diff --git a/hgext/hooklib/changeset_obsoleted.py b/hgext/hooklib/changeset_obsoleted.py
--- a/hgext/hooklib/changeset_obsoleted.py
+++ b/hgext/hooklib/changeset_obsoleted.py
@@ -122,10 +122,18 @@
         )
 
 
+def has_successor(repo, rev):
+    return any(
+        r for r in obsutil.allsuccessors(repo.obsstore, [rev]) if r != rev
+    )
+
+
 def hook(ui, repo, hooktype, node=None, **kwargs):
-    if hooktype != b"pretxnclose":
+    if hooktype != b"txnclose":
         raise error.Abort(
             _(b'Unsupported hook type %r') % pycompat.bytestr(hooktype)
         )
-    for rev in obsutil.getobsoleted(repo, repo.currenttransaction()):
-        _report_commit(ui, repo, repo.unfiltered()[rev])
+    for rev in obsutil.getobsoleted(repo, changes=kwargs['changes']):
+        ctx = repo.unfiltered()[rev]
+        if not has_successor(repo, ctx.node()):
+            _report_commit(ui, repo, ctx)
diff --git a/mercurial/obsutil.py b/mercurial/obsutil.py
--- a/mercurial/obsutil.py
+++ b/mercurial/obsutil.py
@@ -13,6 +13,7 @@
 from . import (
     diffutil,
     encoding,
+    error,
     node as nodemod,
     phases,
     pycompat,
@@ -481,14 +482,23 @@
     return effects
 
 
-def getobsoleted(repo, tr):
-    """return the set of pre-existing revisions obsoleted by a transaction"""
+def getobsoleted(repo, tr=None, changes=None):
+    """return the set of pre-existing revisions obsoleted by a transaction
+
+    Either the transaction or changes item of the transaction (for hooks)
+    must be provided, but not both.
+    """
+    if (tr is None) == (changes is None):
+        e = b"exactly one of tr and changes must be provided"
+        raise error.ProgrammingError(e)
     torev = repo.unfiltered().changelog.index.get_rev
     phase = repo._phasecache.phase
     succsmarkers = repo.obsstore.successors.get
     public = phases.public
-    addedmarkers = tr.changes[b'obsmarkers']
-    origrepolen = tr.changes[b'origrepolen']
+    if changes is None:
+        changes = tr.changes
+    addedmarkers = changes[b'obsmarkers']
+    origrepolen = changes[b'origrepolen']
     seenrevs = set()
     obsoleted = set()
     for mark in addedmarkers:
diff --git a/tests/test-hooklib-changeset_obsoleted.t b/tests/test-hooklib-changeset_obsoleted.t
--- a/tests/test-hooklib-changeset_obsoleted.t
+++ b/tests/test-hooklib-changeset_obsoleted.t
@@ -24,7 +24,7 @@
   $ cat <<EOF >> b/.hg/hgrc
   > [hooks]
   > incoming.notify = python:hgext.notify.hook
-  > pretxnclose.changeset_obsoleted = python:hgext.hooklib.changeset_obsoleted.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
@@ -72,6 +72,8 @@
   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>
@@ -80,5 +82,33 @@
   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