# HG changeset patch
# User Aurélien Campéas
# Date 1506091297 -7200
# Node ID 4746b92cc1f881df1079dc0758e630028605c174
# Parent  f63c97c01f92d484674c5c810a60ed7f73fc0fa1
topics/ui: signal when an operation entails voiding a topic

Typical situations may include:

* publish
* push (to publishing server)
* pull
* fold

diff -r f63c97c01f92 -r 4746b92cc1f8 hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Tue Sep 26 12:29:15 2017 +0200
+++ b/hgext3rd/topic/__init__.py	Fri Sep 22 16:41:37 2017 +0200
@@ -54,6 +54,7 @@
 
 import re
 import time
+import weakref
 
 from mercurial.i18n import _
 from mercurial import (
@@ -311,6 +312,24 @@
                 peer.__class__ = topicpeer
             return peer
 
+        def transaction(self, *a, **k):
+            tr = super(topicrepo, self).transaction(*a, **k)
+
+            reporef = weakref.ref(self)
+
+            def currenttopicempty(tr):
+                # check active topic emptyness
+                ct = self.currenttopic
+                if not ct:
+                    return
+                repo = reporef()
+                empty = stack.stackdata(repo, topic=ct)['changesetcount'] == 0
+                if empty:
+                    ui.status('active topic %r is now empty\n' % ct)
+
+            tr.addpostclose('signalcurrenttopicempty', currenttopicempty)
+            return tr
+
     repo.__class__ = topicrepo
     repo._topics = None
     if util.safehasattr(repo, 'names'):
diff -r f63c97c01f92 -r 4746b92cc1f8 tests/test-topic-fold.t
--- a/tests/test-topic-fold.t	Tue Sep 26 12:29:15 2017 +0200
+++ b/tests/test-topic-fold.t	Fri Sep 22 16:41:37 2017 +0200
@@ -90,6 +90,7 @@
   o  0:3e7df3b3b17c6deb4a1c70e790782fdf17af96a7
      topics:
   $ hg fold --exact -r "(tip~1)::" -m "folded 2"
+  active topic 'myotherfeature' is now empty
   2 changesets folded
   clearing empty topic "myotherfeature"
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
diff -r f63c97c01f92 -r 4746b92cc1f8 tests/test-topic-stack.t
--- a/tests/test-topic-stack.t	Tue Sep 26 12:29:15 2017 +0200
+++ b/tests/test-topic-stack.t	Fri Sep 22 16:41:37 2017 +0200
@@ -59,6 +59,7 @@
   t2@ c_b (current)
   t1: c_a
   $ hg phase --public 'topic("other")'
+  active topic 'other' is now empty
 
 After changing the phase of all the changesets in "other" to public, the topic should still be active, but is empty. We should be better at informating the user about it and displaying good data in this case.
 
diff -r f63c97c01f92 -r 4746b92cc1f8 tests/test-topic-tutorial.t
--- a/tests/test-topic-tutorial.t	Tue Sep 26 12:29:15 2017 +0200
+++ b/tests/test-topic-tutorial.t	Fri Sep 22 16:41:37 2017 +0200
@@ -584,6 +584,7 @@
   adding file changes
   added 2 changesets with 2 changes to 1 files
   2 new obsolescence markers
+  active topic 'food' is now empty
 
   $ hg topics
    * food
diff -r f63c97c01f92 -r 4746b92cc1f8 tests/test-topic.t
--- a/tests/test-topic.t	Tue Sep 26 12:29:15 2017 +0200
+++ b/tests/test-topic.t	Fri Sep 22 16:41:37 2017 +0200
@@ -401,6 +401,7 @@
   query
   tip
   $ hg phase --public narf
+  active topic 'narf' is now empty
 
 POSSIBLE BUG: narf topic stays alive even though we just made all
 narf commits public:
@@ -461,6 +462,7 @@
   adding manifests
   adding file changes
   added 3 changesets with 3 changes to 1 files
+  active topic 'query' is now empty
   (run 'hg update' to get a working copy)
   $ hg topics
    * query
@@ -474,6 +476,7 @@
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
+  active topic 'query' is now empty
   (run 'hg heads' to see heads)
   $ hg topics
      fran