view tests/test-narrow-exchange-merges.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

  $ . "$TESTDIR/narrow-library.sh"

create full repo

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ mkdir inside
  $ echo 1 > inside/f
  $ hg commit -Aqm 'initial inside'

  $ mkdir outside
  $ echo 1 > outside/f
  $ hg commit -Aqm 'initial outside'

  $ echo 2a > outside/f
  $ hg commit -Aqm 'outside 2a'
  $ echo 3 > inside/f
  $ hg commit -Aqm 'inside 3'
  $ echo 4a > outside/f
  $ hg commit -Aqm 'outside 4a'
  $ hg update '.~3'
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo 2b > outside/f
  $ hg commit -Aqm 'outside 2b'
  $ echo 3 > inside/f
  $ hg commit -Aqm 'inside 3'
  $ echo 4b > outside/f
  $ hg commit -Aqm 'outside 4b'
  $ hg update '.~3'
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo 2c > outside/f
  $ hg commit -Aqm 'outside 2c'
  $ echo 3 > inside/f
  $ hg commit -Aqm 'inside 3'
  $ echo 4c > outside/f
  $ hg commit -Aqm 'outside 4c'
  $ hg update '.~3'
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo 2d > outside/f
  $ hg commit -Aqm 'outside 2d'
  $ echo 3 > inside/f
  $ hg commit -Aqm 'inside 3'
  $ echo 4d > outside/f
  $ hg commit -Aqm 'outside 4d'

  $ hg update -r 'desc("outside 4a")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg merge -r 'desc("outside 4b")' 2>&1 | egrep -v '(warning:|incomplete!)'
  merging outside/f
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  $ echo 5 > outside/f
  $ rm outside/f.orig
  $ hg resolve --mark outside/f
  (no more unresolved files)
  $ hg commit -m 'merge a/b 5'
  $ echo 6 > outside/f
  $ hg commit -Aqm 'outside 6'

  $ hg merge -r 'desc("outside 4c")' 2>&1 | egrep -v '(warning:|incomplete!)'
  merging outside/f
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  $ echo 7 > outside/f
  $ rm outside/f.orig
  $ hg resolve --mark outside/f
  (no more unresolved files)
  $ hg commit -Aqm 'merge a/b/c 7'
  $ echo 8 > outside/f
  $ hg commit -Aqm 'outside 8'

  $ hg merge -r 'desc("outside 4d")' 2>&1 | egrep -v '(warning:|incomplete!)'
  merging outside/f
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  $ echo 9 > outside/f
  $ rm outside/f.orig
  $ hg resolve --mark outside/f
  (no more unresolved files)
  $ hg commit -Aqm 'merge a/b/c/d 9'
  $ echo 10 > outside/f
  $ hg commit -Aqm 'outside 10'

  $ echo 11 > inside/f
  $ hg commit -Aqm 'inside 11'
  $ echo 12 > outside/f
  $ hg commit -Aqm 'outside 12'

  $ hg log -G -T '{rev} {node|short} {desc}\n'
  @  21 8d874d57adea outside 12
  |
  o  20 7ef88b4dd4fa inside 11
  |
  o  19 2a20009de83e outside 10
  |
  o    18 3ac1f5779de3 merge a/b/c/d 9
  |\
  | o  17 38a9c2f7e546 outside 8
  | |
  | o    16 094aa62fc898 merge a/b/c 7
  | |\
  | | o  15 f29d083d32e4 outside 6
  | | |
  | | o    14 2dc11382541d merge a/b 5
  | | |\
  o | | |  13 27d07ef97221 outside 4d
  | | | |
  o | | |  12 465567bdfb2d inside 3
  | | | |
  o | | |  11 d1c61993ec83 outside 2d
  | | | |
  | o | |  10 56859a8e33b9 outside 4c
  | | | |
  | o | |  9 bb96a08b062a inside 3
  | | | |
  | o | |  8 b844052e7b3b outside 2c
  |/ / /
  | | o  7 9db2d8fcc2a6 outside 4b
  | | |
  | | o  6 6418167787a6 inside 3
  | | |
  +---o  5 77344f344d83 outside 2b
  | |
  | o  4 9cadde08dc9f outside 4a
  | |
  | o  3 019ef06f125b inside 3
  | |
  | o  2 75e40c075a19 outside 2a
  |/
  o  1 906d6c682641 initial outside
  |
  o  0 9f8e82b51004 initial inside
  

Now narrow clone this and get a hopefully correct graph

  $ cd ..
  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 14 changesets with 3 changes to 1 files
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow

To make updating the tests easier, we print the emitted nodes
sorted. This makes it easier to identify when the same node structure
has been emitted, just in a different order.

  $ hg log -T '{if(ellipsis,"...")}{node|short} {p1node|short} {p2node|short} {desc}\n' | sort
  ...094aa62fc898 6418167787a6 bb96a08b062a merge a/b/c 7
  ...2a20009de83e 019ef06f125b 3ac1f5779de3 outside 10
  ...3ac1f5779de3 465567bdfb2d 094aa62fc898 merge a/b/c/d 9
  ...75e40c075a19 9f8e82b51004 000000000000 outside 2a
  ...77344f344d83 9f8e82b51004 000000000000 outside 2b
  ...8d874d57adea 7ef88b4dd4fa 000000000000 outside 12
  ...b844052e7b3b 9f8e82b51004 000000000000 outside 2c
  ...d1c61993ec83 9f8e82b51004 000000000000 outside 2d
  019ef06f125b 75e40c075a19 000000000000 inside 3
  465567bdfb2d d1c61993ec83 000000000000 inside 3
  6418167787a6 77344f344d83 000000000000 inside 3
  7ef88b4dd4fa 2a20009de83e 000000000000 inside 11
  9f8e82b51004 000000000000 000000000000 initial inside
  bb96a08b062a b844052e7b3b 000000000000 inside 3

But seeing the graph is also nice:
  $ hg log -G -T '{if(ellipsis,"...")}{node|short} {desc}\n'
  @  ...8d874d57adea outside 12
  |
  o  7ef88b4dd4fa inside 11
  |
  o    ...2a20009de83e outside 10
  |\
  | o    ...3ac1f5779de3 merge a/b/c/d 9
  | |\
  | | o    ...094aa62fc898 merge a/b/c 7
  | | |\
  | o | |  465567bdfb2d inside 3
  | | | |
  | o | |  ...d1c61993ec83 outside 2d
  | | | |
  | | | o  bb96a08b062a inside 3
  | | | |
  | +---o  ...b844052e7b3b outside 2c
  | | |
  | | o  6418167787a6 inside 3
  | | |
  | | o  ...77344f344d83 outside 2b
  | |/
  o |  019ef06f125b inside 3
  | |
  o |  ...75e40c075a19 outside 2a
  |/
  o  9f8e82b51004 initial inside