From b6c697655db17a9080849ab40dba7b5a737ffb81 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 25 Aug 2018 17:39:32 +0100
Subject: [PATCH] git-debrebase: Use debchange for new-upstream changelog entry

Closes: #905888.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 git-debrebase               | 55 +++++++++++++++++++++----------------
 tests/tests/gdr-newupstream |  1 +
 2 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/git-debrebase b/git-debrebase
index 4756748a..3d1f2a81 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -2170,30 +2170,39 @@ sub cmd_new_upstream () {
  "[git-debrebase anchor: new upstream $new_upstream_version, merge]",
             ];
 
-	my $clogsignoff = cmdoutput qw(git show),
-	    '--pretty=format:%an <%ae>  %aD',
-	    $new_bw;
-
 	# Now we have to add a changelog stanza so the Debian version
-	# is right.
-	die if unlink "debian";
-	die $! unless $!==ENOENT or $!==ENOTEMPTY;
-	unlink "debian/changelog" or $!==ENOENT or die $!;
-        mkdir "debian" or die $!;
-	open CN, ">", "debian/changelog" or die $!;
-	my $oldclog = git_cat_file ":debian/changelog";
-	$oldclog =~ m/^($package_re) \(\S+\) / or
-	    fail "cannot parse old changelog to get package name";
-	my $p = $1;
-	print CN <<END, $oldclog or die $!;
-$p ($new_version) UNRELEASED; urgency=medium
-
-  * Update to new upstream version $new_upstream_version.
-
- -- $clogsignoff
-
-END
-	close CN or die $!;
+	# is right.  We use debchange to do this.  Invoking debchange
+	# here is a bit fiddly because it has a lot of optional
+	# exciting behaviours, some of which will break stuff, and
+	# some of which won't work in a playtree.
+
+	# Make debchange use git's idea of the user's identity.
+	# That way, if the user never uses debchange et al, configuring
+	# git is enough.
+	my $usetup = sub {
+	    my ($e, $k) = @_;
+	    my $v = cfg $k, 1;
+	    defined $v or return;
+	    $ENV{$e} = $v;
+	};
+	$usetup->('DEBEMAIL',    'user.email');
+	$usetup->('DEBFULLNAME', 'user.name');
+
+sleep 2;
+
+	my @dch = (qw(debchange
+		      --allow-lower-version .*
+		      --no-auto-nmu
+		      --preserve
+		      --vendor=Unknown-Vendor
+		      --changelog debian/changelog
+		      --check-dirname-level 0
+		      --release-heuristic=changelog
+		      -v), $new_version,
+		   "Update to new upstream version $new_upstream_version.");
+
+	runcmd @git, qw(checkout -q debian/changelog);
+	runcmd @dch;
 	runcmd @git, qw(update-index --add --replace), 'debian/changelog';
 
 	# Now we have the final new breakwater branch in the index
diff --git a/tests/tests/gdr-newupstream b/tests/tests/gdr-newupstream
index b45a0bfe..300d4345 100755
--- a/tests/tests/gdr-newupstream
+++ b/tests/tests/gdr-newupstream
@@ -31,6 +31,7 @@ git branch before-new-upstream
 clog-check-1 () {
 	before=$1
 	date=$(git log --format=%aD -n1 debian/changelog)
+	date=$(date -R -d "$date")
 	git show $before:debian/changelog >../clog.before
 	m="  * Update to new upstream version ${v%-*}."
 	e="dgit test git user <dgit-test@debian.example.net>  $date"
-- 
2.30.2