view tests/test-stack.t @ 42621:99ebde4fec99

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 test the low-level definition of stack, agnostic from all formatting

Initial setup

  $ cat << EOF >> $HGRCPATH
  > [ui]
  > logtemplate = {rev} {branch} {phase} {desc|firstline}\n
  > [extensions]
  > rebase=
  > [experimental]
  > evolution=createmarkers,exchange,allowunstable
  > EOF

  $ hg init main
  $ cd main
  $ hg branch other
  marked working directory as branch other
  (branches are permanent and global, did you want a bookmark?)
  $ echo aaa > aaa
  $ hg add aaa
  $ hg commit -m c_a
  $ echo aaa > bbb
  $ hg add bbb
  $ hg commit -m c_b
  $ hg branch foo
  marked working directory as branch foo
  $ echo aaa > ccc
  $ hg add ccc
  $ hg commit -m c_c
  $ echo aaa > ddd
  $ hg add ddd
  $ hg commit -m c_d
  $ echo aaa > eee
  $ hg add eee
  $ hg commit -m c_e
  $ echo aaa > fff
  $ hg add fff
  $ hg commit -m c_f
  $ hg log -G
  @  5 foo draft c_f
  |
  o  4 foo draft c_e
  |
  o  3 foo draft c_d
  |
  o  2 foo draft c_c
  |
  o  1 other draft c_b
  |
  o  0 other draft c_a
  

Check that stack doesn't include public changesets
--------------------------------------------------

  $ hg up other
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ hg log -G -r "stack()"
  @  1 other draft c_b
  |
  o  0 other draft c_a
  
  $ hg phase --public 'branch("other")'
  $ hg log -G -r "stack()"
  $ hg up foo
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved

Simple test
-----------

'stack()' list all changeset in the branch

  $ hg branch
  foo
  $ hg log -G -r "stack()"
  @  5 foo draft c_f
  |
  o  4 foo draft c_e
  |
  o  3 foo draft c_d
  |
  o  2 foo draft c_c
  |
  ~

Case with some of the branch unstable
------------------------------------

  $ hg up 3
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo bbb > ddd
  $ hg commit --amend
  2 new orphan changesets
  $ hg log -G
  @  6 foo draft c_d
  |
  | *  5 foo draft c_f
  | |
  | *  4 foo draft c_e
  | |
  | x  3 foo draft c_d
  |/
  o  2 foo draft c_c
  |
  o  1 other public c_b
  |
  o  0 other public c_a
  
  $ hg log -G -r "stack()"
  @  6 foo draft c_d
  |
  ~
  $ hg up -r "desc(c_e)"
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -G -r "stack()"
  @  4 foo draft c_e
  |
  x  3 foo draft c_d
  |
  ~
  $ hg up -r "desc(c_d)"
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg log -G -r "stack()"
  @  6 foo draft c_d
  |
  ~

Case with multiple topological heads
------------------------------------

Make things linear again

  $ hg rebase -s 'desc(c_e)' -d 'desc(c_d) - obsolete()'
  rebasing 4:4f2a69f6d380 "c_e"
  rebasing 5:913c298d8b0a "c_f"
  $ hg log -G
  o  8 foo draft c_f
  |
  o  7 foo draft c_e
  |
  @  6 foo draft c_d
  |
  o  2 foo draft c_c
  |
  o  1 other public c_b
  |
  o  0 other public c_a
  

Create the second branch

  $ hg up 'desc(c_d)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo aaa > ggg
  $ hg add ggg
  $ hg commit -m c_g
  created new head
  $ echo aaa > hhh
  $ hg add hhh
  $ hg commit -m c_h
  $ hg log -G
  @  10 foo draft c_h
  |
  o  9 foo draft c_g
  |
  | o  8 foo draft c_f
  | |
  | o  7 foo draft c_e
  |/
  o  6 foo draft c_d
  |
  o  2 foo draft c_c
  |
  o  1 other public c_b
  |
  o  0 other public c_a
  

Test output

  $ hg log -G -r "stack(10)"
  @  10 foo draft c_h
  |
  o  9 foo draft c_g
  |
  ~
  $ hg log -G -r "stack(8)"
  o  8 foo draft c_f
  |
  o  7 foo draft c_e
  |
  ~
  $ hg log -G -r "stack(head())"
  @  10 foo draft c_h
  |
  o  9 foo draft c_g
  |
  ~
  o  8 foo draft c_f
  |
  o  7 foo draft c_e
  |
  ~
Check the stack order
  $ hg log -r "first(stack())"
  9 foo draft c_g
  $ hg log -r "first(stack(10))"
  9 foo draft c_g
  $ hg log -r "first(stack(8))"
  7 foo draft c_e
  $ hg log -r "first(stack(head()))"
  7 foo draft c_e

Case with multiple heads with unstability involved
--------------------------------------------------

We amend the message to make sure the display base pick the right changeset

  $ hg up 'desc(c_d)'
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo ccc > ddd
  $ hg commit --amend -m 'c_D'
  4 new orphan changesets
  $ hg rebase -d . -s 'desc(c_g)'
  rebasing 9:2ebb6e48ab8a "c_g"
  rebasing 10:634f38e27a1d "c_h"
  $ hg log -G
  o  13 foo draft c_h
  |
  o  12 foo draft c_g
  |
  @  11 foo draft c_D
  |
  | *  8 foo draft c_f
  | |
  | *  7 foo draft c_e
  | |
  | x  6 foo draft c_d
  |/
  o  2 foo draft c_c
  |
  o  1 other public c_b
  |
  o  0 other public c_a
  

We should improve stack definition to also show 12 and 13 here
  $ hg log -G -r "stack()"
  @  11 foo draft c_D
  |
  ~