--- a/CHANGELOG	Tue Jun 04 10:07:08 2019 +0200
+++ b/CHANGELOG	Mon May 27 03:42:35 2019 +0200
@@ -17,6 +17,7 @@
     (Make sure your servers are configured to use the obshashrange one.
     It is available in evolve 7.2 and above.)
   * topic: drop the b# alias. It conflicted with normal hashes.
+  * topic: add a `experimental.topic.allow-publish` option (default: True)
 
 8.5.1 -- 2019-04-23
 -------------------

--- a/hgext3rd/topic/__init__.py	Tue Jun 04 10:07:08 2019 +0200
+++ b/hgext3rd/topic/__init__.py	Mon May 27 03:42:35 2019 +0200
@@ -104,6 +104,12 @@
 In addition, the topic extension adds a ``--publish`` flag on :hg:`push`. When
 used, the pushed revisions are published if the push succeeds. It also applies
 to common revisions selected by the push.
+
+One can prevent any publishing to happens in a repository using::
+
+    [experimental]
+    topic.allow-publish = no
+
 """
 
 from __future__ import absolute_import
@@ -205,6 +211,9 @@
     configitem('experimental', 'topic.publish-bare-branch',
                default=False,
     )
+    configitem('experimental', 'topic.allow-publish',
+               default=configitems.dynamicdefault,
+    )
     configitem('_internal', 'keep-topic',
                default=False,
     )
@@ -496,6 +505,23 @@
                     flow.publishbarebranch(repo, tr2)
                     origclose()
                 tr.close = close
+            allow_publish = self.ui.configbool('experimental',
+                                               'topic.allow-publish',
+                                               True)
+            if not allow_publish:
+                if util.safehasattr(tr, 'validator'): # hg <= 4.7
+                    origvalidator = tr.validator
+                else:
+                    origvalidator = tr._validator
+
+                def validator(tr2):
+                    repo = reporef()
+                    flow.reject_publish(repo, tr2)
+                    return origvalidator(tr2)
+                if util.safehasattr(tr, 'validator'): # hg <= 4.7
+                    tr.validator = validator
+                else:
+                    tr._validator = validator
 
             # real transaction start
             ct = self.currenttopic

--- a/hgext3rd/topic/flow.py	Tue Jun 04 10:07:08 2019 +0200
+++ b/hgext3rd/topic/flow.py	Mon May 27 03:42:35 2019 +0200
@@ -55,6 +55,19 @@
         else:
             repo.ui.warn(_("unknown 'topic-mode.server': %s\n" % mode))
 
+def reject_publish(repo, tr):
+    """prevent a transaction to be publish anything"""
+    published = set()
+    for r, (o, n) in tr.changes['phases'].items():
+        if n == phases.public:
+            published.add(r)
+    if published:
+        r = min(published)
+        msg = "rejecting publishing of changeset %s" % repo[r]
+        if len(published) > 1:
+            msg += ' and %d others' % (len(published) - 1)
+        raise error.Abort(msg)
+
 def wrappush(orig, repo, remote, *args, **kwargs):
     """interpret the --publish flag and pass it to the push operation"""
     newargs = kwargs.copy()

--- a/tests/test-topic-flow-publish-bare.t	Tue Jun 04 10:07:08 2019 +0200
+++ b/tests/test-topic-flow-publish-bare.t	Mon May 27 03:42:35 2019 +0200
@@ -294,3 +294,30 @@
   |/
   o  0:ea207398892e ROOT public default
   
+
+Checking the option to prevent publishing
+=========================================
+
+Alone the option is a bit too restrictive to be useful. However combined with
+other tooling or extensions is can become an important permission tool.
+
+  $ hg log -r 'draft()'
+  changeset:   8:858be9a8daaf
+  topic:       bar
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     c_dH0
+  
+  changeset:   10:abb5c84eb9e9
+  topic:       bar
+  parent:      8:858be9a8daaf
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     c_dJ0
+  
+  $ hg phase --public -r 8 --config experimental.topic.allow-publish=no
+  abort: rejecting publishing of changeset 858be9a8daaf
+  [255]
+  $ hg phase --public -r 10 --config experimental.topic.allow-publish=no
+  abort: rejecting publishing of changeset 858be9a8daaf and 1 others
+  [255]

--- a/tests/test-topic.t	Tue Jun 04 10:07:08 2019 +0200
+++ b/tests/test-topic.t	Mon May 27 03:42:35 2019 +0200
@@ -115,6 +115,10 @@
   used, the pushed revisions are published if the push succeeds. It also applies
   to common revisions selected by the push.
   
+  One can prevent any publishing to happens in a repository using
+  
+      [experimental] topic.allow-publish = no
+  
   list of commands:
   
    stack         list all changesets in a topic and other information