tests/test-http-branchmap.t

log: speed up single file log with hidden revs (issue4747)

On repos with lots of heads, the filelog() code could spend several
minutes decompressing manifests. This change instead tries to
efficiently scan the changelog for candidates and decompress as few
manifests as possible. This is a regression introduced in 3.3 by the
linkrev adjustment code. Prior to that, filelog was nearly instant.

For the repo in the bug report, this improves time of a simple log
command from ~3 minutes to ~.5 seconds, a 360x speedup.

For the main Mercurial repo, a log of commands.py slows down from
1.14s to 1.45s, a 27% slowdown. This is still faster than the file()
revset, which takes 2.1 seconds.

#require killdaemons

  $ hgserve() {
  >     hg serve -a localhost -p $HGPORT1 -d --pid-file=hg.pid \
  >       -E errors.log -v $@ > startup.log
  >     # Grepping hg serve stdout would hang on Windows
  >     grep -v 'listening at' startup.log
  >     cat hg.pid >> "$DAEMON_PIDS"
  > }
  $ hg init a
  $ hg --encoding utf-8 -R a branch æ
  marked working directory as branch \xc3\xa6 (esc)
  (branches are permanent and global, did you want a bookmark?)
  $ echo foo > a/foo
  $ hg -R a ci -Am foo
  adding foo
  $ hgserve -R a --config web.push_ssl=False --config web.allow_push=* --encoding latin1
  $ hg --encoding utf-8 clone http://localhost:$HGPORT1 b
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch \xc3\xa6 (esc)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding utf-8 -R b log
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ echo bar >> b/foo
  $ hg -R b ci -m bar
  $ hg --encoding utf-8 -R b push
  pushing to http://localhost:$HGPORT1/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ hg -R a --encoding utf-8 log
  changeset:   1:58e7c90d67cb
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     bar
  
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ killdaemons.py hg.pid

verify 7e7d56fe4833 (encoding fallback in branchmap to maintain compatibility with 1.3.x)

  $ cat <<EOF > oldhg
  > import sys
  > from mercurial import ui, hg, commands
  > 
  > class StdoutWrapper(object):
  >     def __init__(self, stdout):
  >         self._file = stdout
  > 
  >     def write(self, data):
  >         if data == '47\n':
  >             # latin1 encoding is one %xx (3 bytes) shorter
  >             data = '44\n'
  >         elif data.startswith('%C3%A6 '):
  >             # translate to latin1 encoding
  >             data = '%%E6 %s' % data[7:]
  >         self._file.write(data)
  > 
  >     def __getattr__(self, name):
  >         return getattr(self._file, name)
  > 
  > sys.stdout = StdoutWrapper(sys.stdout)
  > sys.stderr = StdoutWrapper(sys.stderr)
  > 
  > myui = ui.ui()
  > repo = hg.repository(myui, 'a')
  > commands.serve(myui, repo, stdio=True, cmdserver=False)
  > EOF
  $ echo baz >> b/foo
  $ hg -R b ci -m baz
  $ hg push -R b -e 'python oldhg' ssh://dummy/ --encoding latin1
  pushing to ssh://dummy/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files