tests/test-rebase-pull.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

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > histedit=
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}' {branches}\n"
  > EOF


  $ hg init a
  $ cd a

  $ echo C1 > C1
  $ hg ci -Am C1
  adding C1

  $ echo C2 > C2
  $ hg ci -Am C2
  adding C2

  $ cd ..

  $ hg clone a b
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone a c
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd b

  $ echo L1 > L1
  $ hg ci -Am L1
  adding L1


  $ cd ../a

  $ echo R1 > R1
  $ hg ci -Am R1
  adding R1


  $ cd ../b

Now b has one revision to be pulled from a:

  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 77ae9631bcca
  rebasing 2:ff8d69a621f9 "L1"
  saved backup bundle to $TESTTMP/b/.hg/strip-backup/ff8d69a621f9-160fa373-rebase.hg

  $ hg tglog
  @  3: d80cc2da061e 'L1'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
Re-run:

  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  no changes found

Abort pull early if working dir is not clean:

  $ echo L1-mod > L1
  $ hg pull --rebase
  abort: uncommitted changes
  (cannot pull with rebase: please commit or shelve your changes first)
  [255]
  $ hg update --clean --quiet

Abort pull early if another operation (histedit) is in progress:

  $ hg histedit . -q --commands - << EOF
  > edit d80cc2da061e histedit: generate unfinished state
  > EOF
  Editing (d80cc2da061e), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ hg pull --rebase
  abort: histedit in progress
  (use 'hg histedit --continue' or 'hg histedit --abort')
  [255]
  $ hg histedit --abort --quiet

Abort pull early with pending uncommitted merge:

  $ cd ..
  $ hg clone --noupdate c d
  $ cd d
  $ hg tglog
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
  $ hg update --quiet 0
  $ echo M1 > M1
  $ hg commit --quiet -Am M1
  $ hg update --quiet 1
  $ hg merge 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg pull --rebase
  abort: outstanding uncommitted merge
  (cannot pull with rebase: please commit or shelve your changes first)
  [255]
  $ hg update --clean --quiet

Abort pull early with unclean subrepo:
  $ echo s = s > .hgsub
  $ hg add .hgsub
  $ hg init s
  $ hg commit -m "generated a subrepo"
  $ echo a > s/a
  $ hg -R s add s/a
  $ hg pull --rebase
  abort: uncommitted changes in subrepository "s"
  (cannot pull with rebase: please commit or shelve your changes first)
  [255]

Invoke pull --rebase and nothing to rebase:

  $ cd ../c

  $ hg book norebase
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 77ae9631bcca
  nothing to rebase - updating instead
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updating bookmark norebase

  $ hg tglog -l 1
  @  2: 77ae9631bcca 'R1'
  |
  ~

pull --rebase --update should ignore --update:

  $ hg pull --rebase --update
  pulling from $TESTTMP/a
  searching for changes
  no changes found

pull --rebase doesn't update if nothing has been pulled:

  $ hg up -q 1

  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  no changes found

  $ hg tglog -l 1
  o  2: 77ae9631bcca 'R1'
  |
  ~

  $ cd ..

pull --rebase works when a specific revision is pulled (issue3619)

  $ cd a
  $ hg tglog
  @  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
  $ echo R2 > R2
  $ hg ci -Am R2
  adding R2
  $ echo R3 > R3
  $ hg ci -Am R3
  adding R3
  $ cd ../c
  $ hg tglog
  o  2: 77ae9631bcca 'R1'
  |
  @  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
  $ echo L1 > L1
  $ hg ci -Am L1
  adding L1
  created new head
  $ hg pull --rev tip --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  new changesets 31cd3a05214e:770a61882ace
  rebasing 3:ff8d69a621f9 "L1"
  saved backup bundle to $TESTTMP/c/.hg/strip-backup/ff8d69a621f9-160fa373-rebase.hg
  $ hg tglog
  @  5: 518d153c0ba3 'L1'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
pull --rebase works with bundle2 turned on

  $ cd ../a
  $ echo R4 > R4
  $ hg ci -Am R4
  adding R4
  $ hg tglog
  @  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
  $ cd ../c
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 00e3b7781125
  rebasing 5:518d153c0ba3 "L1"
  saved backup bundle to $TESTTMP/c/.hg/strip-backup/518d153c0ba3-73407f14-rebase.hg
  $ hg tglog
  @  6: 0d0727eb7ce0 'L1'
  |
  o  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  

pull --rebase only update if there is nothing to rebase

  $ cd ../a
  $ echo R5 > R5
  $ hg ci -Am R5
  adding R5
  $ hg tglog
  @  6: 88dd24261747 'R5'
  |
  o  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  
  $ cd ../c
  $ echo L2 > L2
  $ hg ci -Am L2
  adding L2
  $ hg up 'desc(L1)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 88dd24261747
  rebasing 6:0d0727eb7ce0 "L1"
  rebasing 7:c1f58876e3bf "L2"
  saved backup bundle to $TESTTMP/c/.hg/strip-backup/0d0727eb7ce0-ef61ccb2-rebase.hg
  $ hg tglog
  o  8: 6dc0ea5dcf55 'L2'
  |
  @  7: 864e0a2d2614 'L1'
  |
  o  6: 88dd24261747 'R5'
  |
  o  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  

pull --rebase update (no rebase) use proper update:

- warn about other head.

  $ cd ../a
  $ echo R6 > R6
  $ hg ci -Am R6
  adding R6
  $ cd ../c
  $ hg up 'desc(R5)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 65bc164c1d9b
  nothing to rebase - updating instead
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "65bc164c1d9b: R6"
  1 other heads for branch "default"
  $ hg tglog
  @  9: 65bc164c1d9b 'R6'
  |
  | o  8: 6dc0ea5dcf55 'L2'
  | |
  | o  7: 864e0a2d2614 'L1'
  |/
  o  6: 88dd24261747 'R5'
  |
  o  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'
  

Multiple pre-existing heads on the branch
-----------------------------------------

Pull bring content, but nothing on the current branch, we should not consider
pre-existing heads.

  $ cd ../a
  $ hg branch unrelatedbranch
  marked working directory as branch unrelatedbranch
  (branches are permanent and global, did you want a bookmark?)
  $ echo B1 > B1
  $ hg commit -Am B1
  adding B1
  $ cd ../c
  $ hg up 'desc(L2)'
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 39c381359968
  nothing to rebase

There is two local heads and we pull a third one.
The second local head should not confuse the `hg pull rebase`.

  $ hg up 'desc(R6)'
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo M1 > M1
  $ hg commit -Am M1
  adding M1
  $ cd ../a
  $ hg up 'desc(R6)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo R7 > R7
  $ hg commit -Am R7
  adding R7
  $ cd ../c
  $ hg up 'desc(L2)'
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg pull --rebase
  pulling from $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets f7d3e42052f9
  rebasing 7:864e0a2d2614 "L1"
  rebasing 8:6dc0ea5dcf55 "L2"
  saved backup bundle to $TESTTMP/c/.hg/strip-backup/864e0a2d2614-2f72c89c-rebase.hg
  $ hg tglog
  @  12: 3603a865eea0 'L2'
  |
  o  11: bcc8a9cd04bf 'L1'
  |
  o  10: f7d3e42052f9 'R7'
  |
  | o  9: 41fab4eef82f 'M1'
  |/
  | o  8: 39c381359968 'B1' unrelatedbranch
  |/
  o  7: 65bc164c1d9b 'R6'
  |
  o  6: 88dd24261747 'R5'
  |
  o  5: 00e3b7781125 'R4'
  |
  o  4: 770a61882ace 'R3'
  |
  o  3: 31cd3a05214e 'R2'
  |
  o  2: 77ae9631bcca 'R1'
  |
  o  1: 783333faa078 'C2'
  |
  o  0: 05d58a0c15dd 'C1'