tests/test-notify-changegroup.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 <<EOF >> $HGRCPATH
  > [extensions]
  > notify=
  > 
  > [hooks]
  > changegroup.notify = python:hgext.notify.hook
  > 
  > [notify]
  > sources = push
  > diffstat = False
  > maxsubject = 10
  > 
  > [usersubs]
  > foo@bar = *
  > 
  > [reposubs]
  > * = baz
  > EOF
  $ hg init a

clone

  $ hg --traceback clone a b
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a > b/a

commit

  $ hg --traceback --cwd b commit -Ama
  adding a
  $ echo a >> b/a

commit

  $ hg --traceback --cwd b commit -Amb

push

  $ hg --traceback --cwd b push ../a 2>&1 |
  >     "$PYTHON" -c 'from __future__ import print_function ; import sys,re; print(re.sub("\n\t", " ", sys.stdin.read()), end="")'
  pushing to ../a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Date: * (glob)
  Subject: * (glob)
  From: test
  X-Hg-Notification: changeset cb9a9f314b8b
  Message-Id: <*> (glob)
  To: baz, foo@bar
  
  changeset cb9a9f314b8b in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=cb9a9f314b8b
  summary: a
  
  changeset ba677d0156c1 in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=ba677d0156c1
  summary: b
  
  diffs (6 lines):
  
  diff -r 000000000000 -r ba677d0156c1 a
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,2 @@
  +a
  +a
  $ hg --cwd a rollback
  repository tip rolled back to revision -1 (undo push)

unbundle with unrelated source

  $ hg --cwd b bundle ../test.hg ../a
  searching for changes
  2 changesets found
  $ hg --cwd a unbundle ../test.hg
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets cb9a9f314b8b:ba677d0156c1 (2 drafts)
  (run 'hg update' to get a working copy)
  $ hg --cwd a rollback
  repository tip rolled back to revision -1 (undo unbundle)

unbundle with correct source

  $ hg --config notify.sources=unbundle --cwd a unbundle ../test.hg 2>&1 |
  >     "$PYTHON" -c 'from __future__ import print_function ; import sys,re; print(re.sub("\n\t", " ", sys.stdin.read()), end="")'
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets cb9a9f314b8b:ba677d0156c1 (2 drafts)
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Date: * (glob)
  Subject: * (glob)
  From: test
  X-Hg-Notification: changeset cb9a9f314b8b
  Message-Id: <*> (glob)
  To: baz, foo@bar
  
  changeset cb9a9f314b8b in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=cb9a9f314b8b
  summary: a
  
  changeset ba677d0156c1 in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=ba677d0156c1
  summary: b
  
  diffs (6 lines):
  
  diff -r 000000000000 -r ba677d0156c1 a
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,2 @@
  +a
  +a
  (run 'hg update' to get a working copy)

Check that using the first committer as the author of a changeset works:
Check that the config option works.
Check that the first committer is indeed used for "From:".
Check that the merge user is NOT used for "From:"

Create new file

  $ echo a > b/b
  $ echo b >> b/b
  $ echo c >> b/b
  $ hg --traceback --cwd b commit -Amnewfile -u committer_1
  adding b

commit as one user

  $ echo x > b/b
  $ echo b >> b/b
  $ echo c >> b/b
  $ hg --traceback --cwd b commit -Amx -u committer_2

commit as other user, change file so we can do an (automatic) merge

  $ hg --cwd b up 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a > b/b
  $ echo b >> b/b
  $ echo y >> b/b
  $ hg --traceback --cwd b commit -Amy -u committer_3
  created new head

merge as a different user

  $ hg --cwd b merge --config notify.fromauthor=True
  merging b
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg --traceback --cwd b commit -Am "merged"

push

  $ hg --traceback --cwd b --config notify.fromauthor=True push ../a 2>&1 |
  >     "$PYTHON" -c 'from __future__ import print_function ; import sys,re; print(re.sub("\n\t", " ", sys.stdin.read()), end="")'
  pushing to ../a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Date: * (glob)
  Subject: * (glob)
  From: committer_1
  X-Hg-Notification: changeset 84e487dddc58
  Message-Id: <*> (glob)
  To: baz, foo@bar
  
  changeset 84e487dddc58 in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=84e487dddc58
  summary: newfile
  
  changeset b29c7a2b6b0c in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=b29c7a2b6b0c
  summary: x
  
  changeset 0957c7d64886 in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=0957c7d64886
  summary: y
  
  changeset 485b4e6b0249 in $TESTTMP/a
  details: $TESTTMP/a?cmd=changeset;node=485b4e6b0249
  summary: merged
  
  diffs (7 lines):
  
  diff -r ba677d0156c1 -r 485b4e6b0249 b
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/b	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,3 @@
  +x
  +b
  +y
  $ hg --cwd a rollback
  repository tip rolled back to revision 1 (undo push)