tests/test-revert.t

mdiff: speed up showfunc for large diffs

This addresses the following issues with showfunc:

- Silly usage of regular expressions.
- Doing str.rstrip() needlessly in an inner loop.
- Doing catastrophic backtracking when trying to find a function line.

Finding function text is now at worst O(n lines in the old file), and
at best close to O(n hunks).

Given a diff like this[1]:

 src/main/antlr3/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunker.g        |      4 +-
 src/main/java/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunkerLexer.java  |      2 +-
 src/main/java/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunkerParser.java |  29189 +++++----
 3 files changed, 14741 insertions(+), 14454 deletions(-)

[1]: https://bitbucket.org/wwmm/chemicaltagger/changeset/d2bfbaecd4fc/raw

Without this change, hg log --stat --config diff.showfunc=1 takes an
absurdly long time to complete:

   CallCount    Recursive    Total(ms)   Inline(ms) module:lineno(function)
       32813            0     80.3546     40.6086   mercurial.mdiff:160(yieldhunk)
   [phone]            0     25.7227     25.7227   +<method 'match' of '_sre.SRE_Pattern' objects>
   [phone]            0     14.0221     14.0221   +<method 'rstrip' of 'str' objects>
       +1809            0      0.0009      0.0009   +mercurial.mdiff:148(contextend)
       +1809            0      0.0003      0.0003   +<len>
    65062746            0     25.7227     25.7227   <method 'match' of '_sre.SRE_Pattern' objects>
    65062763            0     14.0221     14.0221   <method 'rstrip' of 'str' objects>
         543            0      0.1631      0.1631   <zlib.decompress>
           3            0      0.0505      0.0505   <mercurial.bdiff.blocks>
       31007            0     80.4564      0.0477   mercurial.mdiff:147(_unidiff)
      +32813            0     80.3546     40.6086   +mercurial.mdiff:160(yieldhunk)
          +3            0      0.0505      0.0505   +<mercurial.bdiff.blocks>
       +3618            0      0.0022      0.0022   +mercurial.mdiff:154(contextstart)
       +5427            0      0.0013      0.0013   +<len>
          +3            0      0.0001      0.0000   +re:188(compile)
           1            0     80.8381      0.0322   mercurial.patch:1777(diffstatdata)
     +107499            0      0.0235      0.0235   +<method 'startswith' of 'str' objects>
      +31014            0     80.7820      0.0071   +mercurial.util:1284(iterlines)
          +3            0      0.0000      0.0000   +<method 'search' of '_sre.SRE_Pattern' objects>
          +4            0      0.0000      0.0000   +mercurial.patch:1783(addresult)
          +3            0      0.0000      0.0000   +<method 'group' of '_sre.SRE_Match' objects>
           6            0      0.0444      0.0283   mercurial.mdiff:12(splitnewlines)
          +6            0      0.0160      0.0160   +<method 'split' of 'str' objects>
          32            0      0.0246      0.0246   <method 'update' of '_hashlib.HASH' objects>
          11            0      0.0236      0.0236   <method 'read' of 'file' objects>
Time: real 80.880 secs (user 80.200+0.000 sys 0.380+0.000)

With this change, it's almost as fast as not using showfunc at all:

   CallCount    Recursive    Total(ms)   Inline(ms) module:lineno(function)
         543            0      0.1699      0.1699   <zlib.decompress>
           3            0      0.0501      0.0501   <mercurial.bdiff.blocks>
       32813            0      0.0415      0.0348   mercurial.mdiff:161(yieldhunk)
      +70837            0      0.0058      0.0058   +<method 'isalnum' of 'str' objects>
       +1809            0      0.0006      0.0006   +mercurial.mdiff:148(contextend)
       +1809            0      0.0002      0.0002   +<len>
           1            0      0.4879      0.0310   mercurial.patch:1777(diffstatdata)
     +107499            0      0.0230      0.0230   +<method 'startswith' of 'str' objects>
      +31014            0      0.4335      0.0065   +mercurial.util:1284(iterlines)
          +3            0      0.0000      0.0000   +<method 'search' of '_sre.SRE_Pattern' objects>
          +4            0      0.0000      0.0000   +mercurial.patch:1783(addresult)
          +1            0      0.0004      0.0000   +re:188(compile)
          32            0      0.0293      0.0293   <method 'update' of '_hashlib.HASH' objects>
           6            0      0.0427      0.0279   mercurial.mdiff:12(splitnewlines)
          +6            0      0.0147      0.0147   +<method 'split' of 'str' objects>
       31007            0      0.1169      0.0235   mercurial.mdiff:147(_unidiff)
          +3            0      0.0501      0.0501   +<mercurial.bdiff.blocks>
      +32813            0      0.0415      0.0348   +mercurial.mdiff:161(yieldhunk)
       +3618            0      0.0012      0.0012   +mercurial.mdiff:154(contextstart)
       +5427            0      0.0006      0.0006   +<len>
      107597            0      0.0230      0.0230   <method 'startswith' of 'str' objects>
          16            0      0.0213      0.0213   <mercurial.mpatch.patches>
         194            0      0.0149      0.0149   <method 'split' of 'str' objects>
Time: real 0.530 secs (user 0.450+0.000 sys 0.070+0.000)

  $ hg init repo
  $ cd repo
  $ echo 123 > a
  $ echo 123 > c
  $ echo 123 > e
  $ hg add a c e
  $ hg commit -m "first" a c e

nothing changed

  $ hg revert
  abort: no files or directories specified
  (use --all to revert all files)
  [255]
  $ hg revert --all

  $ echo 123 > b

should show b unknown

  $ hg status
  ? b
  $ echo 12 > c

should show b unknown and c modified

  $ hg status
  M c
  ? b
  $ hg add b

should show b added and c modified

  $ hg status
  M c
  A b
  $ hg rm a

should show a removed, b added and c modified

  $ hg status
  M c
  A b
  R a
  $ hg revert a

should show b added, copy saved, and c modified

  $ hg status
  M c
  A b
  $ hg revert b

should show b unknown, and c modified

  $ hg status
  M c
  ? b
  $ hg revert --no-backup c

should show unknown: b

  $ hg status
  ? b
  $ hg add b

should show b added

  $ hg status b
  A b
  $ rm b

should show b deleted

  $ hg status b
  ! b
  $ hg revert -v b
  forgetting b

should not find b

  $ hg status b
  b: No such file or directory

should show a c e

  $ ls
  a
  c
  e

should verbosely save backup to e.orig

  $ echo z > e
  $ hg revert --all -v
  saving current version of e as e.orig
  reverting e

should say no changes needed

  $ hg revert a
  no changes needed to a

should say file not managed

  $ echo q > q
  $ hg revert q
  file not managed: q
  $ rm q

should say file not found

  $ hg revert notfound
  notfound: no such file in rev 334a9e57682c
  $ touch d
  $ hg add d
  $ hg rm a
  $ hg commit -m "second"
  $ echo z > z
  $ hg add z
  $ hg st
  A z
  ? e.orig

should add a, remove d, forget z

  $ hg revert --all -r0
  adding a
  removing d
  forgetting z

should forget a, undelete d

  $ hg revert --all -rtip
  forgetting a
  undeleting d
  $ rm a *.orig

should silently add a

  $ hg revert -r0 a
  $ hg st a
  A a
  $ hg rm d
  $ hg st d
  R d

should silently keep d removed

  $ hg revert -r0 d
  $ hg st d
  R d

  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ chmod +x c
  $ hg revert --all
  reverting c

should print non-executable

  $ test -x c || echo non-executable
  non-executable

  $ chmod +x c
  $ hg commit -m exe

  $ chmod -x c
  $ hg revert --all
  reverting c

should print executable

  $ test -x c && echo executable
  executable

  $ cd ..


Issue241: update and revert produces inconsistent repositories

  $ hg init a
  $ cd a
  $ echo a >> a
  $ hg commit -A -d '1 0' -m a
  adding a
  $ echo a >> a
  $ hg commit -d '2 0' -m a
  $ hg update 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ mkdir b
  $ echo b > b/b

should fail - no arguments

  $ hg revert -rtip
  abort: no files or directories specified
  (use --all to revert all files, or 'hg update 1' to update)
  [255]

should succeed

  $ hg revert --all -rtip
  reverting a


Issue332: confusing message when reverting directory

  $ hg ci -A -m b
  adding b/b
  created new head
  $ echo foobar > b/b
  $ mkdir newdir
  $ echo foo > newdir/newfile
  $ hg add newdir/newfile
  $ hg revert b newdir
  reverting b/b
  forgetting newdir/newfile
  $ echo foobar > b/b
  $ hg revert .
  reverting b/b


reverting a rename target should revert the source

  $ hg mv a newa
  $ hg revert newa
  $ hg st a newa
  ? newa

  $ cd ..

  $ hg init ignored
  $ cd ignored
  $ echo '^ignored$' > .hgignore
  $ echo '^ignoreddir$' >> .hgignore
  $ echo '^removed$' >> .hgignore

  $ mkdir ignoreddir
  $ touch ignoreddir/file
  $ touch ignoreddir/removed
  $ touch ignored
  $ touch removed

4 ignored files (we will add/commit everything)

  $ hg st -A -X .hgignore
  I ignored
  I ignoreddir/file
  I ignoreddir/removed
  I removed
  $ hg ci -qAm 'add files' ignored ignoreddir/file ignoreddir/removed removed

  $ echo >> ignored
  $ echo >> ignoreddir/file
  $ hg rm removed ignoreddir/removed

should revert ignored* and undelete *removed

  $ hg revert -a --no-backup
  reverting ignored
  reverting ignoreddir/file
  undeleting ignoreddir/removed
  undeleting removed
  $ hg st -mardi

  $ hg up -qC
  $ echo >> ignored
  $ hg rm removed

should silently revert the named files

  $ hg revert --no-backup ignored removed
  $ hg st -mardi