tests/test-rebuildstate.t

bundle2: implement consume() API on unbundlepart

We want bundle parts to not be seekable by default. That means
eliminating the generic seek() method.

A common pattern in bundle2.py is to seek to the end of the part
data. This is mainly used by the part iteration code to ensure
the underlying stream is advanced to the next bundle part.

In this commit, we establish a dedicated API for consuming a
bundle2 part data. We switch users of seek() to it.

The old implementation of seek(0, os.SEEK_END) would effectively
call self.read(). The new implementation calls self.read(32768)
in a loop. The old implementation would therefore assemble a
buffer to hold all remaining data being seeked over. For seeking
over large bundle parts, this would involve a large allocation and
a lot of overhead to collect intermediate data! This overhead can
be seen in the results for `hg perfbundleread`:

! bundle2 iterparts()
! wall 10.891305 comb 10.820000 user 7.990000 sys 2.830000 (best of 3)
! wall 8.070791 comb 8.060000 user 7.180000 sys 0.880000 (best of 3)
! bundle2 part seek()
! wall 12.991478 comb 10.390000 user 7.720000 sys 2.670000 (best of 3)
! wall 10.370142 comb 10.350000 user 7.430000 sys 2.920000 (best of 3)

Of course, skipping over large payload data isn't likely very common.
So I doubt the performance wins will be observed in the wild.

Differential Revision: https://phab.mercurial-scm.org/D1388

  $ cat > adddrop.py <<EOF
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'debugadddrop',
  >   [('', 'drop', False, 'drop file from dirstate', 'FILE'),
  >    ('', 'normal-lookup', False, 'add file to dirstate', 'FILE')],
  >     'hg debugadddrop')
  > def debugadddrop(ui, repo, *pats, **opts):
  >   '''Add or drop unnamed arguments to or from the dirstate'''
  >   drop = opts.get('drop')
  >   nl = opts.get('normal_lookup')
  >   if nl and drop:
  >       raise error.Abort('drop and normal-lookup are mutually exclusive')
  >   wlock = repo.wlock()
  >   try:
  >     for file in pats:
  >       if opts.get('normal_lookup'):
  >         repo.dirstate.normallookup(file)
  >       else:
  >         repo.dirstate.drop(file)
  > 
  >     repo.dirstate.write(repo.currenttransaction())
  >   finally:
  >     wlock.release()
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "debugadddrop=`pwd`/adddrop.py" >> $HGRCPATH

basic test for hg debugrebuildstate

  $ hg init repo
  $ cd repo

  $ touch foo bar
  $ hg ci -Am 'add foo bar'
  adding bar
  adding foo

  $ touch baz
  $ hg add baz
  $ hg rm bar

  $ hg debugrebuildstate

state dump after

  $ hg debugstate --nodates | sort
  n   0         -1 unset               bar
  n   0         -1 unset               foo

  $ hg debugadddrop --normal-lookup file1 file2
  $ hg debugadddrop --drop bar
  $ hg debugadddrop --drop
  $ hg debugstate --nodates
  n   0         -1 unset               file1
  n   0         -1 unset               file2
  n   0         -1 unset               foo
  $ hg debugrebuildstate

status

  $ hg st -A
  ! bar
  ? baz
  C foo

Test debugdirstate --minimal where a file is not in parent manifest
but in the dirstate
  $ touch foo bar qux
  $ hg add qux
  $ hg remove bar
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo
  $ hg debugadddrop --normal-lookup baz
  $ hg debugdirstate --nodates
  r   0          0 * bar (glob)
  n   0         -1 * baz (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --nodates
  r   0          0 * bar (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo

Test debugdirstate --minimal where file is in the parent manifest but not the
dirstate
  $ hg manifest
  bar
  foo
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo
  $ hg debugdirstate --nodates
  r   0          0 * bar (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg debugadddrop --drop foo
  $ hg debugdirstate --nodates
  r   0          0 * bar (glob)
  a   0         -1 * qux (glob)
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --nodates
  r   0          0 * bar (glob)
  n   0         -1 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo