# HG changeset patch
# User Denis Laxalde <denis@laxalde.org>
# Date 1570732054 -7200
# Node ID 01e8eefd943406c645df4dff11871683d35848b5
# Parent  bca9d1a6c4c56143ffe4c556b595db6fe5b56ae1
py3: fix sorting of obsolete markers when building bundle

Last item of marker tuple (parents) is either None or tuple. Comparison
thus fails on Python 3 with:

  TypeError: '<' not supported between instances of 'tuple' and 'NoneType'

Fixing this by coercing None to the empty tuple when sorting markers in
exchange._getbundleobsmarkerpart().

diff -r bca9d1a6c4c5 -r 01e8eefd9434 mercurial/exchange.py
--- a/mercurial/exchange.py	Thu Oct 10 04:34:58 2019 +0200
+++ b/mercurial/exchange.py	Thu Oct 10 20:27:34 2019 +0200
@@ -2567,7 +2567,8 @@
             heads = repo.heads()
         subset = [c.node() for c in repo.set(b'::%ln', heads)]
         markers = repo.obsstore.relevantmarkers(subset)
-        markers = sorted(markers)
+        # last item of marker tuple ('parents') may be None or a tuple
+        markers = sorted(markers, key=lambda m: m[:-1] + (m[-1] or (),))
         bundle2.buildobsmarkerspart(bundler, markers)