tests/test-narrow-debugrebuilddirstate.t

annotate: do not construct attr.s object per line while computing history

Unfortunately, good abstraction has a cost. It's way slower to construct
an annotateline() object than creating a plain tuple or a list. This patch
changes the internal data structure from row-based to columnar, so the
decorate() function can be instant (i.e. no Python in hot loop.)

For code readability, the outermost tuple is switched to an attr.s object
instead.

  (original, row-based attr.s)
  $ hg annot mercurial/commands.py --time > /dev/null
  time: real 11.470 secs (user 11.400+0.000 sys 0.070+0.000)
  $ hg annot mercurial/commands.py --time --line-number > /dev/null
  time: real 39.590 secs (user 39.500+0.000 sys 0.080+0.000)

  (this patch, columnar)
  $ hg annot mercurial/commands.py --time > /dev/null
  time: real 11.780 secs (user 11.710+0.000 sys 0.070+0.000)
  $ hg annot mercurial/commands.py --time --line-number > /dev/null
  time: real 12.240 secs (user 12.170+0.000 sys 0.090+0.000)

  (cf. 4.3.3, row-based tuple)
  $ hg annot mercurial/commands.py --time --line-number > /dev/null
  time: real 19.540 secs (user 19.460+0.000 sys 0.080+0.000)

  $ . "$TESTDIR/narrow-library.sh"
  $ hg init master
  $ cd master
  $ echo treemanifest >> .hg/requires
  $ echo 'contents of file' > file
  $ mkdir foo
  $ echo 'contents of foo/bar' > foo/bar
  $ hg ci -Am 'some change'
  adding file
  adding foo/bar

  $ cd ..
  $ hg clone --narrow ssh://user@dummy/master copy --include=foo
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets * (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd copy

  $ hg debugdirstate
  n *         20 unset               foo/bar (glob)
  $ mv .hg/dirstate .hg/old_dirstate
  $ dd bs=40 count=1 if=.hg/old_dirstate of=.hg/dirstate 2>/dev/null
  $ hg debugdirstate
  $ hg debugrebuilddirstate
  $ hg debugdirstate
  n *         * unset               foo/bar (glob)