--- a/CHANGELOG	Sat Mar 21 15:04:18 2020 +0100
+++ b/CHANGELOG	Mon Apr 06 05:05:07 2020 +0200
@@ -1,13 +1,14 @@
 Changelog
 =========
 
-9.3.0 - in progress
+9.3.1 - in progress
 -------------------
 
   * obsexchange: avoid sending too large request to http server
   * obsdiscovery: server no longer aborts with a 500 error if client sends a
     request without obscommon
   * evolve: improved behavior when evolving above the result of a split
+  * topic: fix auto-publish=abort with server that auto-publishes bare branches
 
 9.3.0 -- 2020-03-04
 -------------------

--- a/hgext3rd/topic/__init__.py	Sat Mar 21 15:04:18 2020 +0100
+++ b/hgext3rd/topic/__init__.py	Mon Apr 06 05:05:07 2020 +0200
@@ -140,6 +140,7 @@
     commands,
     context,
     error,
+    exchange,
     extensions,
     hg,
     localrepo,
@@ -380,6 +381,8 @@
     extensions.wrapfunction(context.workingctx, '__init__', wrapinit)
     # Wrap changelog.add to drop empty topic
     extensions.wrapfunction(changelog.changelog, 'add', wrapadd)
+    # Make exchange._checkpublish handle experimental.topic.publish-bare-branch
+    extensions.wrapfunction(exchange, '_checkpublish', flow.replacecheckpublish)
 
     server.setupserver(ui)
 
@@ -401,6 +404,9 @@
         def _restrictcapabilities(self, caps):
             caps = super(topicrepo, self)._restrictcapabilities(caps)
             caps.add(b'topics')
+            if self.ui.configbool(b'experimental',
+                                  b'topic.publish-bare-branch'):
+                caps.add(b'ext-topics-publish=auto')
             return caps
 
         def commit(self, *args, **kwargs):

--- a/hgext3rd/topic/flow.py	Sat Mar 21 15:04:18 2020 +0100
+++ b/hgext3rd/topic/flow.py	Mon Apr 06 05:05:07 2020 +0200
@@ -108,3 +108,57 @@
                             extendpushoperation)
     extensions.wrapfunction(exchange, '_pushdiscoveryphase', wrapphasediscovery)
     exchange.pushdiscoverymapping[b'phase'] = exchange._pushdiscoveryphase
+
+def replacecheckpublish(orig, pushop):
+    listkeys = exchange.listkeys
+    repo = pushop.repo
+    ui = repo.ui
+    behavior = ui.config(b'experimental', b'auto-publish')
+    if pushop.publish or behavior not in (b'warn', b'confirm', b'abort'):
+        return
+
+    # possible modes are:
+    #
+    # none -> nothing is published on push
+    # all  -> everything is published on push
+    # auto -> only changeset without topic are published on push
+    #
+    # Unknown mode is assumed "all" for safety.
+    #
+    # TODO: do a wider brain storming about mode names.
+
+    mode = b'all'
+    remotephases = listkeys(pushop.remote, b'phases')
+    if not remotephases.get(b'publishing', False):
+        mode = b'none'
+        for c in pushop.remote.capabilities():
+            if c.startswith(b'ext-topics-publish'):
+                mode = c.split(b'=', 1)[1]
+                break
+    if mode == b'none':
+        return
+
+    if pushop.revs is None:
+        published = repo.filtered(b'served').revs(b'not public()')
+    else:
+        published = repo.revs(b'::%ln - public()', pushop.revs)
+    if mode == b'auto':
+        published = repo.revs(b'%ld::(%ld - topic())', published, published)
+    if published:
+        if behavior == b'warn':
+            ui.warn(
+                _(b'%i changesets about to be published\n') % len(published)
+            )
+        elif behavior == b'confirm':
+            if ui.promptchoice(
+                _(b'push and publish %i changesets (yn)?$$ &Yes $$ &No')
+                % len(published)
+            ):
+                raise error.Abort(_(b'user quit'))
+        elif behavior == b'abort':
+            msg = _(b'push would publish %i changesets') % len(published)
+            hint = _(
+                b"use --publish or adjust 'experimental.auto-publish'"
+                b" config"
+            )
+            raise error.Abort(msg, hint=hint)

--- a/tests/test-topic-flow-publish-bare.t	Sat Mar 21 15:04:18 2020 +0100
+++ b/tests/test-topic-flow-publish-bare.t	Mon Apr 06 05:05:07 2020 +0200
@@ -321,3 +321,43 @@
   $ hg phase --public -r 10 --config experimental.topic.allow-publish=no
   abort: rejecting publishing of changeset 858be9a8daaf and 1 others
   [255]
+
+Checking the option to prevent automatic publishing
+===================================================
+
+  $ hg up branchA
+  2 files updated, 0 files merged, 5 files removed, 0 files unresolved
+
+Trying to push changeset without topic (would publish them)
+
+  $ mkcommit c_aM0
+  $ hg debugcapabilities $TESTTMP/bare-branch-server | grep topics
+    ext-topics-publish=auto
+    topics
+  $ hg push --config experimental.auto-publish=abort -r .
+  pushing to $TESTTMP/bare-branch-server
+  abort: push would publish 1 changesets
+  (use --publish or adjust 'experimental.auto-publish' config)
+  [255]
+  $ hg push --config experimental.auto-publish=abort -r . --publish
+  pushing to $TESTTMP/bare-branch-server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+
+Pushing a changeset with topic (not publishing, no warning)
+
+  $ hg topic test-push-protection
+  marked working directory as topic: test-push-protection
+  $ mkcommit c_aL0
+  active topic 'test-push-protection' grew its first changeset
+  (see 'hg help topics' for more information)
+  $ hg push --config experimental.auto-publish=abort -r .
+  pushing to $TESTTMP/bare-branch-server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files