From d2c91253e64e144d17d0f5a0ce9c72661c43a29c Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 4 Jul 2015 22:01:39 +0100
Subject: dgit: Set up a merge driver for debian/changelog.  Closes:#769291.

---
 debian/changelog |  1 +
 dgit             | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/debian/changelog b/debian/changelog
index 49b8777..9e8f572 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -97,6 +97,7 @@ dgit (0.23~) unstable; urgency=low
   * For non-Debian distros, debiantag() uses distro name a la DEP-14.
   * dgit: Be more careful about tag updates during fetch: only update
     tags referring to uploads to distro we are trying to fetch from.
+  * dgit: Set up a merge driver for debian/changelog.  Closes:#769291.
 
  --
 
diff --git a/dgit b/dgit
index 802d791..73184fb 100755
--- a/dgit
+++ b/dgit
@@ -1481,6 +1481,33 @@ sub set_local_git_config ($$) {
     runcmd @git, qw(config), $k, $v;
 }
 
+sub setup_mergechangelogs () {
+    my $driver = 'dpkg-mergechangelogs';
+    my $cb = "merge.$driver";
+    my $attrs = '.git/info/attributes';
+    ensuredir '.git/info';
+
+    open NATTRS, ">", "$attrs.new" or die "$attrs.new $!";
+    if (!open ATTRS, "<", $attrs) {
+	$!==ENOENT or die "$attrs: $!";
+    } else {
+	while (<ATTRS>) {
+	    chomp;
+	    next if m{^debian/changelog\s};
+	    print NATTRS $_, "\n" or die $!;
+	}
+	ATTRS->error and die $!;
+	close ATTRS;
+    }
+    print NATTRS "debian/changelog merge=$driver\n" or die $!;
+    close NATTRS;
+
+    set_local_git_config "$cb.name", 'debian/changelog merge driver';
+    set_local_git_config "$cb.driver", 'dpkg-mergechangelogs -m %O %A %B %A';
+
+    rename "$attrs.new", "$attrs" or die "$attrs: $!";
+}
+
 sub clone ($) {
     my ($dstdir) = @_;
     canonicalise_suite();
@@ -1510,6 +1537,7 @@ sub clone ($) {
 	$vcsgiturl =~ s/\s+-b\s+\S+//g;
 	runcmd @git, qw(remote add vcs-git), $vcsgiturl;
     }
+    setup_mergechangelogs();
     runcmd @git, qw(reset --hard), lrref();
     printdone "ready for work in $dstdir";
 }
-- 
cgit v1.2.3