hg log -r . -T '{rev}\n' --stat
  1
   hide  |  2 +-
   hide2 |  1 +
   show  |  2 +-
   show2 |  1 +
   4 files changed, 4 insertions(+), 2 deletions(-)
  
  $ hg strip -r . -k
  saved backup bundle to $TESTTMP/myrepo/.hg/strip-backup/39278f7c08a9-ce59e002-backup.hg
  $ hg status
  M show
  ? show2

Verify rebase succeeds if all changed files are in sparse checkout

  $ hg commit -Aqm "add show2"
  $ hg rebase -d 1 --config extensions.rebase=
  rebasing 2:bdde55290160 "add show2" (tip)
  saved backup bundle to $TESTTMP/myrepo/.hg/strip-backup/bdde55290160-216ed9c6-rebase.hg

Verify log --sparse only shows commits that affect the sparse checkout

  $ hg log -T '{rev} '
  2 1 0  (no-eol)
  $ hg log --sparse -T '{rev} '
  2 0  (no-eol)

Test status on a file in a subdir

  $ mkdir -p dir1/dir2
  $ touch dir1/dir2/file
  $ hg debugsparse -I dir1/dir2
  $ hg status
  ? dir1/dir2/file

Mix files and subdirectories, both "glob:" and unprefixed

  $ hg debugsparse --reset
  $ touch dir1/notshown
  $ hg commit -A dir1/notshown -m "notshown"
  $ hg debugsparse --include 'dir1/dir2'
  $ $PYTHON $TESTDIR/list-tree.py . | egrep -v '\.[\/]\.hg'
  ./
  ./dir1/
  ./dir1/dir2/
  ./dir1/dir2/file
  ./hide.orig
  $ hg debugsparse --delete 'dir1/dir2'
  $ hg debugsparse --include 'glob:dir1/dir2'
  $ $PYTHON $TESTDIR/list-tree.py . | egrep -v '\.[\/]\.hg'
  ./
  ./dir1/
  ./dir1/dir2/
  ./dir1/dir2/file
  ./hide.orig

Test that add -s adds dirs to sparse profile

  $ hg debugsparse --reset
  $ hg debugsparse --include empty
  $ hg debugsparse
  [include]
  empty
  

  $ mkdir add
  $ touch add/foo
  $ touch add/bar
  $ hg add add/foo
  abort: cannot add 'add/foo' - it is outside the sparse checkout
  (include file with `hg debugsparse --include <pattern>` or use `hg add -s <file>` to include file directory while adding)
  [255]
  $ hg add -s add/foo
  $ hg st
  A add/foo
  ? add/bar
  $ hg debugsparse
  [include]
  add
  empty
  
  $ hg add -s add/*
  add/foo already tracked!
  $ hg st
  A add/bar
  A add/foo
  $ hg debugsparse
  [include]
  add
  empty
  

  $ cd ..

Test non-sparse repos work while sparse is loaded
  $ hg init sparserepo
  $ hg init nonsparserepo
  $ cd sparserepo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=
  > EOF
  $ cd ../nonsparserepo
  $ echo x > x && hg add x && hg commit -qAm x
  $ cd ../sparserepo
  $ hg clone ../nonsparserepo ../nonsparserepo2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test debugrebuilddirstate
  $ cd ../sparserepo
  $ touch included
  $ touch excluded
  $ hg add included excluded
  $ hg commit -m 'a commit' -q
  $ cp .hg/dirstate ../dirstateboth
  $ hg debugsparse -X excluded
  $ cp ../dirstateboth .hg/dirstate
  $ hg debugrebuilddirstate
  $ hg debugdirstate
  n   0         -1 unset               included

Test debugdirstate --minimal where file is in the parent manifest but not the
dirstate
  $ hg debugsparse -X included
  $ hg debugdirstate
  $ cp .hg/dirstate ../dirstateallexcluded
  $ hg debugsparse --reset
  $ hg debugsparse -X excluded
  $ cp ../dirstateallexcluded .hg/dirstate
  $ touch includedadded
  $ hg add includedadded
  $ hg debugdirstate --nodates
  a   0         -1 unset               includedadded
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --nodates
  n   0         -1 unset               included
  a   0         -1 * includedadded (glob)

Test debugdirstate --minimal where a file is not in parent manifest
but in the dirstate. This should take into account excluded files in the
manifest
  $ cp ../dirstateboth .hg/dirstate
  $ touch includedadded
  $ hg add includedadded
  $ touch excludednomanifest
  $ hg add excludednomanifest
  $ cp .hg/dirstate ../moreexcluded
  $ hg forget excludednomanifest
  $ rm excludednomanifest
  $ hg debugsparse -X excludednomanifest
  $ cp ../moreexcluded .hg/dirstate
  $ hg manifest
  excluded
  included
We have files in the dirstate that are included and excluded. Some are in the
manifest and some are not.
  $ hg debugdirstate --nodates
  n 644          0 * excluded (glob)
  a   0         -1 * excludednomanifest (glob)
  n 644          0 * included (glob)
  a   0         -1 * includedadded (glob)
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --nodates
  n 644          0 * included (glob)
  a   0         -1 * includedadded (glob)