tests/test-merge-remove.t

revlog: move file writing to a separate function

Moves the code that actually writes to a file to a separate function in
revlog.py. This allows extensions to intercept and use the data being written to
disk. For example, an extension might want to replicate these writes elsewhere.

When cloning the Mercurial repo on /dev/shm with --pull, I see about a 0.3% perf change.
It goes from 28.2 to 28.3 seconds.

  $ hg init

  $ echo foo > foo
  $ echo bar > bar
  $ hg ci -qAm 'add foo bar'

  $ echo foo2 >> foo
  $ echo bleh > bar
  $ hg ci -m 'change foo bar'

  $ hg up -qC 0
  $ hg mv foo foo1
  $ echo foo1 > foo1
  $ hg cat foo >> foo1
  $ hg ci -m 'mv foo foo1'
  created new head

  $ hg merge
  merging foo1 and foo to foo1
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg debugstate --nodates
  n   0         -2 bar
  m 644         14 foo1
  copy: foo -> foo1

  $ hg st -q
  M bar
  M foo1


Removing foo1 and bar:

  $ cp foo1 F
  $ cp bar B
  $ hg rm -f foo1 bar

  $ hg debugstate --nodates
  r   0         -2 bar
  r   0         -1 foo1
  copy: foo -> foo1

  $ hg st -qC
  R bar
  R foo1


Re-adding foo1 and bar:

  $ cp F foo1
  $ cp B bar
  $ hg add -v foo1 bar
  adding bar
  adding foo1

  $ hg debugstate --nodates
  n   0         -2 bar
  m 644         14 foo1
  copy: foo -> foo1

  $ hg st -qC
  M bar
  M foo1
    foo


Reverting foo1 and bar:

  $ hg revert -vr . foo1 bar
  saving current version of bar as bar.orig
  reverting bar
  saving current version of foo1 as foo1.orig
  reverting foo1

  $ hg debugstate --nodates
  n   0         -2 bar
  m 644         14 foo1
  copy: foo -> foo1

  $ hg st -qC
  M bar
  M foo1
    foo

  $ hg diff