From 302a82c5e9e200fe93befefbdeb2b9ccfac00239 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 6 Jan 2017 18:29:00 +0000
Subject: Protocol change: Add distro info to Dgit field

Downstream clients may need this to get the relevant git commits.
Worse, with the new rewrite functionality, they may get the _wrong_
commits because they may not be rewritten.

For now we implement the publication side.  The reader side is
theoretically straightforward, but probably not so simple in reality,
and certainly fiddly to test.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 debian/changelog | 7 ++++++-
 dgit             | 7 +++++--
 dgit.7           | 7 +++++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/debian/changelog b/debian/changelog
index b72ac69..562e415 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,4 +1,9 @@
-dgit (2.17~) unstable; urgency=medium
+dgit (3.0~) unstable; urgency=medium
+
+  Protocol change:
+  * Dgit: field now records the nominal distro name, and a hint
+    for a tag and url where the git objects (including any rewrite
+    map) can be fetched..
 
   Bugfixes:
   * dgit config handling: Honour command-line and context-provided
diff --git a/dgit b/dgit
index 0ae84b2..54c38c2 100755
--- a/dgit
+++ b/dgit
@@ -3723,7 +3723,11 @@ sub push_mktags ($$ $$ $) {
 
     die unless $tagwants->[0]{View} eq 'dgit';
 
-    $dsc->{$ourdscfield[0]} = $tagwants->[0]{Objid};
+    my $declaredistro = access_nomdistro();
+    my $reader_giturl = do { local $access_forpush=0; access_giturl(); };
+    $dsc->{$ourdscfield[0]} = join " ",
+	$tagwants->[0]{Objid}, $declaredistro, $tagwants->[0]{Tag},
+	$reader_giturl;
     $dsc->save("$dscfn.tmp") or die $!;
 
     my $changes = parsecontrol($changesfile,$changesfilewhat);
@@ -3740,7 +3744,6 @@ sub push_mktags ($$ $$ $) {
     # to control the "tagger" (b) we can do remote signing
     my $authline = clogp_authline $clogp;
     my $delibs = join(" ", "",@deliberatelies);
-    my $declaredistro = access_nomdistro();
 
     my $mktag = sub {
 	my ($tw) = @_;
diff --git a/dgit.7 b/dgit.7
index f7e50e4..584632c 100644
--- a/dgit.7
+++ b/dgit.7
@@ -56,8 +56,11 @@ server to authenticate pushes.
 Uploads made by dgit contain an additional field
 .B Dgit
 in the source package .dsc.  (This is added by dgit push.)
-This specifies a commit (an ancestor of the dgit/suite
-branch) whose tree is identical to the unpacked source upload.
+This specifies: a commit (an ancestor of the dgit/suite
+branch) whose tree is identical to the unpacked source upload;
+and the distro and suite to which the upload was made
+(and a url,
+in case the client seeing this .dsc does not know of that distro).
 
 Uploads not made by dgit are represented in git by commits which are
 synthesised by dgit.  The tree of each such commit corresponds to the
-- 
cgit v1.2.3