# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1459754883 25200
# Node ID d9c7fced94fca96b623c06d20cc6e4c90a6225f6
# Parent  a9a1abc7dd759f272dc7e3ac01e16bd2a323cbfe
stack: prevent crash when topic is rooted on nullid

We exclude null from displayed base. This was causing a crash when trying to
display its description (we'll still have to handle the empty description case,
but it is now less urgent).

diff -r a9a1abc7dd75 -r d9c7fced94fc hgext3rd/topic/stack.py
--- a/hgext3rd/topic/stack.py	Mon Apr 04 00:22:20 2016 -0700
+++ b/hgext3rd/topic/stack.py	Mon Apr 04 00:28:03 2016 -0700
@@ -6,6 +6,7 @@
 from mercurial.i18n import _
 from mercurial import (
     error,
+    node,
     obsolete,
 )
 
@@ -27,7 +28,7 @@
         p1 = ctx.p1()
         if p1.obsolete():
             p1 = repo[_singlesuccessor(repo, p1)]
-        if p1.rev() != prev:
+        if p1.rev() != prev and p1.node() != node.nullid:
             entries.append((None, p1))
         entries.append((idx, ctx))
         prev = r
diff -r a9a1abc7dd75 -r d9c7fced94fc tests/test-topic-stack.t
--- a/tests/test-topic-stack.t	Mon Apr 04 00:22:20 2016 -0700
+++ b/tests/test-topic-stack.t	Mon Apr 04 00:28:03 2016 -0700
@@ -46,7 +46,19 @@
   o  0 default {other} draft c_a
   
 
+Check that topic without any parent does not crash --list
+---------------------------------------------------------
+
+  $ hg up other
+  switching to topic other
+  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
+  $ hg topic --list
+  t2@ c_b (current)
+  t1: c_a
   $ hg phase --public 'topic("other")'
+  $ hg up foo
+  switching to topic foo
+  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 Simple test
 -----------