From upstream https://bz.mercurial-scm.org/show_bug.cgi?id=4943

# Files opened in a+ mode have inconsistent behavior on various
# platforms. Windows requires that a file positioning call be made
# when the file handle transitions between reads and writes. See
# 3686fa2b8eee and the mixedfilemodewrapper in windows.py. On other
# platforms, Python or the platform itself can be buggy. Some versions
# of Solaris have been observed to not append at the end of the file
# if the file was seeked to before the end. See issue4943 for more.
#
# We work around this issue by inserting a seek() before writing.
# Note: This is likely not necessary on Python 3.

bump PKGREVISION
okay'd by wiz@

3 files changed, 37 insertions, 2 deletions

diff --git a/devel/py-mercurial/Makefile b/devel/py-mercurial/Makefile
index 5a2f209f3d2..a6dff3b42c3 100644
--- a/devel/py-mercurial/Makefile
+++ b/devel/py-mercurial/Makefile
@@ -1,7 +1,8 @@
-# $NetBSD: Makefile,v 1.7 2015/09/02 16:52:37 wiz Exp $
+# $NetBSD: Makefile,v 1.8 2015/12/21 13:19:17 richard Exp $
 
 DISTNAME=	mercurial-${VERSION}
 PKGNAME=	${PYPKGPREFIX}-${DISTNAME}
+PKGREVISION=	1
 CATEGORIES=	devel scm
 MASTER_SITES=	https://mercurial.selenic.com/release/
 
diff --git a/devel/py-mercurial/distinfo b/devel/py-mercurial/distinfo
index 1f8aebe7982..a7e01a89ead 100644
--- a/devel/py-mercurial/distinfo
+++ b/devel/py-mercurial/distinfo
@@ -1,6 +1,7 @@
-$NetBSD: distinfo,v 1.27 2015/12/05 11:22:32 wiz Exp $
+$NetBSD: distinfo,v 1.28 2015/12/21 13:19:17 richard Exp $
 
 SHA1 (mercurial-3.6.2.tar.gz) = 1dbf5d9d42f70f1fb0b26f8e659a1b7879bc1533
 RMD160 (mercurial-3.6.2.tar.gz) = 0671aa8429befbc9b049cb640a54d4c810103f56
 SHA512 (mercurial-3.6.2.tar.gz) = 2ad780174a30c39a1482d597466523a133b8c62a3a0eb9ac3b183082e279fc624998a9ffa520abafe5f7afc7d9f4600f443ad4dfa1003bd7fdc6b713040091ed
 Size (mercurial-3.6.2.tar.gz) = 4518349 bytes
+SHA1 (patch-mercurial_revlog.py) = 2c6ba5325480d6a6c025e00fe7903eb007069e1f
diff --git a/devel/py-mercurial/patches/patch-mercurial_revlog.py b/devel/py-mercurial/patches/patch-mercurial_revlog.py
new file mode 100644
index 00000000000..4fc7a18011c
--- /dev/null
+++ b/devel/py-mercurial/patches/patch-mercurial_revlog.py
@@ -0,0 +1,33 @@
+$NetBSD: patch-mercurial_revlog.py,v 1.1 2015/12/21 13:19:17 richard Exp $
+https://bz.mercurial-scm.org/show_bug.cgi?id=4943
+--- mercurial/revlog.py.orig	2015-12-02 02:18:26.000000000 +0000
++++ mercurial/revlog.py
+@@ -13,6 +13,7 @@ and O(changes) merge between branches.
+ 
+ # import stuff from node for others to import from revlog
+ import collections
++import os
+ from node import bin, hex, nullid, nullrev
+ from i18n import _
+ import ancestor, mdiff, parsers, error, util, templatefilters
+@@ -1426,6 +1427,20 @@ class revlog(object):
+         return node
+ 
+     def _writeentry(self, transaction, ifh, dfh, entry, data, link, offset):
++        # Files opened in a+ mode have inconsistent behavior on various
++        # platforms. Windows requires that a file positioning call be made
++        # when the file handle transitions between reads and writes. See
++        # 3686fa2b8eee and the mixedfilemodewrapper in windows.py. On other
++        # platforms, Python or the platform itself can be buggy. Some versions
++        # of Solaris have been observed to not append at the end of the file
++        # if the file was seeked to before the end. See issue4943 for more.
++        #
++        # We work around this issue by inserting a seek() before writing.
++        # Note: This is likely not necessary on Python 3.
++        ifh.seek(0, os.SEEK_END)
++        if dfh:
++            dfh.seek(0, os.SEEK_END)
++
+         curr = len(self) - 1
+         if not self._inline:
+             transaction.add(self.datafile, offset)