tests/test-diffstat.t

parsers: optimize filtered headrevs logic

The old native head revs logic would iterate over every node, starting from 0,
and check if every node was filtered (by testing it against the filteredrevs
python set). On large repos with hundreds of thousands of commits, this could
take 150ms.

This new logic iterates over the nodes in reverse order, and skips the filtered
check if we've seen an unfiltered child of the node. This saves approximately a
bagillion filteredrevs set checks, which shaves the time down from 150ms to
20ms during every branch cache write.

  $ hg init repo
  $ cd repo
  $ i=0; while [ "$i" -lt 213 ]; do echo a >> a; i=`expr $i + 1`; done
  $ hg add a
  $ cp a b
  $ hg add b

Wide diffstat:

  $ hg diff --stat
   a |  213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   b |  213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   2 files changed, 426 insertions(+), 0 deletions(-)

diffstat width:

  $ COLUMNS=24 hg diff --config ui.interactive=true --stat
   a |  213 ++++++++++++++
   b |  213 ++++++++++++++
   2 files changed, 426 insertions(+), 0 deletions(-)

  $ hg ci -m adda

  $ cat >> a <<EOF
  > a
  > a
  > a
  > EOF

Narrow diffstat:

  $ hg diff --stat
   a |  3 +++
   1 files changed, 3 insertions(+), 0 deletions(-)

  $ hg ci -m appenda

  >>> open("c", "wb").write("\0")
  $ touch d
  $ hg add c d

Binary diffstat:

  $ hg diff --stat
   c |  Bin 
   1 files changed, 0 insertions(+), 0 deletions(-)

Binary git diffstat:

  $ hg diff --stat --git
   c |  Bin 
   d |    0 
   2 files changed, 0 insertions(+), 0 deletions(-)

  $ hg ci -m createb

  >>> open("file with spaces", "wb").write("\0")
  $ hg add "file with spaces"

Filename with spaces diffstat:

  $ hg diff --stat
   file with spaces |  Bin 
   1 files changed, 0 insertions(+), 0 deletions(-)

Filename with spaces git diffstat:

  $ hg diff --stat --git
   file with spaces |  Bin 
   1 files changed, 0 insertions(+), 0 deletions(-)

diffstat within directories:

  $ hg rm -f 'file with spaces'

  $ mkdir dir1 dir2
  $ echo new1 > dir1/new
  $ echo new2 > dir2/new
  $ hg add dir1/new dir2/new
  $ hg diff --stat
   dir1/new |  1 +
   dir2/new |  1 +
   2 files changed, 2 insertions(+), 0 deletions(-)

  $ hg diff --stat --root dir1
   new |  1 +
   1 files changed, 1 insertions(+), 0 deletions(-)

  $ hg diff --stat --root dir1 dir2
  warning: dir2 not inside relative root dir1

  $ hg diff --stat --root dir1 -I dir1/old

  $ cd dir1
  $ hg diff --stat .
   dir1/new |  1 +
   1 files changed, 1 insertions(+), 0 deletions(-)
  $ hg diff --stat --root .
   new |  1 +
   1 files changed, 1 insertions(+), 0 deletions(-)

  $ hg diff --stat --root ../dir1 ../dir2
  warning: ../dir2 not inside relative root . (glob)

  $ hg diff --stat --root . -I old

  $ cd ..