# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@ens-lyon.org>
# Date 1471197478 -7200
# Node ID 03d6b685c16a246818f50781086a4431a3849170
# Parent  2a07df82358882e55409280c9d49f76777412ab7
topic: list the number of 'behind' changeset when --verbose is used

Displaying more information in the topic list is useful, we continue with the
number of 'behind' changesets. This 'behind' count the number of new changesets on
the default rebase destination. This will highlight topics that need rebasing.

diff -r 2a07df823588 -r 03d6b685c16a hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Mon Aug 15 00:19:44 2016 +0200
+++ b/hgext3rd/topic/__init__.py	Sun Aug 14 19:57:58 2016 +0200
@@ -47,6 +47,8 @@
 colortable = {'topic.active': 'green',
               'topic.list.troubledcount': 'red',
               'topic.list.headcount.multiple': 'yellow',
+              'topic.list.behindcount': 'cyan',
+              'topic.list.behinderror': 'red',
               'topic.stack.index': 'yellow',
               'topic.stack.state.base': 'dim',
               'topic.stack.state.clean': 'green',
@@ -307,6 +309,16 @@
                 fm.write('headcount', '%d heads',
                          data['headcount'],
                          label='topic.list.headcount.multiple')
+            if 0 < data['behindcount']:
+                fm.plain(', ')
+                fm.write('behindcount', '%d behind',
+                         data['behindcount'],
+                         label='topic.list.behindcount')
+            elif -1 == data['behindcount']:
+                fm.plain(', ')
+                fm.write('behinderror', '%s',
+                         _('ambiguous destination'),
+                         label='topic.list.behinderror')
             fm.plain(')')
         fm.plain('\n')
     fm.end()
diff -r 2a07df823588 -r 03d6b685c16a hgext3rd/topic/stack.py
--- a/hgext3rd/topic/stack.py	Mon Aug 15 00:19:44 2016 +0200
+++ b/hgext3rd/topic/stack.py	Sun Aug 14 19:57:58 2016 +0200
@@ -4,6 +4,7 @@
 # GNU General Public License version 2 or any later version.
 from mercurial.i18n import _
 from mercurial import (
+    destutil,
     error,
     node,
 )
@@ -69,6 +70,7 @@
     :changesetcount: number of non-obsolete changesets in the stack
     :troubledcount: number on troubled changesets
     :headcount: number of heads on the topic
+    :behindcount: number of changeset on rebase destination
     """
     data = {}
     revs = repo.revs("topic(%s) - obsolete()", topic)
@@ -76,6 +78,19 @@
     data['troubledcount'] = len([r for r in revs if repo[r].troubled()])
     deps, rdeps = builddependencies(repo, revs)
     data['headcount'] = len([r for r in revs if not rdeps[r]])
+    data['behindcount'] = 0
+    if revs:
+        minroot = [min(r for r in revs if not deps[r])]
+        try:
+            dest = destutil.destmerge(repo, action='rebase',
+                                      sourceset=minroot,
+                                      onheadcheck=False)
+            data['behindcount'] = len(repo.revs("only(%d, %ld)", dest,
+                                                minroot))
+        except error.NoMergeDestAbort:
+            data['behindcount'] = 0
+        except error.ManyMergeDestAbort:
+            data['behindcount'] = -1
 
     return data
 
diff -r 2a07df823588 -r 03d6b685c16a tests/test-topic-list.t
--- a/tests/test-topic-list.t	Mon Aug 15 00:19:44 2016 +0200
+++ b/tests/test-topic-list.t	Sun Aug 14 19:57:58 2016 +0200
@@ -174,9 +174,9 @@
 
   $ hg topic --verbose
      bar	(5 changesets, 1 troubled, 2 heads)
-     baz	(2 changesets)
-   * foo	(2 changesets)
-     fuz	(3 changesets, 2 troubled)
+     baz	(2 changesets, 2 behind)
+   * foo	(2 changesets, ambiguous destination)
+     fuz	(3 changesets, 2 troubled, 1 behind)
 
 json
 
@@ -213,16 +213,19 @@
    },
    {
     "active": false,
+    "behindcount": 2,
     "changesetcount": 2,
     "topic": "baz"
    },
    {
     "active": true,
+    "behinderror": "ambiguous destination",
     "changesetcount": 2,
     "topic": "foo"
    },
    {
     "active": false,
+    "behindcount": 1,
     "changesetcount": 3,
     "topic": "fuz",
     "troubledcount": 2