view tests/test-generaldelta.t @ 29859:a1092e2d70a3

help: internals topic for wire protocol

The Mercurial wire protocol is under-documented. This includes a lack
of source docstrings and comments as well as pages on the official
wiki.

This patch adds the beginnings of "internals" documentation on the
wire protocol.

The documentation should have nearly complete coverage on the
lower-level parts of the protocol, such as the different transport
mechanims, how commands and arguments are sent, capabilities, and,
of course, the commands themselves.

As part of writing this documentation, I discovered a number of
deficiencies in the protocol and bugs in the implementation. I've
started sending patches for some of the issues. I hope to send a lot
more.

This patch starts with the scaffolding for a new internals page.

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 --config format.generaldelta=no --config format.usegeneraldelta=no
  $ cd repo
  $ echo foo > foo
  $ echo bar > bar
  $ echo baz > baz
  $ 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 ..
  >>> from __future__ import print_function
  >>> 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 --config format.generaldelta=false --config format.usegeneraldelta=false
  $ 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 "usegeneraldelta" config
(repo are general delta, but incoming bundle are not re-deltified)

delta coming from the server base delta server are not recompressed.
(also include the aggressive version for comparison)

  $ hg clone repo --pull --config format.usegeneraldelta=1 usegd
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 6 changes to 3 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg clone repo --pull --config format.generaldelta=1 full
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 6 changes to 3 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -R repo debugindex -m
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0     104      0       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      0       2 134fdc6fd680 cef96823c800 000000000000
       3       218     104      3       3 723508934dad cef96823c800 000000000000
  $ hg -R usegd debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0     104     -1       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      1       2 134fdc6fd680 cef96823c800 000000000000
       3       218      57      0       3 723508934dad cef96823c800 000000000000
  $ hg -R full debugindex -m
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0     104     -1       0 cef96823c800 000000000000 000000000000
       1       104      57      0       1 58ab9a8d541d cef96823c800 000000000000
       2       161      57      0       2 134fdc6fd680 cef96823c800 000000000000
       3       218      57      0       3 723508934dad cef96823c800 000000000000

Test format.aggressivemergedeltas

  $ hg init --config format.generaldelta=1 aggressive
  $ cd aggressive
  $ cat << EOF >> .hg/hgrc
  > [format]
  > generaldelta = 1
  > EOF
  $ 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      61      0       1 315c023f341d 000000000000 000000000000
       2       120      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      61      0       1 315c023f341d 000000000000 000000000000
       2       120      62      0       2 2ab389a983eb 315c023f341d 8dde941edb6e

Test that strip bundle use bundle2
  $ hg --config extensions.strip= strip .
  0 files updated, 0 files merged, 5 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/aggressive/.hg/strip-backup/1c5d4dc9a8b8-6c68e60c-backup.hg (glob)
  $ hg debugbundle .hg/strip-backup/*
  Stream params: sortdict([('Compression', 'BZ')])
  changegroup -- "sortdict([('version', '02'), ('nbchanges', '1')])"
      1c5d4dc9a8b8d6e1750966d343e94db665e7a1e9

  $ cd ..