view tests/test-win32text.t @ 36672:9e7b14caf67f

xdiff: remove patience and histogram diff algorithms

Patience diff is the normal diff algorithm, plus some greediness that
unconditionally matches common common unique lines.  That means it is easy to
construct cases to let it generate suboptimal result, like:

```
open('a', 'w').write('\n'.join(list('a' + 'x' * 300 + 'u' + 'x' * 700 + 'a\n')))
open('b', 'w').write('\n'.join(list('b' + 'x' * 700 + 'u' + 'x' * 300 + 'b\n')))
```

Patience diff has been advertised as being able to generate better results for
some C code changes. However, the more scientific way to do that is the
indention heuristic [1].

Since patience diff could generate suboptimal result more easily and its
"better" diff feature could be replaced by the new indention heuristic, let's
just remove it and its variant histogram diff to simplify the code.

[1]: https://github.com/git/git/commit/433860f3d0beb0c6f205290bd16cda413148f098

Test Plan:
`gcc -fPIC *.c --shared -o xdiff.so` still builds.

Differential Revision: https://phab.mercurial-scm.org/D2573

  $ hg init t
  $ cd t
  $ cat > unix2dos.py <<EOF
  > import sys
  > 
  > for path in sys.argv[1:]:
  >     data = open(path, 'rb').read()
  >     data = data.replace(b'\n', b'\r\n')
  >     open(path, 'wb').write(data)
  > EOF
  $ echo '[hooks]' >> .hg/hgrc
  $ echo 'pretxncommit.crlf = python:hgext.win32text.forbidcrlf' >> .hg/hgrc
  $ echo 'pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf' >> .hg/hgrc
  $ cat .hg/hgrc
  [hooks]
  pretxncommit.crlf = python:hgext.win32text.forbidcrlf
  pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf

  $ echo hello > f
  $ hg add f

commit should succeed

  $ hg ci -m 1

  $ hg clone . ../zoz
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cp .hg/hgrc ../zoz/.hg
  $ $PYTHON unix2dos.py f

commit should fail

  $ hg ci -m 2.1
  attempt to commit or push text file(s) using CRLF line endings
  in f583ea08d42a: f
  transaction abort!
  rollback completed
  abort: pretxncommit.crlf hook failed
  [255]

  $ mv .hg/hgrc .hg/hgrc.bak

commits should succeed

  $ hg ci -m 2
  $ hg cp f g
  $ hg ci -m 2.2

push should fail

  $ hg push ../zoz
  pushing to ../zoz
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  attempt to commit or push text file(s) using CRLF line endings
  in bc2d09796734: g
  in b1aa5cde7ff4: f
  
  To prevent this mistake in your local repository,
  add to Mercurial.ini or .hg/hgrc:
  
  [hooks]
  pretxncommit.crlf = python:hgext.win32text.forbidcrlf
  
  and also consider adding:
  
  [extensions]
  win32text =
  [encode]
  ** = cleverencode:
  [decode]
  ** = cleverdecode:
  transaction abort!
  rollback completed
  abort: pretxnchangegroup.crlf hook failed
  [255]

  $ mv .hg/hgrc.bak .hg/hgrc
  $ echo hello > f
  $ hg rm g

commit should succeed

  $ hg ci -m 2.3

push should succeed

  $ hg push ../zoz
  pushing to ../zoz
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files

and now for something completely different

  $ mkdir d
  $ echo hello > d/f2
  $ $PYTHON unix2dos.py d/f2
  $ hg add d/f2
  $ hg ci -m 3
  attempt to commit or push text file(s) using CRLF line endings
  in 053ba1a3035a: d/f2
  transaction abort!
  rollback completed
  abort: pretxncommit.crlf hook failed
  [255]
  $ hg revert -a
  forgetting d/f2
  $ rm d/f2

  $ hg rem f
  $ hg ci -m 4

  $ $PYTHON -c 'open("bin", "wb").write(b"hello\x00\x0D\x0A")'
  $ hg add bin
  $ hg ci -m 5
  $ hg log -v
  changeset:   5:f0b1c8d75fce
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       bin
  description:
  5
  
  
  changeset:   4:77796dbcd4ad
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  4
  
  
  changeset:   3:7c1b5430b350
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f g
  description:
  2.3
  
  
  changeset:   2:bc2d09796734
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       g
  description:
  2.2
  
  
  changeset:   1:b1aa5cde7ff4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  2
  
  
  changeset:   0:fcf06d5c4e1d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  1
  
  
  $ hg clone . dupe
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ for x in a b c d; do echo content > dupe/$x; done
  $ hg -R dupe add
  adding dupe/a
  adding dupe/b
  adding dupe/c
  adding dupe/d
  $ $PYTHON unix2dos.py dupe/b dupe/c dupe/d
  $ hg -R dupe ci -m a dupe/a
  $ hg -R dupe ci -m b/c dupe/[bc]
  $ hg -R dupe ci -m d dupe/d
  $ hg -R dupe log -v
  changeset:   8:67ac5962ab43
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       d
  description:
  d
  
  
  changeset:   7:68c127d1834e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       b c
  description:
  b/c
  
  
  changeset:   6:adbf8bf7f31d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  a
  
  
  changeset:   5:f0b1c8d75fce
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       bin
  description:
  5
  
  
  changeset:   4:77796dbcd4ad
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  4
  
  
  changeset:   3:7c1b5430b350
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f g
  description:
  2.3
  
  
  changeset:   2:bc2d09796734
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       g
  description:
  2.2
  
  
  changeset:   1:b1aa5cde7ff4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  2
  
  
  changeset:   0:fcf06d5c4e1d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  1
  
  
  $ hg pull dupe
  pulling from dupe
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 4 changes to 4 files
  attempt to commit or push text file(s) using CRLF line endings
  in 67ac5962ab43: d
  in 68c127d1834e: b
  in 68c127d1834e: c
  
  To prevent this mistake in your local repository,
  add to Mercurial.ini or .hg/hgrc:
  
  [hooks]
  pretxncommit.crlf = python:hgext.win32text.forbidcrlf
  
  and also consider adding:
  
  [extensions]
  win32text =
  [encode]
  ** = cleverencode:
  [decode]
  ** = cleverdecode:
  transaction abort!
  rollback completed
  abort: pretxnchangegroup.crlf hook failed
  [255]

  $ hg log -v
  changeset:   5:f0b1c8d75fce
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       bin
  description:
  5
  
  
  changeset:   4:77796dbcd4ad
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  4
  
  
  changeset:   3:7c1b5430b350
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f g
  description:
  2.3
  
  
  changeset:   2:bc2d09796734
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       g
  description:
  2.2
  
  
  changeset:   1:b1aa5cde7ff4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  2
  
  
  changeset:   0:fcf06d5c4e1d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       f
  description:
  1
  
  
  $ rm .hg/hgrc
  $ (echo some; echo text) > f3
  $ $PYTHON -c 'open("f4.bat", "wb").write(b"rem empty\x0D\x0A")'
  $ hg add f3 f4.bat
  $ hg ci -m 6
  $ cat bin
  hello\x00\r (esc)
  $ cat f3
  some
  text
  $ cat f4.bat
  rem empty\r (esc)

  $ echo '[extensions]' >> .hg/hgrc
  $ echo 'win32text = ' >> .hg/hgrc
  $ echo '[decode]' >> .hg/hgrc
  $ echo '** = cleverdecode:' >> .hg/hgrc
  $ echo '[encode]' >> .hg/hgrc
  $ echo '** = cleverencode:' >> .hg/hgrc
  $ cat .hg/hgrc
  [extensions]
  win32text = 
  [decode]
  ** = cleverdecode:
  [encode]
  ** = cleverencode:

Trigger deprecation warning:

  $ hg id -t
  win32text is deprecated: https://mercurial-scm.org/wiki/Win32TextExtension
  tip

Disable warning:

  $ echo '[win32text]' >> .hg/hgrc
  $ echo 'warn = no' >> .hg/hgrc
  $ hg id -t
  tip

  $ rm f3 f4.bat bin
  $ hg co -C
  WARNING: f4.bat already has CRLF line endings
  and does not need EOL conversion by the win32text plugin.
  Before your next commit, please reconsider your encode/decode settings in 
  Mercurial.ini or $TESTTMP/t/.hg/hgrc.
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat bin
  hello\x00\r (esc)
  $ cat f3
  some\r (esc)
  text\r (esc)
  $ cat f4.bat
  rem empty\r (esc)

  $ $PYTHON -c 'open("f5.sh", "wb").write(b"# empty\x0D\x0A")'
  $ hg add f5.sh
  $ hg ci -m 7
  $ cat f5.sh
  # empty\r (esc)
  $ hg cat f5.sh
  # empty
  $ echo '% just linefeed' > linefeed
  $ hg ci -qAm 8 linefeed
  $ cat linefeed
  % just linefeed
  $ hg cat linefeed
  % just linefeed
  $ hg st -q
  $ hg revert -a linefeed
  no changes needed to linefeed
  $ cat linefeed
  % just linefeed
  $ hg st -q
  $ echo modified >> linefeed
  $ hg st -q
  M linefeed
  $ hg revert -a
  reverting linefeed
  $ hg st -q
  $ cat linefeed
  % just linefeed\r (esc)

  $ cd ..