tests/test-obshistory.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

This test file test the various messages when accessing obsolete
revisions.

Global setup
============

  $ . $TESTDIR/testlib/obsmarker-common.sh
  $ cat >> $HGRCPATH <<EOF
  > [ui]
  > interactive = true
  > [phases]
  > publish=False
  > [experimental]
  > evolution.createmarkers = yes
  > evolution.effect-flags = yes
  > EOF

Test output on amended commit
=============================

Test setup
----------

  $ hg init $TESTTMP/local-amend
  $ cd $TESTTMP/local-amend
  $ mkcommit ROOT
  $ mkcommit A0
  $ echo 42 >> A0
  $ hg commit --amend -m "A1
  > 
  > Better commit message"
  $ hg log --hidden -G
  @  changeset:   2:4ae3a4151de9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:4ae3a4151de9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden "desc(A0)"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9)

Test output with pruned commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-prune
  $ cd $TESTTMP/local-prune
  $ mkcommit ROOT
  $ mkcommit A0 # 0
  $ mkcommit B0 # 1
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg debugobsolete --record-parents `getid 'desc(B0)'`
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  obsolete:    pruned
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

Actual test
-----------
  $ hg up 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg up 0dec01379d3b
  abort: hidden revision '0dec01379d3b' is pruned!
  (use --hidden to access hidden revisions)
  [255]
  $ hg up --hidden -r 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' is pruned)

Test output with splitted commit
================================

Test setup
----------

  $ hg init $TESTTMP/local-split
  $ cd $TESTTMP/local-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding a
  adding b
  $ hg log --hidden -G
  @  changeset:   1:471597cad322
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'`
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:f257fde29c7a
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:471597cad322
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471597cad322
  abort: hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471597cad322
  (hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a)

Test output with lots of splitted commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-lots-split
  $ cd $TESTTMP/local-lots-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ echo 44 >> c
  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding a
  adding b
  adding c
  adding d
  $ hg log --hidden -G
  @  changeset:   1:de7290d8b885
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ echo 44 >> c
  $ hg commit -A -m "A0"
  adding c

  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding d

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'` `getid '4'` `getid '5'`
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   5:c7f044602e9b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   4:1ae8bc733a14
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   3:f257fde29c7a
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:de7290d8b885
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a, 4:1ae8bc733a14, 5:c7f044602e9b
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update de7290d8b885
  abort: hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset de7290d8b885
  (hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more)

Test output with folded commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-fold
  $ cd $TESTTMP/local-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B0)'` `getid 'desc(C0)'`
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   2:0dec01379d3b
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 3:eb5a0daa2192
  | |  summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 3:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  abort: hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)

Test output with divergence
===========================

Test setup
----------

  $ hg init $TESTTMP/local-divergence
  $ cd $TESTTMP/local-divergence
  $ mkcommit ROOT
  $ mkcommit A0
  $ hg commit --amend -m "A1"
  $ hg log --hidden -G
  @  changeset:   2:fdf9bde5129a
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: fdf9bde5129a)
  $ hg commit --amend -m "A2"
  2 new content-divergent changesets
  $ hg log --hidden -G
  @  changeset:   3:65b757b745b9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  instability: content-divergent
  |  summary:     A2
  |
  | *  changeset:   2:fdf9bde5129a
  |/   parent:      0:ea207398892e
  |    user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    instability: content-divergent
  |    summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    obsolete:    rewritten using amend as 3:65b757b745b9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' has diverged!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' has diverged)

Test output with amended + folded commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-amend-fold
  $ cd $TESTTMP/local-amend-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg commit --amend -m "B1"
  $ hg log --hidden -G
  @  changeset:   3:b7ea6d14e664
  |  tag:         tip
  |  parent:      1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B1
  |
  | x  changeset:   2:0dec01379d3b
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  |    summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B1)'` `getid 'desc(C0)'`
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   4:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   3:b7ea6d14e664
  | |  parent:      1:471f378eab4c
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 4:eb5a0daa2192
  | |  summary:     B1
  | |
  | | x  changeset:   2:0dec01379d3b
  | |/   user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  | |    summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 4:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192!
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update --hidden 0dec01379d3b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg update --hidden 'desc(B0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved