tests/test-sparse-verbose-json.t

revlog: add a C implementation of `headrevsdiff`

Python implementation of `headrevsdiff` can be very slow in the worst
case compared with the `heads` computation it replaces, since the
latter is done in C.

Even the average case of this Python implementation is still
noticeable in the profiles.

This patch makes the computation much much faster by doing it in C.

test sparse with --verbose and -T json

  $ hg init myrepo
  $ cd myrepo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=
  > strip=
  > EOF

  $ echo a > show
  $ echo x > hide
  $ hg ci -Aqm 'initial'

  $ echo b > show
  $ echo y > hide
  $ echo aa > show2
  $ echo xx > hide2
  $ hg ci -Aqm 'two'

Verify basic --include and --reset

  $ hg up -q 0
  $ hg debugsparse --include 'hide' -Tjson
  [
   {
    "exclude_rules_added": 0,
    "files_added": 0,
    "files_conflicting": 0,
    "files_dropped": 1,
    "include_rules_added": 1,
    "profiles_added": 0
   }
  ]
  $ hg debugsparse --clear-rules
  $ hg debugsparse --include 'hide' --verbose
  removing show
  Profiles changed: 0
  Include rules changed: 1
  Exclude rules changed: 0

  $ hg debugsparse --reset -Tjson
  [
   {
    "exclude_rules_added": 0,
    "files_added": 1,
    "files_conflicting": 0,
    "files_dropped": 0,
    "include_rules_added": -1,
    "profiles_added": 0
   }
  ]
  $ hg debugsparse --include 'hide'
  $ hg debugsparse --reset --verbose
  getting show
  Profiles changed: 0
  Include rules changed: -1
  Exclude rules changed: 0

Verifying that problematic files still allow us to see the deltas when forcing:

  $ hg debugsparse --include 'show*'
  $ touch hide
  $ hg debugsparse --delete 'show*' --force -Tjson
  pending changes to 'hide'
  [
   {
    "exclude_rules_added": 0,
    "files_added": 0,
    "files_conflicting": 1,
    "files_dropped": 0,
    "include_rules_added": -1,
    "profiles_added": 0
   }
  ]
  $ hg debugsparse --include 'show*' --force
  pending changes to 'hide'
  $ hg debugsparse --delete 'show*' --force --verbose
  pending changes to 'hide'
  Profiles changed: 0
  Include rules changed: -1
  Exclude rules changed: 0