git-debrebase: new-upstream: fix ff check handling of multi-piece upstreams

Multi-piece combine commits may have n or n+1 parents, depending on
whether the previous new-upstream invocation was snag-free.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/debian/changelog b/debian/changelog
index a70ec3849edd9985f6ea6b5a3ef4a06b0f868def..fc7aebb8f976e44844a17668055251ffbcbb28eb 100644 (file)
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,8 @@
 dgit (5.1~) unstable; urgency=medium
 
   * git-debrebase manpages: Fix typos and etc.
+  * git-debrebase: new-upstream: fix (this time for sure) ff check
+    handling of multi-piece upstreams.
 
  --
 

diff --git a/git-debrebase b/git-debrebase
index 9e8d7075d42e32bb24a270ecaf9db217162c4ad0..3458b12f5d86d93c2de804989afbed423cc43e92 100755 (executable)
--- a/git-debrebase
+++ b/git-debrebase
@@ -1216,11 +1216,13 @@ sub cmd_new_upstream () {
           ) {
            my @oldpieces = (split / /, $1);
            my $old_n_parents = scalar @{ $old_upstream->{Parents} };
-           if (@oldpieces != $old_n_parents) {
+           if ($old_n_parents != @oldpieces &&
+               $old_n_parents != @oldpieces + 1) {
                snag 'upstream-confusing', sprintf
                    "previous upstream combine %s".
-                   " mentions %d pieces (each implying one orig commit)".
-                   " but has %d parents",
+                   " mentions %d pieces (each implying one parent)".
+                   " but has %d parents".
+                   " (one per piece plus maybe a previous combine)",
                    $old_upstream->{CommitId},
                    (scalar @oldpieces),
                    $old_n_parents;
@@ -1233,7 +1235,8 @@ sub cmd_new_upstream () {
                $oldpieces[0] = '';
                foreach my $i (0..$#oldpieces) {
                    my $n = $oldpieces[$i];
-                   $piece->($n, Old => $old_upstream->{CommitId}.'^'.($i+1));
+                   my $hat = 1 + $i + ($old_n_parents - @oldpieces);
+                   $piece->($n, Old => $old_upstream->{CommitId}.'^'.$hat);
                }
            }
        } else {