$ cat <<EOF >> $HGRCPATH

  > [experimental]

  > evolution = true

  > 

  > [extensions]

  > notify =

  > hooklib =

  > 

  > [phases]

  > publish = False

  > 

  > [notify]

  > sources = pull

  > diffstat = False

  > messageidseed = example

  > domain = example.com

  > 

  > [reposubs]

  > * = baz

  > EOF

  $ hg init a

  $ hg --cwd a debugbuilddag +2

  $ hg init b

  $ cat <<EOF >> b/.hg/hgrc

  > [hooks]

  > incoming.notify = python:hgext.notify.hook

  > txnclose.changeset_obsoleted = python:hgext.hooklib.changeset_obsoleted.hook

  > EOF

  $ hg --cwd b pull ../a | "$PYTHON" $TESTDIR/unwrap-message-id.py

  pulling from ../a

  requesting all changes

  adding changesets

  adding manifests

  adding file changes

  added 2 changesets with 0 changes to 0 files

  new changesets 1ea73414a91b:66f7d451a68b (2 drafts)

  MIME-Version: 1.0

  Content-Type: text/plain; charset="us-ascii"

  Content-Transfer-Encoding: 7bit

  Date: * (glob)

  Subject: changeset in * (glob)

  From: debugbuilddag@example.com

  X-Hg-Notification: changeset 1ea73414a91b

  Message-Id: <hg.81c297828fd2d5afaadf2775a6a71b74143b6451dfaac09fac939e9107a50d01@example.com>

  To: baz@example.com

  changeset 1ea73414a91b in $TESTTMP/b

  details: $TESTTMP/b?cmd=changeset;node=1ea73414a91b

  description:

  	r0

  MIME-Version: 1.0

  Content-Type: text/plain; charset="us-ascii"

  Content-Transfer-Encoding: 7bit

  Date: * (glob)

  Subject: changeset in * (glob)

  From: debugbuilddag@example.com

  X-Hg-Notification: changeset 66f7d451a68b

  Message-Id: <hg.364d03da7dc13829eb779a805be7e37f54f572e9afcea7d2626856a794d3e8f3@example.com>

  To: baz@example.com

  changeset 66f7d451a68b in $TESTTMP/b

  details: $TESTTMP/b?cmd=changeset;node=66f7d451a68b

  description:

  	r1

  (run 'hg update' to get a working copy)

  $ hg --cwd a debugobsolete 1ea73414a91b0920940797d8fc6a11e447f8ea1e

  1 new obsolescence markers

  obsoleted 1 changesets

  1 new orphan changesets

  $ hg --cwd a push ../b --hidden | "$PYTHON" $TESTDIR/unwrap-message-id.py

  1 new orphan changesets

  pushing to ../b

  searching for changes

  no changes found

  1 new obsolescence markers

  obsoleted 1 changesets

  Subject: changeset abandoned

  In-reply-to: <hg.81c297828fd2d5afaadf2775a6a71b74143b6451dfaac09fac939e9107a50d01@example.com>

  Message-Id: <hg.d6329e9481594f0f3c8a84362b3511318bfbce50748ab1123f909eb6fbcab018@example.com>

  Date: * (glob)

  From: test@example.com

  To: baz@example.com

  This changeset has been abandoned.

Check that known changesets with known successors do not result in a mail.

  $ hg init c

  $ hg init d

  $ cat <<EOF >> d/.hg/hgrc

  > [hooks]

  > incoming.notify = python:hgext.notify.hook

  > txnclose.changeset_obsoleted = python:hgext.hooklib.changeset_obsoleted.hook

  > EOF

  $ hg --cwd c debugbuilddag '.:parent.*parent'

  $ hg --cwd c push ../d -r 1

  pushing to ../d

  searching for changes

  adding changesets

  adding manifests

  adding file changes

  added 2 changesets with 0 changes to 0 files

  $ hg --cwd c debugobsolete $(hg --cwd c log -T '{node}' -r 1) $(hg --cwd c log -T '{node}' -r 2)

  1 new obsolescence markers

  obsoleted 1 changesets

  $ hg --cwd c push ../d | "$PYTHON" $TESTDIR/unwrap-message-id.py

  pushing to ../d

  searching for changes

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 0 changes to 0 files (+1 heads)

  1 new obsolescence markers

  obsoleted 1 changesets