# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1457980759 0
# Node ID f52c02bf47b7630e5343e4feb5d5f6fb6f115e84
# Parent  58cdf061d49aee54a674ee7b7a82c22cd387f344
stack: allow to refer to changeset using "t2" form

hg up "t0" is seen as "update to the first changeset of my current topic".
Eventually we'll drop the "t2" form in favor of the planned generic indexing
operator '.{t2}'.

diff -r 58cdf061d49a -r f52c02bf47b7 hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Tue Mar 15 17:26:57 2016 +0000
+++ b/hgext3rd/topic/__init__.py	Mon Mar 14 18:39:19 2016 +0000
@@ -12,6 +12,7 @@
 """
 import functools
 import contextlib
+import re
 
 from mercurial.i18n import _
 from mercurial import branchmap
@@ -51,7 +52,22 @@
     return self.extra().get(constants.extrakey, '')
 context.basectx.topic = _contexttopic
 
+topicrev = re.compile(r'^t\d+$')
+
+
 def _namemap(repo, name):
+    if topicrev.match(name):
+        idx = int(name[1:])
+        topic = repo.currenttopic
+        if not topic:
+            raise error.Abort(_('cannot resolve "%s": no active topic') % name)
+        revs = list(stack.getstack(repo, topic))
+        try:
+            r = revs[idx]
+        except IndexError:
+            msg = _('cannot resolve "%s": topic "%s" has only %d changesets')
+            raise error.Abort(msg % (name, topic, len(revs)))
+        return [repo[r].node()]
     return [ctx.node() for ctx in
             repo.set('not public() and extra(topic, %s)', name)]
 
diff -r 58cdf061d49a -r f52c02bf47b7 hgext3rd/topic/discovery.py
--- a/hgext3rd/topic/discovery.py	Tue Mar 15 17:26:57 2016 +0000
+++ b/hgext3rd/topic/discovery.py	Mon Mar 14 18:39:19 2016 +0000
@@ -107,5 +107,3 @@
     if repo.peer().capable('topics'):
         caps.append('topics')
     return caps
-
-
diff -r 58cdf061d49a -r f52c02bf47b7 hgext3rd/topic/stack.py
--- a/hgext3rd/topic/stack.py	Tue Mar 15 17:26:57 2016 +0000
+++ b/hgext3rd/topic/stack.py	Mon Mar 14 18:39:19 2016 +0000
@@ -8,7 +8,7 @@
 from mercurial import extensions
 from mercurial import obsolete
 
-def _getstack(repo, topic):
+def getstack(repo, topic):
     # XXX need sorting
     trevs = repo.revs("topic(%s) - obsolete()", topic)
     return _orderrevs(repo, trevs)
@@ -18,7 +18,7 @@
         topic = repo.currenttopic
     if not topic:
         raise error.Abort(_('no active topic to list'))
-    for idx, r in enumerate(_getstack(repo, topic)):
+    for idx, r in enumerate(getstack(repo, topic)):
         # super crude initial version
         l = "%d: %s\n" % (idx, repo[r].description().splitlines()[0])
         ui.write(l)
diff -r 58cdf061d49a -r f52c02bf47b7 tests/test-topic-stack.t
--- a/tests/test-topic-stack.t	Tue Mar 15 17:26:57 2016 +0000
+++ b/tests/test-topic-stack.t	Mon Mar 14 18:39:19 2016 +0000
@@ -69,12 +69,23 @@
   abort: no active topic to list
   [255]
 
+Test "t#" reference
+-------------------
+
+
+  $ hg up t1
+  abort: cannot resolve "t1": no active topic
+  [255]
+  $ hg topic foo
+  $ hg up t42
+  abort: cannot resolve "t42": topic "foo" has only 4 changesets
+  [255]
+  $ hg up t1
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+
 Case with some of the topic unstable
 ------------------------------------
 
-  $ hg up 'desc(c_d)'
-  switching to topic foo
-  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ echo bbb > ddd
   $ hg commit --amend
   $ hg log -G