tests/test-generaldelta.t

revlog: add an aggressivemergedelta option

This adds an option for delta'ing against both p1 and p2 when applying merge
revisions and picking whichever is smallest.

Some before and after stats on manifest.d size:

internal large repo:
before: 1.2 GB
after: 930 MB

mozilla-central:
before: 261 MB
after: 92 MB

Check whether size of generaldelta revlog is not bigger than its
regular equivalent. Test would fail if generaldelta was naive
implementation of parentdelta: third manifest revision would be fully
inserted due to big distance from its paren revision (zero).

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ echo bar > bar
  $ hg commit -q -Am boo
  $ hg clone --pull . ../gdrepo -q --config format.generaldelta=yes
  $ for r in 1 2 3; do
  >   echo $r > foo
  >   hg commit -q -m $r
  >   hg up -q -r 0
  >   hg pull . -q -r $r -R ../gdrepo
  > done

  $ cd ..
  >>> import os
  >>> regsize = os.stat("repo/.hg/store/00manifest.i").st_size
  >>> gdsize = os.stat("gdrepo/.hg/store/00manifest.i").st_size
  >>> if regsize < gdsize:
  ...     print 'generaldata increased size of manifest'

Verify rev reordering doesnt create invalid bundles (issue4462)
This requires a commit tree that when pulled will reorder manifest revs such
that the second manifest to create a file rev will be ordered before the first
manifest to create that file rev. We also need to do a partial pull to ensure
reordering happens. At the end we verify the linkrev points at the earliest
commit.

  $ hg init server --config format.generaldelta=True
  $ cd server
  $ touch a
  $ hg commit -Aqm a
  $ echo x > x
  $ echo y > y
  $ hg commit -Aqm xy
  $ hg up -q '.^'
  $ echo x > x
  $ echo z > z
  $ hg commit -Aqm xz
  $ hg up -q 1
  $ echo b > b
  $ hg commit -Aqm b
  $ hg merge -q 2
  $ hg commit -Aqm merge
  $ echo c > c
  $ hg commit -Aqm c
  $ hg log -G -T '{rev} {shortest(node)} {desc}'
  @  5 ebb8 c
  |
  o    4 baf7 merge
  |\
  | o  3 a129 b
  | |
  o |  2 958c xz
  | |
  | o  1 f00c xy
  |/
  o  0 3903 a
  
  $ cd ..
  $ hg init client
  $ cd client
  $ hg pull -q ../server -r 4
  $ hg debugindex x
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0       3      0       1 1406e7411862 000000000000 000000000000

  $ cd ..

Test format.aggressivemergedeltas

  $ hg init --config format.generaldelta=1 aggressive
  $ cd aggressive
  $ touch a b c d e
  $ hg commit -Aqm side1
  $ hg up -q null
  $ touch x y
  $ hg commit -Aqm side2

- Verify non-aggressive merge uses p1 (commit 1) as delta parent
  $ hg merge -q 0
  $ hg commit -q -m merge
  $ hg debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      59     -1       0 8dde941edb6e 000000000000 000000000000
       1        59      59     -1       1 315c023f341d 000000000000 000000000000
       2       118      65      1       2 2ab389a983eb 315c023f341d 8dde941edb6e

  $ hg strip -q -r . --config extensions.strip=

- Verify aggressive merge uses p2 (commit 0) as delta parent
  $ hg up -q -C 1
  $ hg merge -q 0
  $ hg commit -q -m merge --config format.aggressivemergedeltas=True
  $ hg debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      59     -1       0 8dde941edb6e 000000000000 000000000000
       1        59      59     -1       1 315c023f341d 000000000000 000000000000
       2       118      62      0       2 2ab389a983eb 315c023f341d 8dde941edb6e

  $ cd ..