tests/test-convert-bzr-merges.t

commit: improve the files field of changelog for merges

Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.

This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
  -v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
  manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
  filelogs for pointless files (the constant factors for opening even
  a tiny filelog is apparently pretty bad)

So stop listing such files as described in the code.  Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).

The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
  description that contain diffs,
- merge commits from the convert extension don't have the right files
  list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
  commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
  would really build the right thing

I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).

Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge, 733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).

Differential Revision: https://phab.mercurial-scm.org/D6613

#require bzr

N.B. bzr 1.13 has a bug that breaks this test.  If you see this
test fail, check your bzr version.  Upgrading to bzr 1.13.1
should fix it.

  $ . "$TESTDIR/bzr-definitions"

test multiple merges at once

  $ mkdir test-multimerge
  $ cd test-multimerge
  $ bzr init -q source
  $ cd source
  $ echo content > file
  $ echo text > rename_me
  $ bzr add -q file rename_me
  $ bzr commit -q -m 'Initial add' '--commit-time=2009-10-10 08:00:00 +0100'
  $ cd ..
  $ bzr branch -q source source-branch1
  $ cd source-branch1
  $ echo morecontent >> file
  $ echo evenmorecontent > file-branch1
  $ bzr add -q file-branch1
  $ bzr commit -q -m 'Added branch1 file' '--commit-time=2009-10-10 08:00:01 +0100'
  $ cd ../source
  $ sleep 1
  $ echo content > file-parent
  $ bzr add -q file-parent
  $ bzr commit -q -m 'Added parent file' '--commit-time=2009-10-10 08:00:02 +0100'
  $ cd ..
  $ bzr branch -q source source-branch2
  $ cd source-branch2
  $ echo somecontent > file-branch2
  $ bzr add -q file-branch2
  $ bzr mv -q rename_me renamed
  $ echo change > renamed
  $ bzr commit -q -m 'Added brach2 file' '--commit-time=2009-10-10 08:00:03 +0100'
  $ sleep 1
  $ cd ../source
  $ bzr merge -q ../source-branch1
  $ bzr merge -q --force ../source-branch2
  $ bzr commit -q -m 'Merged branches' '--commit-time=2009-10-10 08:00:04 +0100'
  $ cd ..

BUG: file-branch2 should not be added in rev 4, and the rename_me -> renamed
move should be recorded in the fixup merge.
  $ hg convert --datesort --config convert.bzr.saverev=False source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  4 Initial add
  3 Added branch1 file
  2 Added parent file
  1 Added brach2 file
  0 Merged branches
  warning: can't find ancestor for 'renamed' copied from 'rename_me'!
  $ glog -R source-hg
  o    5@source "(octopus merge fixup)" files+: [], files-: [], files: [renamed]
  |\
  | o    4@source "Merged branches" files+: [file-branch2 renamed], files-: [rename_me], files: []
  | |\
  o---+  3@source-branch2 "Added brach2 file" files+: [file-branch2 renamed], files-: [rename_me], files: []
   / /
  | o  2@source "Added parent file" files+: [file-parent], files-: [], files: []
  | |
  o |  1@source-branch1 "Added branch1 file" files+: [file-branch1], files-: [], files: [file]
  |/
  o  0@source "Initial add" files+: [file rename_me], files-: [], files: []
  
  $ manifest source-hg tip
  % manifest of tip
  644   file
  644   file-branch1
  644   file-branch2
  644   file-parent
  644   renamed

  $ hg convert source-hg hg2hg
  initializing destination hg2hg repository
  scanning source...
  sorting...
  converting...
  5 Initial add
  4 Added branch1 file
  3 Added parent file
  2 Added brach2 file
  1 Merged branches
  0 (octopus merge fixup)

BUG: The manifest entries should be the same for matching revisions, and
nothing should be outgoing

  $ hg -R source-hg manifest --debug -r tip | grep renamed
  67109fdebf6c556eb0a9d5696dd98c8420520405 644   renamed
  $ hg -R hg2hg manifest --debug -r tip | grep renamed
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed
  $ hg -R source-hg manifest --debug -r 'tip^' | grep renamed
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed
  $ hg -R hg2hg manifest --debug -r 'tip^' | grep renamed
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed

BUG: The revisions found should be the same in both repos

  $ hg --cwd source-hg log -r 'file("renamed")' -G -Tcompact
  o    5[tip]:4,3   6652429c300a   2009-10-10 08:00 +0100   foo
  |\     (octopus merge fixup)
  | |
  | o    4:2,1   e0ae8af3503a   2009-10-10 08:00 +0100   foo
  | |\     Merged branches
  | ~ ~
  o  3   138bed2e14be   2009-10-10 08:00 +0100   foo
  |    Added brach2 file
  ~
  $ hg --cwd hg2hg log -r 'file("renamed")' -G -Tcompact
  o    4:2,1   e0ae8af3503a   2009-10-10 08:00 +0100   foo
  |\     Merged branches
  ~ ~
  o  3   138bed2e14be   2009-10-10 08:00 +0100   foo
  |    Added brach2 file
  ~

BUG(?): The move seems to be recorded in rev 4, so it should probably show up
there.  It's not recorded as a move in rev 5, even in source-hg.

  $ hg -R source-hg up -q tip
  $ hg -R hg2hg up -q tip
  $ hg --cwd source-hg log -r 'follow("renamed")' -G -Tcompact
  @    5[tip]:4,3   6652429c300a   2009-10-10 08:00 +0100   foo
  |\     (octopus merge fixup)
  | :
  o :  3   138bed2e14be   2009-10-10 08:00 +0100   foo
  :/     Added brach2 file
  :
  o  0   18b86f5df51b   2009-10-10 08:00 +0100   foo
       Initial add
  
  $ hg --cwd hg2hg log -r 'follow("renamed")' -G -Tcompact
  o  3   138bed2e14be   2009-10-10 08:00 +0100   foo
  :    Added brach2 file
  :
  o  0   18b86f5df51b   2009-10-10 08:00 +0100   foo
       Initial add
  

  $ hg -R hg2hg out source-hg -T compact
  comparing with source-hg
  searching for changes
  5[tip]:4,3   3be2299ccd31   2009-10-10 08:00 +0100   foo
    (octopus merge fixup)
  

  $ glog -R hg2hg
  @    5@source "(octopus merge fixup)" files+: [], files-: [], files: []
  |\
  | o    4@source "Merged branches" files+: [file-branch2 renamed], files-: [rename_me], files: []
  | |\
  o---+  3@source-branch2 "Added brach2 file" files+: [file-branch2 renamed], files-: [rename_me], files: []
   / /
  | o  2@source "Added parent file" files+: [file-parent], files-: [], files: []
  | |
  o |  1@source-branch1 "Added branch1 file" files+: [file-branch1], files-: [], files: [file]
  |/
  o  0@source "Initial add" files+: [file rename_me], files-: [], files: []
  

  $ hg -R source-hg log --debug -r tip
  changeset:   5:6652429c300ab66fdeaf2e730945676a00b53231
  branch:      source
  tag:         tip
  phase:       draft
  parent:      4:e0ae8af3503af9bbffb0b29268a02744cc61a561
  parent:      3:138bed2e14be415a2692b02e41405b2864f758b4
  manifest:    5:1eabd5f5d4b985784cf2c45c717ff053eca14b0d
  user:        Foo Bar <[e-mail]>
  date:        Sat Oct 10 08:00:04 2009 +0100
  files:       renamed
  extra:       branch=source
  description:
  (octopus merge fixup)
  
  
  $ hg -R hg2hg log --debug -r tip
  changeset:   5:3be2299ccd315ff9aab2b49bdb0d14e3244435e8
  branch:      source
  tag:         tip
  phase:       draft
  parent:      4:e0ae8af3503af9bbffb0b29268a02744cc61a561
  parent:      3:138bed2e14be415a2692b02e41405b2864f758b4
  manifest:    4:3ece3c7f2cc6df15b3cbbf3273c69869fc7c3ab0
  user:        Foo Bar <[e-mail]>
  date:        Sat Oct 10 08:00:04 2009 +0100
  extra:       branch=source
  description:
  (octopus merge fixup)
  
  
  $ hg -R source-hg manifest --debug -r tip
  cdf31ed9242b209cd94697112160e2c5b37a667d 644   file
  5108144f585149b29779d7c7e51d61dd22303ffe 644   file-branch1
  80753c4a9ac3806858405b96b24a907b309e3616 644   file-branch2
  7108421418404a937c684d2479a34a24d2ce4757 644   file-parent
  67109fdebf6c556eb0a9d5696dd98c8420520405 644   renamed
  $ hg -R source-hg manifest --debug -r 'tip^'
  cdf31ed9242b209cd94697112160e2c5b37a667d 644   file
  5108144f585149b29779d7c7e51d61dd22303ffe 644   file-branch1
  80753c4a9ac3806858405b96b24a907b309e3616 644   file-branch2
  7108421418404a937c684d2479a34a24d2ce4757 644   file-parent
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed

  $ hg -R hg2hg manifest --debug -r tip
  cdf31ed9242b209cd94697112160e2c5b37a667d 644   file
  5108144f585149b29779d7c7e51d61dd22303ffe 644   file-branch1
  80753c4a9ac3806858405b96b24a907b309e3616 644   file-branch2
  7108421418404a937c684d2479a34a24d2ce4757 644   file-parent
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed
  $ hg -R hg2hg manifest --debug -r 'tip^'
  cdf31ed9242b209cd94697112160e2c5b37a667d 644   file
  5108144f585149b29779d7c7e51d61dd22303ffe 644   file-branch1
  80753c4a9ac3806858405b96b24a907b309e3616 644   file-branch2
  7108421418404a937c684d2479a34a24d2ce4757 644   file-parent
  27c968376d7c3afd095ecb9c7697919b933448c8 644   renamed

  $ cd ..